Question 1

A 50-kg toboggan is coasting on level snow.As it passes beneath a bridge, a 20-kg parcel is dropped straight down and lands in the toboggan.If KE1 is the original kinetic energy of the toboggan and KE2 is the kinetic energy after the parcel has been added, what is the ratio KE2/KE1.

Accepted Answer

A) 0.4 
B) 0.6 
C) 0.7 
D) 0.8 
E) 1

Question 2

The head of a hammer (m = 1.5 kg) moving at 4.5 m/s strikes a nail and bounces back with the same speed after an elastic collision lasting 0.075 s.What is the magnitude of the average force the hammer exerts on the nail?

Accepted Answer

A) 6.8 N 
B) 60 N 
C) 90 N 
D) 180 N 
E) 240 N

Question 3

A 7.30-kg bowling ball strikes a 1.60-kg pin at rest head-on.Before the collision, the velocity of the ball is +6.00 m/s.After the collision, the velocity of the ball is +5.40 m/s.What is the velocity of the pin after the collision?

Accepted Answer

A) +0.6 m/s 
B) +5.4 m/s 
C) +1.2 m/s 
D) +2.7 m/s 
E) +3.2 m/s

Question 4

A 0.2-kg steel ball is dropped straight down onto a hard, horizontal floor and bounces straight up.The ball's speed just before and just after impact with the floor is 10 m/s.Determine the magnitude of the impulse delivered to the floor by the steel ball.

Accepted Answer

A) zero N . s 
B) 2 N . s 
C) 4 N . s 
D) 20 N . s 
E) 200 N . s

Question 5

The drawing shows two 4.5-kg balls located on the y axis at 1.0 and 9.0 m, respectively, and a third ball with a mass 2.3 kg which is located at 6.0 m.What is the location of the center of mass of this system?

Accepted Answer

A) 4.8 m 
B) 5.2 m 
C) 5.6 m 
D) 6.0 m 
E) 6.4 m

Exam 7: Impulse and Momentum

A 50-kg toboggan is coasting on level snow.As it passes beneath a bridge, a 20-kg parcel is dropped straight down and lands in the toboggan.If KE₁ is the original kinetic energy of the toboggan and KE₂ is the kinetic energy after the parcel has been added, what is the ratio KE₂/KE₁.

The head of a hammer (m = 1.5 kg) moving at 4.5 m/s strikes a nail and bounces back with the same speed after an elastic collision lasting 0.075 s.What is the magnitude of the average force the hammer exerts on the nail?

A 7.30-kg bowling ball strikes a 1.60-kg pin at rest head-on.Before the collision, the velocity of the ball is +6.00 m/s.After the collision, the velocity of the ball is +5.40 m/s.What is the velocity of the pin after the collision?

A 0.2-kg steel ball is dropped straight down onto a hard, horizontal floor and bounces straight up.The ball's speed just before and just after impact with the floor is 10 m/s.Determine the magnitude of the impulse delivered to the floor by the steel ball.

The drawing shows two 4.5-kg balls located on the y axis at 1.0 and 9.0 m, respectively, and a third ball with a mass 2.3 kg which is located at 6.0 m.What is the location of the center of mass of this system?