Physics chapter 8 concept
You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You can either catch the object or deflect the object back towards your friend (such that it moves away from you with the same speed as it was originally thrown). What should you do in order to MINIMIZE your speed on the skateboard?
Catch the ball
What happens in an elastic collision
Momentum and Kinetic Energy are conserved
A baseball is thrown vertically upward and feels no air resistance. As it is rising
its momentum is not conserved, but its mechanical energy is conserved.
In a collision between two objects having unequal masses, how does magnitude of the impulse imparted to the lighter object by the heavier one compare with the magnitude of the impulse imparted to the heavier object by the lighter one?
Both have the same impulse
As a tile falls from the roof of a building to the ground its momentum is conserved.
False
What happens in an inelastic collision
Momentum is conserved and Kinetic Energy is lost.
Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greatest impact force?
The force would be the same in both cases.
Represents the impulse of the force in a graph of force vs time
The impulse is equal to the area under the curve
A freight car moves along a frictionless level railroad track at constant speed. The freight car is open on the top. A large load of sand is suddenly dumped into the freight car. What happens to the speed of the freight car?
The speed of the freight car decreases.
When a person steps forward out of a small boat onto a dock, the boat recoils backward in the water. Why does this occur?
The total momentum of the system is conserved.
On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction?
momentum and mechanical energy
A small glider is coasting horizontally when suddenly a very heavy piece of cargo falls out of the bottom of the plane. You can neglect air resistance. Just after the cargo has fallen out
neither the cargo nor the plane change speed.
A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring
the lighter block will have more kinetic energy than the heavier block.
A lump of putty and a rubber ball have equal mass. Both are thrown with equal speed against a wall. The putty sticks to the wall. The ball bounces back at nearly the same speed with which it hit the wall. Which object experiences the greater momentum change?
The ball experiences the greater momentum change.
Jacques pushes George's canoe with a force F⃗ to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water?
The final momentum is zero but the final kinetic energy is positive.
A red ball with a velocity of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of −2.0 m/s. What is the velocity of the two balls after the elastic collision?
The velocity of the red ball is −2.0 m/s; the velocity of the yellow ball is +3.0 m/s.
A small car has a head-on collision with a large truck. Which of the following statements concerning the magnitude of the average force due to the collision is correct?
They have the same average force
What does a object's change in momentum depend on?
Time interval, Change in velocity, Magnitude of the force, and mass of object
