Laws of Motion — Physics STD 11 Science — Question

The earth moving round the sun in circular orbit is acted upon by a force and hence work must be done on the earth by the force. Explain.

The sign of work done by a force on a body is important to understand. State carefully if the following quantities are positive or negative:
Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket.

A bullet of mass 20g enters into a fixed wooden block with a speed of 40ms^-1 and stops in it. Find the change in internal energy during the process.

A simple pendulum of length l suspended from a roof of a trolley which moves in a horizontal direction with an acceleration a. Find its time period of oscillation.

Why does cotton wick keep burning in an oil filled lamp?

Give the standard definition of 1 second of time

Obtain the dimensional formula for coefficient of viscosity.

Why does a soft plastic bag weigh the same when empty as when filled with air at atmospheric pressure?

Does the components of a vector quantity depends on frame of reference chosen?

Fundamental frequency of oscillation of a close pipe is 400Hz. What will be the fundamental frequency of oscillation of an open pipe of same length?