A 900 kg car drives around a flat curve of radius 140 m at a constant 30 m/s. Find the inward (centripetal) force Fc needed.
Circular motion worksheet with answers
A small object sits 40 cm from the axis of a disc that turns at a steady 200 revolutions per minute. Find its centripetal acceleration ac.
A small ball on a string of length 1.6 m moves in a horizontal circle so that the string makes a constant angle of 15° 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 75 m. The coefficient of static friction between tyres and road is 0.5. 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 string 1.4 m long is swung in a vertical circle. At the lowest point it moves at 9 m/s. Use g = 9.81 m/s². Find the tension T in the string at the lowest point.
A ball on a string 0.7 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. Fc = 5786 N
- 2. ac = 175.5 m/s²
- 3. v = 1.043 m/s
- 4. vmax = 19.18 m/s
- 5. T = 20.3 N
- 6. vmin = 2.62 m/s
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