For passenger comfort the centripetal acceleration on a railway curve must not exceed 0.5 m/s². What is the smallest radius rmin for a curve taken at 120 km/h?
Circular motion worksheet with answers
A small object sits 80 cm from the axis of a disc that turns at a steady 30 revolutions per minute. Find its centripetal acceleration ac.
A car takes a flat curve of radius 125 m. The coefficient of static friction between tyres and road is 0.5. Use g = 9.81 m/s². Find the highest speed vmax at which the car can take the curve without skidding.
A car takes a flat curve of radius 130 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 curve of radius 60 m is banked at 18°, and the coefficient of static friction between tyres and road is 0.4. Use g = 9.81 m/s². Find the highest speed vmax at which a car can take the curve without sliding up and out.
A ball on a string 1.3 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?
Answer key
- 1. rmin = 2222 m
- 2. ac = 7.896 m/s²
- 3. vmax = 24.76 m/s
- 4. vmax = 19.56 m/s
- 5. vmax = 22.15 m/s
- 6. vmin = 3.571 m/s
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