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Momentum Worksheet - #1
Impulse-Momentum
J = Ft
p = mv
(Units are NS)
(Units are Kg*m/s)
Impulse = Force x Time
Momentum = Mass x Velocity
Ft = mv or Ft = p
Impulse produces a change in momentum. If you apply a force to an object for a
period of time, its velocity will change. The larger the force or the longer the time,
the greater the change in its momentum.
Newton originally expressed his second law of motion (F = ma) in terms of the rate
of change of momentum:
F = p/t
1. What will be the momentum of a 1250 Kg automobile moving with a velocity of
23 m/s? (28,800 kg m/s)
2. How fast must a 3.50 kg bowling ball move in order to have a momentum of 44.8
kg m/s? (12.8 m/s)
3. A 500 kg mass is at rest and is free to move. At a certain time, 25.0 s after a force
acts on it, the mass has a velocity in the direction of the force of 150 m/s. What is
the magnitude of the force? (3000 N)
4. A 3.50 kg stone is sliding on a horizontal frictional surface with a speed of 14.0
m/s. What is the magnitude of the impulse that must be given to the stone to bring
it to rest? ( -49 kg*m/s)
5. A tennis player practices against a backboard, hitting the ball to the board with a
speed of 22.0 m/s. The ball bounces straight back from board with a speed of 19.0
m/s. The mass of the ball is 55 grams. What is the average force that the wall
exerts on the ball if the ball is in contact with the wall for 1.25 ms? (1804 N)
6. A 160,000 kg DC-8 airplane is flying at 870 km/h. Find its momentum. If each of
the four engines develops a thrust of 350 kN, how much time is needed for the
airplane to reach this speed? (3.9 X 107 Kg*m/s, 28 s)