UNIFORM CIRCULAR MOTION
1. A rubber ball moves in a circular path of radius 100cm. It makes two revolutions per
second.
Calculate:
a) period of revolution
b) speed of the ball
c) centripetal acceleration
2. A stone is attached to a string 1.00m long, and is twirled in a circle at a rate of 15
revolutions in 20 seconds. Calculate the centripetal acceleration acting on the stone.
3. A phonograph record 60.0cm in diameter rotates 33
1/3 times per minute.
a) What is its period?
b) Calculate the speed of a point on its rim in m/s.
c) What is the centripetal acceleration of a point on it
rim?
4. An object moves with uniform circular motion in a circle of radius 1.50 metres, and
makes 5 revs in 10 seconds. What centripetal acceleration is acting on the object?
5.
An object is moving with uniform circular motion, at a speed of 5.00 m/s. The
centripetal acceleration that is acting on it is 20.0 m/s2.
a) Calculate the radius of its orbit.
b) Calculate it period.
6. An object which moves in a circular path is acted upon by a centripetal acceleration
of 12.0 m/s2. It makes 4 revs in 10 seconds.
a) Calculate the radius of its orbit.
b) Calculate the speed at which the object is moving.
7. An object of mass 2.50 kg is tied to the end of a string 0.80 m long, and is swung in
a horizontal circle with UCM such that it makes 8.00 revs in 6.00 seconds. Find:
a) Period
b) velocity
c) centripetal acceleration
d) tension in the string
8. A string can withstand up to 15.0 kg hung vertically on it, and then it will break. A
piece of this string 2.0m long is used to whirl a 0.50 kg mass in a horizontal circle
faster until it breaks. Find:
a) Breaking force of the string
b) Max. speed reached before the string breaks
c) Period of this motion
d) Frequency at this time.
9. A 0.400 kg body moves with UCM in a vertical circle of radius1.20 m, with period T=
0.300 seconds. Find:
a) Speed of the object
b) Centripetal force needed to maintain this motion
c) String tension when the mass is at the bottom
d) String tension when the mass is at the top.
10. An object of mass 1.80 kg is tied to the end of a string 0.600 m long, and is swung
in a horizontal circle with UCM such that it makes 5 revs in 3.25 seconds. Find:
a) Period
b) Velocity
c) Centripetal acceleration
d) Tension in string
11. A string can withstand up to 60.0 kg hung vertically on it before it will break. A
piece of this string 3.00 m long is used to whirl a 4.00 kg mass in a horizontal circle
faster and faster until it breaks. Find:
a) Breaking force
b) Max speed reached before the string breaks
c) Period of this motion
d) Frequency of this motion
12. A 2.50 kg body moves with UCM in a vertical circle of radius 1.80m and period T=
0.750 seconds. Find:
a) Speed of the object in its orbit.
b) Centripetal force needed to maintain this motion
c) String tension when the mass is at the bottom
d) String tension when the mass is at the top.
Answers
1. a) 0.5s
2. 22.3 m/s2
3. a) 1.8s
4. 14.8 m/s2
5. a) 1.25 m
6. a) 1.9 m
7. a) 0.75 s
8. a) 147 N
9. a) 25.1 m/s
10. a) 0.65 sec
11. a) 588 N
12. a) 15.1 m/s
b) 12.6 m/s
c) 158 m/s2
b) 1.05 m/s
c) 3.66 m/s2
b) 1.57 s
b) 4.8 m/s
b) 6.7 m/s
b) 24.2 m/s
b) 211 N
b) 5.8 m/s
b) 21 m/s
b) 317 N
c) 56.1 m/s2
c) 0.518 s
c) 215 N
c) 56.1 m/s2
c) 0.9 sec
c) 341.5 N
d) 140 N
d) 1.93 Hz
d) -207 N
d) 101 N
d) 1.11 Hz
d) -292.5 N