Practice Problems
Momentum and Energy
Directions:
On this worksheet you will be investigating the relationships between momentum and energy.
Question 1
If F
max
= 18 N and F
min
= -11 N then calculate the impulse delivered to a 3-kg mass during the 5 seconds graphed above.
45.5 N sec
34.5 N sec
3 N sec
-9.5 N sec
1.5 N sec
Question 2
If the object's initial velocity in
Question 1
was 8.9 m/sec, what will be its final velocity at the end of these 5 seconds?
28.2 m/sec
5.7 m/sec
3.5 m/sec
-8.4 m/sec
9.4 m/sec
Question 3
What was the magnitude of the average force acting on the 3-kg mass in
Question 1
during the 5 seconds displayed on the graph?
-1.9 N
3.5 N
6.9 N
7.5 N
0.3 N
Question 4
A 8.9-gram bullet moving at 250 m/sec travels through a block of wood and emerges out the other side moving at 230 m/sec. If it takes 29.9 µsecs (1 µsec = 1 x 10
-6
seconds) for the bullet to bore through the wood, what average force did the wood exert on the bullet?
6.85 x 10
4
N
-5.95 x 10
3
N
7.44 x 10
4
N
1.43 x 10
6
N
Question 5
During target practice, a man shoots a 8.9-gram bullet with a horizontal velocity of 230 m/sec at a 1.5-kg wooden block balanced on the top of a 1.1-meter tall fence post. If the bullet embeds in the block, how fast will the block-bullet be knocked off the post?
1.36 m/sec
228.64 m/sec
153.33 m/sec
0.058 m/sec
Question 6
After being knocked off, how far from the base of the fence post will the block in
Question 5
hit the ground?
0.77 m
0.31 m
1.08 m
0.64 m
0.46 m
Question 7
A second 8.9-gram bullet is fired at another 1.5-kg block which is initially at rest on a table. The bullet embeds in the block resulting in the block sliding 165 centimeters before coming to a stop. The coefficient of friction between the block and the table's surface is µ = 0.374.
How much work will the friction between the table and block do on the block while bringing it to a stop?
5.5 J
61.7 J
24.4 J
9.1 J
3.4 J
Question 8
How fast was the original bullet in
Question 7
travelling before it struck the block?
405.8 m/sec
347.3 m/sec
302.9 m/sec
455 m/sec
588.8 m/sec
Question 9
As shown in the diagrams provided below, a ball of mass 1 kg is originally moving along the x-axis with a velocity of 11 m/sec towards the origin. As it approaches the origin, it delivers a glancing blow to a stationary 2-kg mass. After the collision, the 1-kg ball continues traveling towards the left, into the second quadrant, at a reduced speed of 5 m/sec at an angle of 37º above the negative x-axis.
What is the final momentum of the 2-kg mass after the collision?
7.6 kg m/sec
5.5 kg m/sec
7 kg m/sec
3 kg m/sec
15.2 kg m/sec
Question 10
Within the system, what fraction of the 1-kg ball's original KE remains after the collision?
0.8
0.312
0.445
0.198
0.64
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