For passenger comfort the centripetal acceleration on a railway curve must not exceed 0.8 m/s². What is the smallest radius rmin for a curve taken at 200 km/h?
Circular motion worksheet with answers
A 1000 kg car drives around a flat curve of radius 70 m at a constant 10 m/s. Find its centripetal acceleration ac.
A road engineer wants cars to take a curve of radius 130 m at 60 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 25 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 0.3 kg ball on a light string 0.9 m long is swung in a vertical circle. At the lowest point its speed is 12 m/s. Ignore air resistance and use g = 9.81 m/s². Find the tension Ttop in the string at the highest point.
A 1 kg ball on a string 1.2 m long is swung in a vertical circle. At the lowest point it moves at 7.5 m/s. Use g = 9.81 m/s². Find the tension T in the string at the lowest point.
Answer key
- 1. rmin = 3858 m
- 2. ac = 1.429 m/s²
- 3. θ = 12.29 °
- 4. vmax = 14.01 m/s
- 5. Ttop = 33.28 N
- 6. T = 56.69 N
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