Momentum and Energy

Practice Problems
Momentum and Energy

Directions: On this worksheet you will be investigating the relationships between momentum and energy.

		Question 1 If F_max = 20 N and F_min = -12 N then calculate the impulse delivered to a 4-kg mass during the 5 seconds graphed above.
38 N sec-10 N sec50 N sec4 N sec2 N sec

		Question 2 If the object's initial velocity in Question 1 was 7.7 m/sec, what will be its final velocity at the end of these 5 seconds?
2.4 m/sec32.8 m/sec5.2 m/sec8.2 m/sec-7.2 m/sec

		Question 3 What was the magnitude of the average force acting on the 4-kg mass in Question 1 during the 5 seconds displayed on the graph?
10 N-2 N4 N0.4 N7.6 N

		Question 4 A 7.7-gram bullet moving at 270 m/sec travels through a block of wood and emerges out the other side moving at 220 m/sec. If it takes 29.3 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?
-1.31 x 10⁴ N7.1 x 10⁴ N5.78 x 10⁴ N1.29 x 10⁶ N

		Question 5 During target practice, a man shoots a 7.7-gram bullet with a horizontal velocity of 220 m/sec at a 2-kg wooden block balanced on the top of a 1.2-meter tall fence post. If the bullet embeds in the block, how fast will the block-bullet be knocked off the post?
110 m/sec219.16 m/sec0.84 m/sec0.07 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?
1.08 m0.29 m0.77 m0.42 m0.21 m

		Question 7 A second 7.7-gram bullet is fired at another 2-kg block which is initially at rest on a table. The bullet embeds in the block resulting in the block sliding 172 centimeters before coming to a stop. The coefficient of friction between the block and the table's surface is µ = 0.395. How much work will the friction between the table and block do on the block while bringing it to a stop?
7.8 J4.5 J33.8 J67.9 J13.4 J

		Question 8 How fast was the original bullet in Question 7 travelling before it struck the block?
365.4 m/sec952.6 m/sec670 m/sec460.3 m/sec275.7 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 12 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?

8 kg m/sec3 kg m/sec17 kg m/sec6 kg m/sec8.5 kg m/sec

		Question 10 Within the system, what fraction of the 1-kg ball's original KE remains after the collision?
0.4240.180.7710.2660.594