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 = 15 N and F_min = -11 N then calculate the impulse delivered to a 4-kg mass during the 5 seconds graphed above.
-12.5 N sec42.5 N sec-3 N sec-1.5 N sec31.5 N sec

		Question 2 If the object's initial velocity in Question 1 was 8.5 m/sec, what will be its final velocity at the end of these 5 seconds?
-8.9 m/sec32.5 m/sec1.8 m/sec5.4 m/sec8.1 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 N6.3 N-7.5 N2 N-0.3 N

		Question 4 A 8.5-gram bullet moving at 280 m/sec travels through a block of wood and emerges out the other side moving at 200 m/sec. If it takes 26.9 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?
8.85 x 10⁴ N6.32 x 10⁴ N-2.53 x 10⁴ N1.52 x 10⁶ N

		Question 5 During target practice, a man shoots a 8.5-gram bullet with a horizontal velocity of 200 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?
0.85 m/sec199.15 m/sec100 m/sec0.085 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?
0.28 m0.19 m0.67 m0.4 m0.94 m

		Question 7 A second 8.5-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 177 centimeters before coming to a stop. The coefficient of friction between the block and the table's surface is µ = 0.38. How much work will the friction between the table and block do on the block while bringing it to a stop?
4.2 J34.8 J7.5 J13.2 J67.3 J

		Question 8 How fast was the original bullet in Question 7 travelling before it struck the block?
302 m/sec362.5 m/sec856.7 m/sec447.9 m/sec660 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/sec7 kg m/sec5.5 kg m/sec15.2 kg m/sec3 kg m/sec

		Question 10 Within the system, what fraction of the 1-kg ball's original KE remains after the collision?
0.80.4450.1980.3120.64