Conservative and Non-conservative Forces

Work done during the motion of a body on a closed loop is zero for every force in nature. Is it true?

Comet moves around the sun in highly elliptical orbits. The gravitational force on the comet due to the sun is not normal to the comet's velocity in general. Yet the work done by the gravitational force over every complete orbit of the comet is zero. Why?

When we lift or push something, our body muscles exert forces. Are these forces conservative?

Is frictional force a conservative force or a non-conservative force? Why is it called so?

Distinguish between a conservative force and a non-conservative force.

What is the potential energy associated with a non-conservative force?

Which of the following forces is not conservative?

In a gravitational force field a particle is taken from $A$   to $B$ along different paths as shown in figure. Then

Which of the following statement is not true?

The potential energy of a system increases if work is done

Write three different statements for defining a conservative force.

Example of a non-conservative force is:

A curved surface is shown in figure. The portion $BCD$ is frictionless. There are two spherical balls of identical radii and masses, balls are released from rest one by one from $A$ which is at a slightly greater height than $C$. With the surface $AB$, ball $1$ has a small friction and ball $2$ has a negligible friction. For which balls is total mechanical energy conserved?

Identify the false statement from the following.

If w₁, w₂ and w₃ represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively(as shown)in the gravitational field of a point mass m. Find the correct relation between w₁, w₂ and w₃

Which of the following is/are conservative force(s) ?

Choose the incorrect statement