A small object sits 20 cm from the axis of a disc that turns at a steady 150 revolutions per minute. Find the speed v of the object.
Circular motion worksheet with answers
A 0.9 kg stone is whirled in a horizontal circle of radius 1.8 m on a smooth, level table, held by a string that breaks at a tension of 20 N. Find the highest speed vmax the stone can have.
In a fairground rotor, riders stand against the wall of a vertical cylinder of radius 1.7 m. When it spins fast enough the floor drops away and friction holds them up. The coefficient of static friction is 0.7. Use g = 9.81 m/s². Find the smallest angular speed ω in rad/s.
A car takes a flat curve of radius 75 m. The coefficient of static friction between tyres and road is 0.3. Use g = 9.81 m/s². Find the highest speed vmax at which the car can take the curve without skidding.
A ball on a string 0.9 m long is swung in a vertical circle. Use g = 9.81 m/s². What is the smallest speed vmin at the top for which the string just stays tight?
A curve of radius 140 m is banked at 30°, and the coefficient of static friction between tyres and road is 0.1. Use g = 9.81 m/s². Find the highest speed vmax at which a car can take the curve without sliding up and out.
Answer key
- 1. v = 3.142 m/s
- 2. vmax = 6.325 m/s
- 3. ω = 2.871 rad/s
- 4. vmax = 14.86 m/s
- 5. vmin = 2.971 m/s
- 6. vmax = 31.42 m/s
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