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# Change in kinetic energy formula inelastic collision

The amount of kinetic energy that is lost during an inelastic collision can be found by combining the principle of conservation of the energy and the principle of conservation of the momentum. Suppose an object with mass m ₁ moves with velocity v ₁. This object now collides with another object of mass m ₂ which wasn't moving Inelastic Collisions Perfectly elastic collisions are those in which no kinetic energy is lost in the collision. Macroscopic collisions are generally inelastic and do not conserve kinetic energy, though of course the total energy is conserved as required by the general principle of conservation of energy.The extreme inelastic collision is one in which the colliding objects stick together after.

While the total energy of a system is always conserved, the kinetic energy carried by the moving objects is not always conserved. In an inelastic collision, energy is lost to the environment, transferred into other forms such as heat. 5 \sqrt {2} 5 2 5. An inelastic collision is one in which the internal kinetic energy changes (it is not conserved). Figure 8.8 shows an example of an inelastic collision. Two objects that have equal masses head toward one another at equal speeds and then stick together. Their total internal kinetic energy is initiall In an inelastic collision kinetic energy is not conserved, but momentum is conserved. Details of the calculation: m 1 u 1 = (m 1 + m 2)v. E f = ½ (m 1 + m 2)v 2, E i = ½ m 1 u 12

An inelastic collision is one in which the internal kinetic energy changes (it is not conserved). This lack of conservation means that the forces between colliding objects may remove or add internal kinetic energy. Work done by internal forces may change the forms of energy within a system. For inelastic collisions, such as when colliding. Getting this into the fractional change equation is straight-forward from here. Now, the negative sign here indicates that energy is lost in the collision. This should make sense since (a) inelastic collisions expect the non-conservation of KE and (b) you can't gain energy here without some source. Thus, the only option is the final state must. Elastic And Inelastic Collisions Equations. Elastic Collision Formula; An elastic collision occurs when both the Kinetic energy (KE) and momentum (p) are conserved. If we explain in other words, it will be; KE = ½ mv2. We can write; 1/2 m 1 (v 1i) 2 + 1/2 m 2 (v 2i) 2 =1/2m 1 (v 1f) 2 + 1/2 m 2 (v 2f) The car's velocity just before the collision was < 35, 0, 0 > m/s, and the truck's velocity just before the collision was < -18, 0, 27 > m/s. Homework Equations P f =P i +F*time E f =E i +Q+W The Attempt at a Solution I attempted to use the change in kinetic energy of the system to solve of the change in internal energy. E f =.5*m*v

In physics, an inelastic collision occurs, when the maximum amount of kinetic energy of a colliding objects/system is lost. The colliding particles stick together in a perfectly inelastic collision. In such cases, kinetic energy lost is used in bonding the two bodies together This video demonstrates calculations using conservation of momentum and kinetic energy for an inelastic collision. Visit https://sites.google.com/site/dcaul..

An inelastic collision is one in which the internal kinetic energy changes (it is not conserved). Figure 7.6. 1 shows an example of an inelastic collision. Two objects that have equal masses head toward one another at equal speeds and then stick together. Their total internal kinetic energy is initiall The Equation for a perfectly inelastic collision: m 1 v 1i + m2 v 2i = (m 1 + m 2) v f Proving Kinetic Energy Loss You can prove that when two objects stick together, there will be a loss of kinetic energy Inelastic Collision Their total internal kinetic energy is initially 12mv2+12mv2=mv2 1 2 m v 2 + 1 2 m v 2 = m v 2. The two objects come to rest after sticking together, conserving momentum. But the internal kinetic energy is zero after the collision. What is the formula for perfectly inelastic collision Inelastic Collision Formula Questions: 1) A man shoots a paintball at an old can on a fencepost. The paintball pellet has a mass of 0.200 g, and the can has a mass of 15.0 g.The paintball hits the can at a velocity of 90.0 m/s.If the full mass of the paintball sticks to the can and knocks it off the post, what is the final velocity of the combined paintball and can An inelastic collision is one in which the internal kinetic energy changes (it is not conserved). A collision in which the objects stick together is sometimes called perfectly inelastic because it reduces internal kinetic energy more than does any other type of inelastic collision

