A 900 kg car drives around a flat curve of radius 140 m at a constant 15 m/s. Find the inward (centripetal) force Fc needed.
Circular motion worksheet with answers
A small object sits 140 cm from the axis of a disc that turns at a steady 200 revolutions per minute. Find the speed v of the object.
In a fairground rotor, riders stand against the wall of a vertical cylinder of radius 3.7 m. When it spins fast enough the floor drops away and friction holds them up. The coefficient of static friction is 0.3. Use g = 9.81 m/s². Find the smallest rotation rate n in revolutions per minute.
A small ball on a string of length 1.4 m moves in a horizontal circle so that the string makes a constant angle of 30° with the vertical (a conical pendulum). Use g = 9.81 m/s². Find the speed v of the ball.
A curve of radius 270 m is banked at 18°, and the coefficient of static friction between tyres and road is 0.2. Use g = 9.81 m/s². Find the highest speed vmax at which a car can take the curve without sliding up and out.
A 1.3 kg ball on a light string 1.2 m long is swung in a vertical circle. At the lowest point its speed is 8 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. Fc = 1446 N
- 2. v = 29.32 m/s
- 3. n = 28.39 rpm
- 4. v = 1.991 m/s
- 5. vmax = 38.56 m/s
- 6. Ttop = 5.568 N
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