Using mass and speed data from Figure and assuming that the football player catches the ball with his feet off the ground with both of them moving horizontally, calculate: a the final velocity if the ball and player are going in the same direction and b the loss of kinetic energy in this case. Might the loss of kinetic energy be related to how much it hurts to catch the pass? Calculate its recoil velocity. This energy is less than the energy released by the gun powder—significant heat transfer occurs.
Two piloted satellites approaching one another, at a relative speed of 0. The first has a mass of , and the second a mass of. Explain why the change in velocity is different in the two frames, whereas the change in kinetic energy is the same in both. Because there are no external forces, the velocity of the center of mass of the two-satellite system is unchanged by the collision. The two velocities calculated above are the velocity of the center of mass in each of the two different individual reference frames.
The loss in KE is the same in both reference frames because the KE lost to internal forces heat, friction, etc.
A 30,kg freight car is coasting at 0. Space probes may be separated from their launchers by exploding bolts. They bolt away from one another. Suppose a kg satellite uses this method to separate from the kg remains of its launcher, and that J of kinetic energy is supplied to the two parts.
What are their subsequent velocities using the frame of reference in which they were at rest before separation? The pain is related to the amount of kinetic energy, which is significantly less in this latter situation.
Discuss its relationship to this problem. One of the waste products of a nuclear reactor is plutonium This nucleus is radioactive and decays by splitting into a helium-4 nucleus and a uranium nucleus , the latter of which is also radioactive and will itself decay some time later.
The energy emitted in the plutonium decay is and is entirely converted to kinetic energy of the helium and uranium nuclei. The mass of the helium nucleus is , while that of the uranium is note that the ratio of the masses is 4 to Note that the data given here are accurate to three digits only. Suppose a fairly large asteroid that has a mass of about a kilometer across strikes the Moon at a speed of Such an event may have been observed by medieval English monks who reported observing a red glow and subsequent haze about the Moon.
Significant amounts of water were detected. Answer part a and b for this real-life experiment. How does the plume produced alter these results? The plume will not affect the momentum result because the plume is still part of the Moon system. The plume may affect the kinetic energy result because a significant part of the initial kinetic energy may be transferred to the kinetic energy of the plume particles.
Two football players collide head-on in midair while trying to catch a thrown football. The first player is What is their velocity just after impact if they cling together? What is the speed of a garbage truck that is and is initially moving at During a circus act, an elderly performer thrills the crowd by catching a cannon ball shot at him. The cannon ball has a mass of If the performer is on nearly frictionless roller skates, what is his recoil velocity?
If the clown recoils with a velocity of 0. The muscles convert the chemical potential energy of ATP into kinetic energy. Skip to content Linear Momentum and Collisions. Learning Objectives Define inelastic collision. Explain perfectly inelastic collision. Apply an understanding of collisions to sports.
In a perfectly elastic collision, the energy conversions show no net energy loss. As a real-life example, collisions of atoms is a nearly perfectly elastic collision. For example, Rutherford backscattering is an application of elastic collision of atoms. Furthermore, molecules in gases or liquids rarely show perfectly elastic collisions. In addition to these, we can approximate perfectly elastic collisions by the interactions of objects such as billiard balls. A perfectly inelastic collision is the physical process of striking one object against another without conserving the kinetic energy of two objects.
This is the opposite of a perfectly elastic collision. The kinetic energy is not conserved in a perfectly inelastic collision because of the internal friction. However, inelastic collisions tend to obey conservation of momentum although these collisions do not conserve kinetic energy. In the field of nuclear physics, we can identify inelastic collisions in incoming particles that cause the nucleus to become excited or to break up.
Explanation: Assumption: Inelastic collision imply partially inelastic collision. Let us define a quantity, Coefficient of restitution e The coefficient of restitution COR is a measure of the kinetic energy remaining in the objects; involved in collision, after rebound from one another as compared to kinetic energy lost as heat, or as work done in deforming the colliding objects. Related questions In a collision between two objects of identical mass, could the acceleration values be different? Is momentum conserved in an elastic collision but not in an inelastic collision?
What are some examples of a coefficient of restitution? Can the coefficient of restitution be negative? Does the coefficient of restitution change? How do you calculate inelastic collisions?
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