**Chapter 11 Practice 1**

At what speed do a bicycle and its rider, with a combined mass of 120 kg , have the same momentum as a 1800 kg car traveling at 5.8 m/s ?

87 m/s

A 2.0 kg object is moving to the right with a speed of 3.5 m/s when it experiences the force shown in the figure. What are the object’s speed and direction after the force ends?

2.5 m/s right

A tennis player swings her 1000 g racket with a speed of 11.0 m/s . She hits a 60 g tennis ball that was approaching her at a speed of 20.0 m/s . The ball rebounds at 44.0 m/s .

How fast is her racket moving immediately after the impact? You can ignore the interaction of the racket with her hand for the brief duration of the collision.

7.16 m/s

If the tennis ball and racket are in contact for 10.0 ms , what is the average force that the racket exerts on the ball?

384 N

A 5500 kg open train car is rolling on frictionless rails at 25 m/s when it starts pouring rain. Rain falls vertically. A few minutes later, the car's speed is 23 m/s . What is the mass of water collected?

480 kg

A 620-g object traveling at 2.1 m/s collides head-on with a 320-g object traveling in the opposite direction at 3.8 m/s. If the collision is perfectly elastic, what is the change in the kinetic energy of the 620-g object?

-.228 J

What is the final velocity of the 320-g object?

And its change in kinetic energy?

.228J

3.98 m/s

A 480-kg car moving at 14.4 m/s hits from behind a 570-kg car moving at 13.3 m/s in the same direction. If the new speed of the heavier car is 14.0 m/s, what is the speed of the lighter car after the collision, assuming that any unbalanced forces on the system are negligibly small?

13.6 m/s

A 2.00-kg object traveling east at 20.0 m/s collides with a 3.00-kg object traveling west at 10.0 m/s. After the collision, the 2.00-kg object has a velocity 5.00 m/s to the west. How much kinetic energy was lost during the collision?

458 J

A proton is traveling to the right at 2.0×10^7 m/s. It has a head-on perfectly elastic collision with a carbon atom. The mass of the carbon atom is 12 times the mass of the proton. What are velocities of each after the collision?

-1.69 x 10^7 m/s

3.08 x 10^6 m/s

A package of mass m is released from rest at a warehouse loading dock and slides down the h = 2.4 m - high, frictionless chute to a waiting truck. Unfortunately, the truck driver went on a break without having removed the previous package, of mass 2m, from the bottom of the chute.

Suppose the packages stick together. What is their common speed after the collision?

Suppose the collision between the packages is perfectly elastic. To what height does the package of mass m rebound?

.27 cm

2.3 m/s

Can you explain Stop and Think 11.3?

Could you explain more on how to use the equations for elastic collisions?

What type of collision is this?

I don't really understand elastic/ inelastic and what that actually means.