A classic example of an inelastic collision is a motor car accident. The cars change shape and there is a noticeable change in the kinetic energy of the cars before and after the collision. This energy was used to bend the metal and deform the cars. Another example of an inelastic collision is shown in the figure below initial kinetic energy of a perfectly inelastic collision. Remember for an inelastic collision, kinetic energy is NOT conserved but momentum IS. Using conservation of momentum (p~i = p~f)andthefactthatCart#2isinitially at rest gives: m1~v1i +m2~v2i = m1~v1i =(m1 +m2)~vf (5.9) Using Eqs. 5.7, 5.8,and5.9, we arrive at an equation for KEf in terms. Inelastic Collision Formula Concept of inelastic collision: An inelastic collision is such a type of collision which takes place between two objects. Also, there will be some loss of energy. In these cases of inelastic collision, momentum is always conserved but the kinetic energy is not conserved. Most of the collisions are inelastic in nature Loss of kinetic energy during perfectly inelastic collision, in this type of collision, the objects involved in the collisions do not stick, but some kinetic energy is still lost. Friction, sound and heat are some ways the kinetic energy can be lost through partial inelastic collisions. ⓘ Loss of Kinetic Energy during a perfectly inelastic collision [E L The change in kinetic energy is, These formulas show that the change in kinetic energy is related to the distance over which a force acts, whereas the change in momentum is related to the time over which a force acts. An example is the collision between a tennis racket and a tennis ball

### Kinetic Energy In Inelastic Collision - Cheg

Another perfectly inelastic collision The reduction of total kinetic energy is equal to the total kinetic energy before the collision in a center of momentum frame with respect to the system of two particles, because in such a frame the kinetic energy after the collision is zero Infer: Why do you think some of the kinetic energy is lost during an inelastic collision? It is possible that the kinetic energy was converted to other types of energy (such as thermal energy) instead of being transferred to the other puck. 7. Think about it: Suppose a meteorite collided head-on with Mars and becomes buried under Mars's surface ### Inelastic Collisions - HyperPhysics Concept

• Conservation of kinetic energy example Question. A red snooker ball and a blue snooker ball (each with a mass of 160 g) collide. The red ball is travelling from left to right at 0.28 ms-1.The blue.
• we need to derive an equation that relates the nal kinetic energy to the initial kinetic energy of a perfectly inelastic collision. Remember for an inelastic collision, kinetic energy is NOT conserved but momentum IS. Using conservation of momentum (p~i= p~f) and the fact that Cart #2 is initially at rest gives: m1~v1i+ m2~v2i= m1~v1i= (m1 + m2.
• An inelastic collision is one in which the internal kinetic energy changes (it is not conserved). Figure 7.6. 1 shows an example of an inelastic collision. Two objects that have equal masses head toward one another at equal speeds and then stick together. Their total internal kinetic energy is initially. (7.6.1) 1 2 m v 2 + 1 2 m v 2 = m v 2
• fractional change in kinetic energy of the car is Mechanical Energy Changes in Perfectly Inelastic Collisions Carl E. Mungan, U.S. Naval Academy, Annapolis, MD S uppose a block of mass m 1 traveling at speed u 1 makes a one-dimensional perfectly inelastic collision with another block of mass m 2. What else does one need t
• Collisions are considered inelastic when kinetic energy is not conserved, but this could be from either a loss or gain or kinetic energy. For example, in an explosion-type collision, the kinetic energy increases. It is common for people to try to conserve energy in a collision. We can only do this if we are told the collision is perfectly elastic
• • Notice in the table below how the change in total kinetic energy goes hand in hand with a change in the state. • To explore this connection further let us introduce a new quantity called internal energy: • In an inelastic collision one form of energy is converted to another form of energy (kinetic to internal)
• The Final Velocity of an Inelastic collision is a collision in which kinetic energy is not conserved due to the action of internal friction. The final velocity of the first object after impact is found using the following formula: va = CRmb(ub − ua)+ maua +mbub ma +mb v a = C R m b ( u b - u a) + m a u a + m b u b m a + m b, where: ua u a.

Inelastic collisions. In this section, we give a few examples of modelling inelastic collisions. Inelastic collisions are usually easier to handle mathematically, because one only needs to consider conservation of momentum and does not use conservation of energy (which usually involves equations that are quadratic in the speeds because of the kinetic energy term) conserved in an inelastic collision. Likewise, mass does not have to be conserved since it can be converted into energy. However, the total energy (kinetic, rest mass, and all other potential energy forms) is always conserved in Special Relativity. Momentum and energy are conserved for both elastic and inelastic collisions when the relativisti Total kinetic energy is the same before and after an elastic collision Note that the kinetic energy is not calculated for each direction separately, but depends on the magnitude of the total velocity of each object. Viewgraphs Viewgraph 1 Viewgraph 2 Viewgraph 3 Viewgraph 4 Viewgraph 5 Viewgraph 6 Viewgraph 7.

