For passenger comfort the centripetal acceleration on a railway curve must not exceed 1 m/s². What is the smallest radius rmin for a curve taken at 240 km/h?
Circular motion worksheet with answers
A 0.8 kg stone is whirled in a horizontal circle of radius 1.2 m on a smooth, level table, held by a string that breaks at a tension of 200 N. Find the highest speed vmax the stone can have.
A small ball on a string of length 0.8 m moves in a horizontal circle so that the string makes a constant angle of 60° with the vertical (a conical pendulum). Use g = 9.81 m/s². Find the speed v of the ball.
A car takes a flat curve of radius 35 m. 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 the car can take the curve without skidding.
A curve of radius 100 m is banked at 20°, and 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 a car can take the curve without sliding up and out.
A ball on a string 0.8 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 = 4444 m
- 2. vmax = 17.32 m/s
- 3. v = 3.431 m/s
- 4. vmax = 11.72 m/s
- 5. vmax = 27.04 m/s
- 6. vmin = 2.801 m/s
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