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 240 km/h?
Circular motion worksheet with answers
A 1400 kg car drives around a flat curve of radius 200 m at a constant 20 m/s. Find its centripetal acceleration ac.
A road engineer wants cars to take a curve of radius 70 m at 60 km/h without relying on friction. Use g = 9.81 m/s². Find the banking angle θ.
A small ball on a string of length 2 m moves in a horizontal circle so that the string makes a constant angle of 40° with the vertical (a conical pendulum). Use g = 9.81 m/s². Find the speed v of the ball.
A 3.5 kg cart is released from rest at a height of 15 m on a frictionless track and runs through a vertical loop of radius 3 m. Use g = 9.81 m/s². Find the normal force Nbottom of the track on the cart at the bottom of the loop.
A 1.6 kg ball on a light string 0.5 m long is swung in a vertical circle. At the lowest point its speed is 7.5 m/s. Ignore air resistance and use g = 9.81 m/s². Find the tension Ttop in the string at the highest point.
Answer key
- 1. rmin = 8889 m
- 2. ac = 2 m/s²
- 3. θ = 22.02 °
- 4. v = 3.253 m/s
- 5. Nbottom = 377.7 N
- 6. Ttop = 101.5 N
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