### Determining Kinetic Energy Lost in Inelastic Collisions

• Completely inelastic collisions involve objects which stick together afterwards. Kinetic energy is not conserved, but the result is easy to calculate via conservation of momentum. Partially inelastic collisions involve objects which separate after they collide, but which are deformed in some way by the interaction
• e both the initial and final kinetic energy. Section 3 Elastic and Inelastic Chapter 6 Collisions 22 1, 2, 1 1, 2 2,
• Formulas Used: In an elastic collision both kinetic energy and momentum are conserved. In the following equations, 1 and 2 indicate the two different objects colliding, unprimed variables indicates those before collision and primed variables indicate those after the collision, p is momentum, KE is kinetic energy, M is mass, and V is velocity
• Even though the velocities change in the inelastic collision, the momentum still adds up to 1, but the energy square law cannot follow. Mathematics permits the system to have the same momentum but a different kinetic energy after the collision. The blue line is a line of constant momentum of 1 kg m/s Inelastic Collisions Object: To see if momentum and energy are conserved for an inelastic collision. Apparatus: Ballistic pendulum, two-meter stick, tray with carbon paper, balance, and ruler. Foreword The momentum p of a body is defined as the product of its mass m and velocity v , or (1) p = mv The equation to calculate the change in total kinetic energy is: Substitute all the values in the above equation. this is called an inelastic collision. In this lesson, learn how to. Elastic and inelastic collisions. As in all collisions, momentum is conserved in this example. But calculations comparing kinetic energy before and after the collision show kinetic energy is not. An inelastic collision is one in which the internal kinetic energy changes (it is not conserved). This lack of conservation means that the forces between colliding objects may remove or add internal kinetic energy. Work done by internal forces may change the forms of energy within a system

### 8.5 Inelastic Collisions in One Dimension - College ..

The collision is the mutual interaction between two particle s for a short interval of time so that their momentum and kinetic energy may change. A collision is an isolated event in which two or more colliding bodies exert relatively strong force s on each other for a relatively short time. Actual physical contact is not necessary for a collision In an elastic collision, the momentum and total kinetic energy before and after the collision is the same. In an inelastic collision, the energy changes into other energies such as sound energy or thermal energy. In an inelastic collision, the energy is not conserved

### Inelastic collisions - University of Tennesse

The total system kinetic energy before the collision equals the total system kinetic energy after the collision. If total kinetic energy is not conserved, then the collision is referred to as an inelastic collision. The animation below portrays the elastic collision between a 3000-kg truck and a 1000-kg car Based upon your observations, define inelastic collisions. (1) A 50% inelastic collision occurs between a 0.7 kg ball moving to the left with a velocity of 1.8 m/s and a 1.6 kg ball moving to the right at 0.5 m/s. After the collision, the 1.6 kg ball moves to the left with a velocity of 0.55 m/s. The formula for kinetic energy of an object is. Relativistic collisions do not obey the classical law of conservation of momentum. According to classical mechanics, the kinetic energy of A before the collision, as calculated by an observer in F, is mv 2 /2. The kinetic energy of B before the collision is zero. After the collision, the kinetic energy of A and B combined is 2mu 2 /2 In an inelastic collision, the colliding objects stick together and the total kinetic energy noticeably decreases during the collision. Although kinetic energy of the system decreases during an inelastic collision, there is no loss of momentum by the system. Solve problems involving inelastic collisions using conservation of momentum In an inelastic collision kinetic energy is lost (generally through energy used to change an objects shape), but the two objects rebound off each other with the remaining kinetic energy. In a perfectly inelastic collision, i.e., a zero coefficient of restitution, the colliding particles stick together Equation (6), however, is only true in an elastic collision. In the real-world there is a percentage of kinetic energy lost during the collisions of ball 2 with the ground and ball 1 with ball 2. The energy ball 1 loses can be accounted for by multiplying the pre-collision kinetic energy by a factor of. (9 (4), the fractional change in kinetic energy of the car is Mechanical Energy Changes in Perfectly Inelastic CollisionsCarl E. Mungan, U.S. Naval Academy, Annapolis, MD S uppose a block of mass m 1 traveling at speed u 1 makes a one-dimensional perfectly inelastic collision with another block of mass m 2 When there is a collision between multiple objects and the final kinetic energy is different from the initial kinetic energy, it is said to be an inelastic collision.In these situations, the original kinetic energy is sometimes lost in the form of heat or sound, both of which are the results of the vibration of atoms at the point of collision

