Legend

 ac = centripetal acceleration v = velocity r = radius Fc = centripetal force m = mass FN = normal force Ff = force of friction Fg = force of gravity

The swing ride at amusement parks makes use of circular motion.

Problems

 Before you start the Problems, be sure to have a pen/pencil and paper for working out the problems, and also a calculator.  If you want to use our java calculator:

1) An object of mass m is on a horizontal rotating platform.  The mass is located 0.22 m from the center and makes one revolution every 0.74 s.  The friction force needed to keep the mass from sliding is 13 N.  What is the object's mass?

 kg

2) An object travels along a path at constant speed.  There is a constant net force acting on the object that remains perpendicular to the direction of the motion.   Describe the path of the object.
a) linear
b) circular
c) elliptical
d) parabolic

3) A child is riding on a merry-go-round rotating at a constant rate.  Which of the following describes the child's speed, velocity, and magnitude of acceleration?

 speed velocity acceleration a) constant constant constant b) constant changing constant c) changing constant changing d) changing changing changing

4) A 150 g ball at the end of a string is revolving uniformly in a horizontal circle of radius 0.600 m.  the ball makes exactly 2.00 revolutions in a second.  What is its centripetal acceleration?

 m/s2

5) How large must the coefficient be between the tires and the road if a car is to round a level curve of radius 95 m at a speed of 90 km/h?

6) A ball attached to a string swings in a circle of radius 1.20 m at 28o angle with the vertical.  The tension in the string is 1.80 N.

a) What is the mass of the ball?
b) How long does the ball take to complete one orbit?

 a) kg b) s

7) A 35 kg child spins in a 12 m radius vertical Ferris Wheel moving at constant speed; it completes a full rotation every 9 seconds.

a) as the child reaches the top, what is the magnitude of the force that the seat exerts on the child?
b) the magnitude of the child's acceleration at the top of the ride compared to the child's acceleration at the bottom:
a) less than the bottom
b) greater than the bottom
c) same

 a) N b)
 RESULTS

 Formulas Gravitation