1. Momentum Packet
Solutions

2. Problem 1
A hockey player makes a slap shot, exerting a constant force of 25.0 N on the puck for 0.16 seconds. What is the magnitude of the impulse given to the puck?
impulse, Dp = FDt
= 25.0 x 0.16
= 4.0 Ns

3. Problem 2
An 8-kilogram bowling ball is rolling in a straight line toward you. If its momentum is 16 kg·m/s, how fast is it traveling?
p = mv
16 = 8 • v
v = 16/8
v = 2 m/s

4. Problem 3
Tiger Woods hits 45.0-gram golf ball, giving it a speed of 75.0 m/sec. What momentum has Tiger given to the golf ball?
p = mv
p = (0.045)(75)
p = 3.375
p = 3.4 Ns

5. Problem 4
A 5.00 kg ball accelerates at a rate of 2.00 m/s2 for 1.50 seconds. Calculate the ball’s momentum after the acceleration. The acceleration equation is assuming the initial velocity is 0 m/s, the equation becomes

6. Problem 5 = 5.00 x 10.0 = 50.0 Ns 50.0 = 2.5 x Dv Dv = 50.0 / 2.50
A constant force of 5.00 N acts on a 2.50 kg object for 10.0 s. What are the changes in the object’s momentum (impulse) and velocity?
Impulse, Dp = FDt
= 5.00 x 10.0
= 50.0 Ns
Impulse, Dp = mDv
50.0 = 2.5 x Dv
Dv = 50.0 / 2.50
= 20.0 m/s

7. Problem 6
A 2.00 kg rock is dropped from the top of a 30.0 m high building. Calculate the ball’s momentum at the time that it strikes the ground (hint: this is a projectile motion problem). Solve for the time it took the rock to hit the ground use the equation vf = vi + at to solve for the final vertical velocity

8. Problem 7
A 1.00 kg rock is thrown up into the air from ground level at a speed of 8.00 m/s. The ball travels up to a maximum height, then returns to the ground. Calculate the rock’s momentum as it strikes the ground (hint: this is a projectile motion problem). “What goes up must come down” and it will come down at the same speed it went up. p = mv p = 1.00 x 8.00 p = 8.00 Ns

9. Problem 8
A 1.50 kg rock is thrown up into the air from ground level, reaches a maximum height of 7.00 m before returning to the ground. Calculate the rock’s momentum as it strikes the ground (hint: this is a projectile motion problem). The velocity of the rock thrown upward is the same as dropping the rock from 7 meters up. Solve for time and use the final velocity to find the vertical velocity of the rock.