### Inelastic Collisions in One Dimension Physic

1. Collisions. A collision is when two objects strike each other over a short space of time. The momentum of each object can change, but the total momentum does not. We say the momentum is conserved (the total stays the same).. Momentum is Conserved. Conserved: the total stays the same (within a closed system).. Closed System: nothing transfers in or out, and no external force acts on it
2. Infer: Why do you think some of the kinetic energy is lost during an inelastic collision? It is possible that the kinetic energy was converted to other types of energy (such as thermal energy) instead of being transferred to the other puck. 7. Think about it: Suppose a meteorite collided head-on with Mars and becomes buried under Mars's surface
3. An inelastic collision, in contrast to an elastic collision, is a collision in which kinetic energy is not conserved due to the action of internal friction.. In collisions of macroscopic bodies, some kinetic energy is turned into vibrational energy of the atoms, causing a heating effect, and the bodies are deformed.. The molecules of a gas or liquid rarely experience perfectly elastic.
4. As mentioned earlier, the coefficient of restitution is a measure of how much kinetic energy remains after the collision of two bodies. Its value ranges from 0 to 1. If it's on the higher side (i.e., close to 1), it suggests that very little kinetic energy is lost during the collision; on the other hand, if the value is low, it indicates that.
5. Inelastic scattering occurs above a threshold energy. This threshold energy is higher than the energy the first excited state of target nucleus (due to the laws of conservation) and it is given by following formula: E t = ((A+1)/A)* ε 1. where E t is known as the inelastic threshold energy and ε 1 is the energy of the first excited state
6. During the inelastic collisions, some kinetic energy turns into the shock wave (elastic deformation) and heat. It means that the equation (7) changes, that is, the kinetic energy of Block #1 before the impact of the blocks should be more than the total kinetic energy of the blocks after the impact

### How do I show the fractional change in Kinetic Energy in a

But the kinetic energy is defined as : KE = \frac{1}{2}mv^2KE= 2 1 mv 2 , so with half the mass, but twice the squared-velocity, crate A will have the same kinetic energy as crate B. Which of the following quantities is conserved in all three types of collisions : elastic, inelastic, and perfectly inelastic SECTION 6.3 Elastic and Inelastic Collisions Collisions The total momentum remains constant in all collisions. But in many collisions, the total kinetic energy is not conserved. If the shape of the object or objects changes because of the collision, some energy went into changing the shape. This section will look at two types of collisions: perfectly inelastic collisions and elastic collisions In an elastic collision both energy and momentum are conserved. An Inelastic collision is one in which the objects stick together. Good examples of inelastic collisions are a ball of putty hitting and sticking to another ball or two railroad cars colliding and coupling together. In an inelastic collision momentum is conserved, but energy is not

### Elastic and Inelastic Collisions - Equations, Types and

1. Its dimensional formula is [ML 2 T-3]. What is Collision? A collision is an event where a strong force acts for a very short span of time between two or more bodies. A collision is an isolated event. The energy and momentum of the interacting particles undergo a change as a result of the collision
2. The inelastic collision also observes momentum conservation but not kinetic energy conservation. It is also interesting to note that during the heart of the elastic collision, even kinetic energy is not conserved since some energy is temporarily stored in the spring as potential energy. Solving elastic and inelastic collision problems
3. Inelastic Collisions which Do NOT Conserve Kinetic Energy! Some initial kinetic energy is lost to thermal or potential energy. Kinetic energy may also be gained in explosions (there is addition of chemical or nuclear energy). A Completely Inelastic Collision is one in which the objects stick together afterward, so there is only one final velocity

### Change in internal energy of an inelastic collision

Inelastic Collisions . A collision is considered to be an inelastic collision if the linear momentum of the system is retained, but the kinetic energy is not maintained. Example Questions. Here are a few important example questions to make you thorough in work, energy and power class 11. Comets are passing around the sun in extremely elliptical. Problem 34 Medium Difficulty. (II) (a) Derive a formula for the fraction of kinetic energy lost, Δ K E / K E, in terms of m and M for the ballistic pendulum collision of Example 7-9. (b) Evaluate for m = 18.0 g and M = 380 g

