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 = 16 N and F_min = -11 N then calculate the impulse delivered to a 4-kg mass during the 5 seconds graphed above.
-11.5 N sec43.5 N sec32.5 N sec-1 N sec-0.5 N sec

		Question 2 If the object's initial velocity in Question 1 was 8.1 m/sec, what will be its final velocity at the end of these 5 seconds?
-8.2 m/sec5.2 m/sec8 m/sec1.9 m/sec31.9 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?
-2.5 N6.5 N2.5 N-0.1 N-2.3 N

		Question 4 A 8.1-gram bullet moving at 280 m/sec travels through a block of wood and emerges out the other side moving at 240 m/sec. If it takes 25.7 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?
-1.26 x 10⁴ N8.82 x 10⁴ N1.64 x 10⁶ N7.56 x 10⁴ N

		Question 5 During target practice, a man shoots a 8.1-gram bullet with a horizontal velocity of 240 m/sec at a 2-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?
239.03 m/sec0.067 m/sec0.97 m/sec120 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?
1.13 m0.22 m0.32 m0.8 m0.46 m

		Question 7 A second 8.1-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 168 centimeters before coming to a stop. The coefficient of friction between the block and the table's surface is µ = 0.371. How much work will the friction between the table and block do on the block while bringing it to a stop?
62.3 J4.3 J12.3 J33.1 J7.3 J

		Question 8 How fast was the original bullet in Question 7 travelling before it struck the block?
867.7 m/sec350 m/sec277.8 m/sec615 m/sec436.4 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?

3 kg m/sec7 kg m/sec5.5 kg m/sec15.2 kg m/sec7.6 kg m/sec

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