5.2 – Centripetal Acceleration and Force
1. A car turns a circular curve with a speed of 20 m/s. If the radius of the curve is 100m, calculate the
centripetal acceleration of the car. [4.0m/s2]
2. You throw a Frisbee to your friend. The Frisbee has a diameter of 28.0 cm and
makes one turn in 0.110 s. What is the centripetal acceleration at its outer edge?
[4.57 X 102 m/s2]
3. A child playing with a top spins it so that it has a centripetal acceleration of 125.0 m/s2 at the edge, a
distance of 3.00 cm from the axis of rotation. What is the speed at the edge of the top? [1.94 m/s]
4. A helicopter blade has a diameter of 14.0 m and a centripetal acceleration at the tip of
2527.0 m/s2. What is the period of the helicopter blade? [0.331 s]
5. Determine the magnitude of the centripetal acceleration for a rock being whirled in a circle, at the end of a
1.5 m string, on a smooth sheet of ice, with a frequency of 1.25 Hz. [93 m/s2]
6. Newer hard drives can spin at a maximum rate of 4200 rpm and
reduce power consumption. The hard drive has a diameter of 2.16
cm. Calculate the magnitude of the centripetal acceleration on the
outside radius of the spinning hard drive disk. [2.09 X 103 m/s2]
7. A 25.0 kg child is pushed by her friend on a merry-go round. She is 1.10 m from the centre of the merrygo-round and required 1.30 seconds to make one complete revolution. Determine the magnitude of the
centripetal force acting on her. [642 N]
8. Identify the force(s) behaving as a centripetal force for each situation described?
a) A satellite going around the Earth.
b) A car travelling around a level corner.
c) A rat named Basil on a string flying around in a horizontal circle.
9. A 50 g set of keys is swung in a circle on the end of a 90 cm long lanyard at a speed of 5.9 m/s. Calculate
the magnitude of the centripetal acceleration and centripetal force acting on the keys. [1.9 N]
10. When a car turns a corner on an icy street it must have enough friction between its tires and the road
surface to give it a turning radius identical to the road’s radius of curvature. If the force of friction is less
than the necessary centripetal force, the car will complete a larger radius and may not stay on the road.
Draw an arrow on the car in the diagram indicating its direction of travel if I lost all traction at the point
the car is shown in the diagram and describe why this happens.
11. Using a centrifuge with a rotor radius of 1.00 m and a rotational speed of 500 m/s
determine the
a) Magnitude of the centripetal acceleration [2.50 X 105 m/s2]
b) Frequency of rotation [79.6 Hz]
12. A 1000 kg car enters a level curve at 20 m/s. If the curve has a radius of 80 m, calculate the centripetal
force the must be supplied by friction to keep the car travelling around the radius. [5.0 X 103 N]
13. A day may be defined in a different ways. For example, the Earth’s sidereal day is the
time for one rotation about its axis and is 23 hours 56 minutes long compared to a
solar day of 24 hours. Using Earth’s average radius of 6.37 X 106 m and the sidereal
day determine the
a) Tangential velocity at the Earth’s equator. [464 m/s]
b) Centripetal force a 60 kg person experiences at the equator [2.0 N]