### 8.5 Inelastic Collisions in One Dimension - College Physic

1. Q.10. A particle of mass m moving in the x direction with speed 2v is hit by another particle of mass 2m moving in the y direction with speed v. If the collision is perfectly inelastic, the percentage loss in the energy during the collision is close to. (a) 56%. (b) 62%. (c) 44%. (d) 50%. Answer
2. Kinetic Energy is not conserved in the majority of collisions; which are called inelastic collisions. Potential Energy is the height to which an object with kinetic energy will rise. So potential and kinetic energy are not conserved in inelastic c..
3. Derive a formula that predicts the fractional loss in the total kinetic ener gy of both gliders after the collision compared to before the collision in terms of the two masses only. Data: Record the mass of each glider, including all attached cylinders. Find the effective length for each photogate with the flag that goes through it
4. In an inelastic collision the total kinetic energy after the collision is not equal to the total kinetic energy before the collision. If there are no net forces at work (i.e., collision takes place on a frictionless surface and there is negligible air resistance ), there must be conservation of total momentum for the two masses
5. In a totally inelastic collision, all of kinetic energy of relative motion is converted into heat have to change, so the sign in eq. (22) should be ' '. Multiplying both sides of this equation (10).) Clearly, this is a much more complicated equation system than just two linear eqs. (22) and (23) for the head-on elastic collisions

An elastic collision is one in which the objects bounce off of each other without change of their total mechanical kinetic energy. An inelastic collision is one in which some of the mechanical kinetic energy of the colliding objects is converted into other forms of energy. For example, friction forces may result in the creatio change in the kinetic energy of the particle while Impulse-Momentum theorem is a vector equation dealing with the change of momentum of the particles. Consider an inelastic collision in which the kinetic energy is not conserved, however momentum is conserved. Physics (HRK) Chapter 10: Collisions. An inelastic collision is in contrast to an elastic collision is a collision in which the energy which is the kinetic energy is not conserved due to the action of internal friction.In collisions of bodies which are macroscopic bodies and some of the energy which is the kinetic energy is turned into vibrational energy of the atoms which cause a heating effect and the bodies are deformed Collisions: In physics, we separate collisions into several categories: Completely inelastic: the objects stick together after the collision. Kinetic energy is not conserved. Partially inelastic: the objects separate after they collide, but are deformed in some way. Kinetic energy is not conserved

### What is Inelastic Collision? - Definition, Formula, Example

In inelastic one dimensional collision, the colliding masses stick together and move in the same direction at same speeds. The momentum is conserved and Kinetic energy is changed to different forms of energies. For inelastic collisions the equation for conservation of momentum is : m1u1 + m2u2 = (m1 + m2) v Justification: This is an example of an inelastic collision. In these types of collisions kinetic energy is not conserved (it is converted into some other form of energy, such as heat energy or energy of deformation). However, no matter if it is an elastic collision (kinetic energy is conserved) or an inelastic collision, momentum would still b Activity 6 Collisions and energy. Objective: To explore the conservation of kinetic energy in collisions. Activity 6.1 Classification of collisions; convertible energy In the previous activity you saw three collisions between carts with equal masses, all with different outcomes, yet in all of them the total momentum was conserved. In general, the total momentum of a system will be conserved if. A10) Was the increase in kinetic energy of Car2 equal in size to the decrease in KE of Car1? Why or why not? A11) Was kinetic energy conserved in the collision? ____ Explain. A12) Was energy conserved in the collision? _____ Explain. B. Experiment: Complete Inelastic Collision. Load Car1 with 800grams added mass An inelastic collision does not conserve kinetic energy. Momentum is conserved regardless of whether or not kinetic energy is conserved. Analysis of kinetic energy changes and conservation of momentum together allow the final velocities to be calculated in terms of initial velocities and masses in one-dimensional, two-body collisions  Definition: An inelastic collision is opposite to an elastic collision. It is a collision in which kinetic energy is not maintained An elastic collision is defined as one in which there is no loss of kinetic energy in the collision, while an inelastic collision is one in which part of the kinetic energy is changed to some other form of energy in the collision. In the following two videos, we learn about elastic and inelastic collisions and compare the momentum and kinetic.

