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Circular Motion – Worksheet 1
1. A 0.020 kg mass in undergoing uniform circular motion in a 0.30 m radius circle. The
circle is horizontal. If the frequency is 5 Hz, find the
a) period
b) speed
c) centripetal acceleration
d) centripetal force
2. A 2 kg mass is attached to an 80 cm string. The mass is traveling around the horizontal
circle, with the string fixed at the center, in a period of 0.25 seconds. Find the
a) speed
b) frequency
c) centripetal acceleration
d) centripetal force
e) what supplies the Fc?
3. A 1600 kg car is rounding a 30 m radius corner on flat ground. If the speed of the car is a
uniform 7 m/s, find the
a) centripetal acceleration
b) centripetal force
c) what supplies the Fc?
4. A 1300 kg race car has a force of friction of 900 N between the tires and the road. If the
driver maintains a uniform speed of 4 m/s, how tight of a turn can he make? (find the
radius of the circle)
5. A mass is undergoing uniform circular motion in a clockwise direction.
Find the direction of the centripetal acceleration and the direction of the
velocity if the string breaks at the points indicated.
6/28/2017
6. A girl swings a bucket of water of mass 4 kg in a vertical circle. If she swings it at constant
speed, with a frequency of 0.7 Hz, and the rope + bucket is 0.75 m long,
a) what is the period of the loop?
b) what is speed of the bucket?
c) what is the force in the rope at the top of the loop?
d) what is the force in the rope at the bottom of the loop?
7. A 750 kg roller coaster car + passengers goes around a vertical loop of radius 10 m. If it
reaches a speed of 25 mph at the top (11.2 m/s), what is the force provided by the track?
8. For the coaster in problem 7, what is the minimum speed the coaster could go if the
coaster is not “attached” to the track? That is, what is the critical velocity of the coaster?
(Ftrack=0 N)
9. What is the force of the track when the 750 kg coaster reaches the bottom of the 10 m
radius loop if it is now traveling 22.7 m/s?
Answers:
1a) 0.2 sec, b) 9.42 m/s, c) 296 m/s², d) 5.92 N, 2a) 20.1 m/s, b) 4 Hz, c) 505 m/s², d)
1010 N, e) the string (FT), 3a) 1.63 m/s², b) 2610 N, c) friction (Ff), 4. 23.1m, 5. xx, 6. a)
1.43 sec, b) 3.30 m/s, c) 18.9 N [down], d) 97.3 N [up], 7 2060 N [down], 8. 9.90 m/s, 9.
46 000 N [up]