Circular Motion Physics - Circular Motion

A stone is fastened to one end of a string and is whirled in a vertical circle of radius R. Find the minimum speed the stone can have at the highest point of the circle.

A scooter weighing 150kg together with its rider moving at 36km/ hr is to take a turn of radius 30m. What horizontal force on the scooter is needed to make the turn possible?

A heavy mass m is hanging from a string in equilibrium without breaking it. When this same mass is set into oscillation, the string breaks. Explain.

You are driving a motorcycle on a horizontal road. It is moving with a uniform velocity. Is it possible to accelerate the motoreyle without putting higher petrol input rate into the engine?

A circular road of radius 50m has the angle of banking equal to 30°. At what speed should a vehicle go on this road so that the friction is not used?

The bob of a simple pendulum of length 1m has mass 100g and a speed of 1.4m/s at the lowest point in its path. Find the tension in the string at this instant.

Consider the circular motion of the earth around the sun. Which of the following statements is more appropriate?

1. Gravitational attraction of the sun on the earth is equal to the centripetal force.
2. Gravitational attraction of the sun on the earth is the centripetal force.

Find the acceleration of the moon with respect to the earth from the following data:
Distance between the earth and the moon = 3.85 × 10⁵km and the time taken by the moon to complete one revolution around the earth = 27.3 days.

If the horizontal force needed for the turn in the previous problem is to be supplied by the normal force by the road, what should be the proper angle of banking?

A ceiling fan has a diameter (of the circle through the outer edges of the three blades) of 120cm and rpm 1500 at full speed. Consider a particle of mass 1g sticking at the outer end of a blade. How much force does it experience when the fan runs at full speed? Who exerts this force on the particle? How much force does the particle exert on the blade along its surface?

Find the acceleration of a particle placed on the surface of the earth at the equator due to earth's rotation. The diameter of earth = 12800km and it takes 24 hours for the earth to complete one revolution about its axis.

A bird while flying takes a left turn, where does it get the centripetal force from?

Some washing machines have cloth driers. It contains a drum in which wet clothes are kept. As the drum rotates, the water particles get separated from the cloth. The general description of this action is that "the centrifugal force throws the water particles away from the drum". Comment on this statement from the viewpoint of an observer rotating with the drum and the observer who is washing the clothes.

A car driver going at some speed v suddenly finds a wide wall at a distance r. Should he apply brakes or turn the car in a circle of radius r to avoid hitting the wall?

After a good meal at a party you wash your hands and find that you have forgotten to bring your handkerchief. You shake your hands vigorously to remove the water as much as you can. Why is water removed in this process?

A person stands on a spring balance at the equator.

1. By what fraction is the balance reading less than his true weight?
2. If the speed of earth's rotation is increased by such an amount that the balance reading is half the true weight, what will be the length of the day in this case?

A track consists of two circular parts ABC and CDE of equal radius 100m and joined smoothly as shown in figure. Each part subtends a right angle at its centre. A cycle weighing 100 kg together with the rider travels at a constant speed of 18km/h on the track.

1. Find the normal contact force by the road on the cycle when it is at B and at D.
2. Find the force of friction exerted by the track on the tyres when the cycle is at B, C and D.
3. Find the normal force between the road and the cycle just before and just after the cycle crosses C.
4. What should be the minimum friction coefficient between the road and the tyre, which will ensure that the cyclist can move with constant speed? Take g= 10m/s².