Practice Problems
Momentum and Energy
Directions:
On this worksheet you will be investigating the relationships between momentum and energy.
Question 1
If F
max
= 17 N and F
min
= -13 N then calculate the impulse delivered to a 3-kg mass during the 5 seconds graphed above.
36.5 N sec
-2.5 N sec
-15.5 N sec
49.5 N sec
-5 N sec
Question 2
If the object's initial velocity in
Question 1
was 6.4 m/sec, what will be its final velocity at the end of these 5 seconds?
1.2 m/sec
1.3 m/sec
-7.2 m/sec
16.7 m/sec
5.6 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?
-0.5 N
-12.5 N
-3.1 N
7.3 N
2 N
Question 4
A 6.4-gram bullet moving at 290 m/sec travels through a block of wood and emerges out the other side moving at 220 m/sec. If it takes 26.5 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?
5.31 x 10
4
N
-1.69 x 10
4
N
7 x 10
4
N
1.23 x 10
6
N
Question 5
During target practice, a man shoots a 6.4-gram bullet with a horizontal velocity of 220 m/sec at a 1.5-kg wooden block balanced on the top of a 1.3-meter tall fence post. If the bullet embeds in the block, how fast will the block-bullet be knocked off the post?
146.67 m/sec
0.044 m/sec
219.07 m/sec
0.93 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?
0.25 m
0.8 m
1.13 m
0.48 m
0.34 m
Question 7
A second 6.4-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 168 centimeters before coming to a stop. The coefficient of friction between the block and the table's surface is µ = 0.355.
How much work will the friction between the table and block do on the block while bringing it to a stop?
24.8 J
59.6 J
5.2 J
8.8 J
3.1 J
Question 8
How fast was the original bullet in
Question 7
travelling before it struck the block?
804.5 m/sec
440 m/sec
341.8 m/sec
214.4 m/sec
421.9 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 13 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?
3 kg m/sec
19 kg m/sec
6.5 kg m/sec
9.5 kg m/sec
9 kg m/sec
Question 10
Within the system, what fraction of the 1-kg ball's original KE remains after the collision?
0.562
0.415
0.172
0.75
0.244
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