Inelastic collisions also occur during squash/racquetball/handball games: in each case, the ball becomes warm to the touch after a long game, because some fraction of the ball's kinetic energy of collision with the walls of the court has been converted into heat energy. Equation remains valid for inelastic collisions--however, Eq. is invalid. Conservation of kinetic energy: To obtain expressions for the velocities after the collision, rewrite the above as: Dividing these relationships gives: which may be substituted into equation (2) above to obtain: Note that these equations apply only to the case where the target is at rest A collision in which the total momentum and total kinetic energy is conserved. The total momentum is always constant throughout the collision. In addition, if the collision is perfectly elastic, the value of the total kinetic energy after the collision is equal to the value before the collision. m₁v₁i + m₂v₂i = m₁v₁f + m₂v₂f. A collision between two objects must either be elastic or inelastic. In an elastic collision, both the momentum and the kinetic energy of the system are conserved. In the case of the ballistic pendulum, the collision is inelastic because the bullet is embedded in the block These collisions can cause a change in kinetic energy via: a loss in kinetic energy, an increase in kinetic energy, or no effective kinetic energy loss at all. These types of collisions are known as inelastic collision, perfectly inelastic collision, elastic collision, and super elastic collision. You can read about each of them below

Calculator. Formula. Inelastic collisions has some loss of kinetic energy in the collision. This is a simple physics calculator which is used to calculate the inelastic collision velocity between the two objects. Code to add this calci to your website. Just copy and paste the below code to your webpage where you want to display this calculator As a continuation of the theme of potential and kinetic energy, this lesson introduces the concepts of momentum, elastic and inelastic collisions. Many sports and games, such as baseball and ping-pong, illustrate the ideas of momentum and collisions. Students can use the associated activities to explore these concepts by bouncing assorted balls on different surfaces and calculating the. In collision, particle is change the one form of kinetic energy to another form is called as inelastic collision. Not conserved kinetic energy is collide the particles and in atoms the vibrational energy is converted from kinetic energy. Kinetic energy does not conserved by inelastic collision but it conserve the momentum A perfectly inelastic collision (or completely inelastic collision) is a specific case of inelastic collision in which the two colliding body stick together and move as one mass after the collision. The change in momentum for this is given by ΔP = P f − P i = (m 1 +m 2)v f −(m 1 v 1i +m 2 v 2i) = 0 (Equation 6) and the change in kinetic. Inelastic collision of two equal masses with one initially at rest. 1. In Part 1/6 determine the time when the right edge if the incident cart crosses the 20 cm mark on the scale. Determine the time when the two carts just contact by noting the change in the previously stationary cart, and at that time the positions of the right edge of the. Figure 3: An inelastic collision between two particles, releasing X J of sound and heat. Figure 3 shows an inelastic collision between two particles, both of mass m, m, in which delta, K, equals, X, J, Δ K = X J of sound and heat are produced. The particle motion involved in the sound and heat has net zero momentum total kinetic energy after collision = 0.4 + 2.45 = 2.85 J (2.9 2sf) You can see from the calculations that kinetic energy is not conserved in this collision of two objects. This is an inelastic collision. The atoms of the object are compressed and kinetic energy is converted into potential energy, thermal energy and sound The collision between two steel or glass balls is nearly elastic. In elastic collisions, the forces involved during interaction are of conservative in nature. Inelastic collision: Collisions in which momentum of the system is conserved but not the kinetic energy are called inelastic collisions. Most collision in everyday life is inelastic There are two main types of collision: elastic and inelastic. In the case of elastic collision, both the kinetic energy K and momentum p are conserved. This means that the sum of the momenta before the collision will be equal to the sum of momenta after the collision. The same applies for the kinetic energy The initial kinetic energy of the system is. The final kinetic energy of the system is. Note: not all the kinetic energy can be lost, even in a completely inelastic collision, since the motion of the center of mass must still be present. Only if our reference frame is chosen such that the center-of-mass velocity is zero, will the final kinetic. In elastic collisions kinetic energy was always conserved. Therefor elastic collisions can be defined as collisions in which kinetic energy is conserved. In inelastic collisions kinetic energy was not conserved because the value of the ratio of initial and final kinetic energy was not close to one If the collision is elastic, write down the kinetic energy conservation equation. If the collision is inelastic, additional information may be required. If totally inelastic, the final velocities of both particles are equal. Use other information given. E.g. Direction of one of the final velocities. Next: What is centre of mass