For passenger comfort the centripetal acceleration on a railway curve must not exceed 1.5 m/s². What is the smallest radius rmin for a curve taken at 160 km/h?
Circular motion worksheet with answers
An 800 kg car drives around a flat curve of radius 80 m at a constant 12 m/s. Find its centripetal acceleration ac.
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 45° 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 140 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 0.5 kg cart is released from rest at a height of 38 m on a frictionless track and runs through a vertical loop of radius 9.5 m. Use g = 9.81 m/s². Find the normal force Ntop of the track on the cart at the top of the loop.
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 = 1317 m
- 2. ac = 1.8 m/s²
- 3. v = 2.356 m/s
- 4. vmax = 23.44 m/s
- 5. Ntop = 14.71 N
- 6. vmin = 3.571 m/s
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