Chapter 7- Momentum- Physics- Davis
Internal forces cannot change the total kinetic energy of a system.
False
The impulse delivered to an object is equal to the change in the object's velocity.
False
Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system?
The final momentum is zero kg∙m/s but the final kinetic energy is positive.
Identical forces act for the same length of time on two different masses. The change in momentum of the smaller mass is
equal to the change in momentum of the larger mass
Identical forces act for the same length of time on two different objects. The magnitude of the change in momentum of the lighter object is
exactly equal to the magnitude of the change in momentum of the larger mass
In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is <<<< >>>>
perfectly elastic
A rubber ball and a lump of putty have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The putty sticks to the wall. Which objects experiences the greater momentum change?
the ball
A tiger is running in a straight line. If we double both the mass and speed of the tiger, the magnitude of its momentum will increase by what factor?
4
You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You have two choices about what to do with the ball: either catch the ball or deflect it back toward your friend with the same speed as it was originally thrown. Which choice should you make in order to maximize your speed on the skateboard?
Deflect the ball back
A system that has zero momentum must also have zero kinetic energy.
False
When objects stick together after colliding, the collision is completely elastic.
False
A freight car moves along a frictionless level railroad track at constant speed. The freight car is open on top. A large load of coal is suddenly dumped into the car. What happens to the speed of the freight car?
It decreases
A ping-pong ball moving east at a speed of 4 m/s, collides with a stationary bowling ball. The Ping-Pong ball bounces back to the west, and the bowling ball moves very slowly to the east. Which object experiences the greater magnitude impulse during the collision?
Neither; both experienced the same magnitude impulse.
An artillery shell explodes in midair and breaks up into many fragments. Which of the following statements are true regarding conditions immediately before and immediately after the explosion: I. The total momentum of the fragments is equal to the original momentum of the shell. II. The total kinetic energy of the fragments is equal to the original kinetic energy of the shell.
Statement I only
A tennis ball undergoes an elastic collision when it hits the ground and bounces up. It is given that the speed of the ball just before it hits the ground is -v0 and immediately after rebounding it is +v0. Which of the statements below is true?
The momentum of the ball changes and the momentum of Earth also changes by the same amount
A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the momentum during the collision are correct? (There could be more than one correct choice.)
The momentum of the car-truck system is conserved, but the momentum of each one separately is not conserved.
A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the momentum change during the collision is correct? (There could be more than one correct choice.)
The small car and the truck experience the same magnitude momentum change
A 3.0-kg object moves to the right at 4.0 m/s. It collides head-on with a 6.0-kg object moving to the left at 2.0 m/s. Which statement is correct
The total momentum both before and after the collision is zer
In a collision between two unequal masses, how does the impulse imparted to the smaller mass by the larger mass compare with the impulse imparted to the larger mass by the smaller one?
They are equal.
In a collision between two unequal masses, which mass receives a greater magnitude impulse?
They receive equal impulses.
An elastic collision of two objects is characterized by the following.
Total kinetic energy of the system remains constant, & Total momentum of the system is conserved
An inelastic collision of two objects is characterized by the following.
Total momentum of the system is conserved.
A particle that has zero momentum must also have zero kinetic energy
True
Internal forces cannot change the total momentum of a system.
True
A railroad car of mass m and speed v collides and sticks to an identical railroad car that is initially at rest. After the collision, the kinetic energy of the system
is half as much as before.
Which of the following quantities are units of momentum? (There could be more than one correct choice.)
kg ∙ m/s & N ∙ s
In the figure showing an isolated system, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is >>>>>> >>>>>>>
not possible because momentum is not conserved.
