Question

The picture shows a bucket being whirled around in an area of no gravity, with a help of a string with a very high speed. Which of the following options approximately depict correct analogy of motion of bucket with that of the moon?

• A. Tension in string and Gravitational force on moon are pulling forces.
• B. Fixed point of the string and the moon are at their respective focus.
• C. Tension on the bucket and gravitational force on the moon provides centripetal force.
• D. All of the above.

Answer 1

The correct option is D All of the above.

The whirling of the bucket with the help of a string is similar to the orbiting of the Moon around the Earth. Centripetal force makes an object to rotate in a circular motion. The centripetal force in case of the bucket is the tension (The pull of string on the bucket) provided by the string on the bucket. Similarly, the gravitational force between the Moon and the Earth act as the centripetal force for its rotation.
For bucket, motion is purely circular in nature. However, circular motion is a special case of elliptical motion. The two foci of the circle lie at the center.