For passenger comfort the centripetal acceleration on a railway curve must not exceed 1.2 m/s². What is the smallest radius rmin for a curve taken at 160 km/h?
Circular motion worksheet with answers
A small object sits 60 cm from the axis of a disc that turns at a steady 150 revolutions per minute. Find its centripetal acceleration ac.
A road engineer wants cars to take a curve of radius 120 m at 90 km/h without relying on friction. Use g = 9.81 m/s². Find the banking angle θ.
A car takes a flat curve of radius 30 m. The coefficient of static friction between tyres and road is 0.8. Use g = 9.81 m/s². Find the highest speed vmax at which the car can take the curve without skidding.
A 1.4 kg ball on a string 0.8 m long is swung in a vertical circle. At the lowest point it moves at 6 m/s. Use g = 9.81 m/s². Find the tension T in the string at the lowest point.
A 1.8 kg ball on a string 0.9 m long is swung in a vertical circle. At the lowest point it moves at 3.5 m/s. Use g = 9.81 m/s². Find the tension T in the string at the lowest point.
Answer key
- 1. rmin = 1646 m
- 2. ac = 148 m/s²
- 3. θ = 27.96 °
- 4. vmax = 15.34 m/s
- 5. T = 76.73 N
- 6. T = 42.16 N
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