After the collision, the players will stick together and move with the same velocity. Their speed can be determined by using conservation of momentum. This law states that magnitude and direction of momentum is the same before and after a collision. This is represented by the equation m1v1+m2v2 = m1v1+m2v2, where the velocities on either side may be different.
Another use for momentum can be seen as two players throw basketballs in opposite directions, causing them to collide head-on.
After the balls collide, they will bounce backwards, completely changing their direction. If the two balls together have the same kinetic energy after the collision than they had before, the collision is considered elastic. This means that their kinetic energy was conserved. If it was not conserved, the collision was inelastic. This can be determined by comparing kinetic energy before and after collision by using the fact that kinetic energy is equal to mass times velocity squared. (Ek=mv2)
Momentum can also be applied to the situation where a tennis ball and baseball are thrown against a garage door. The tennis ball will bounce back off the wall with the same velocity in which it was thrown, but the baseball will not bounce and will stop when it collides. Assuming the balls have the same mass and initial velocity, which is more damaging to the garage door? Consider the change in velocity for each ball after they collide with the door.
The baseball goes from its initial velocity to rest, while the tennis ball goes to the same speed in the opposite direction. This means that there has been a larger change in the tennis ball's momentum and that there has been a larger impulse applied to it. Impulse is the force times time, so the force that the wall applies to the tennis ball must be greater. Newton's 3rd law says that a force of equal magnitude must also be applied on the door, so the tennis ball would damage the door more.
Momentum is conserved all around us, especially in things that we do everyday. Physics always has an explanation for these natural phenomena. -David Wolfers AP Physics 1 Marking Period 3