[" 1.When do we say that work is "],[" done? "]

(a) When do we say that work is done ? Write the formula for the work done by a body in moving up against gravity. Give the meaning of each symbol which occurs in it. (b) How much work is done when a force of 2 N moves a body through a distance of 10 cm in the direction of force?

From scientific point of view,when do we say that no work was done?

Study the pictures given below and answer the questions: From scientific point of view, when do we say that no work was done?

Why do we say that stone is a solid ?

Answer the following : In the figure alongside , a string , attached to a wooden block on a table , is passed over a pully and tied to a weight . On applying a sufficient weight, the block will be seen to move : When can we say that work is done by the applied force ?:

When do you say that body has done no work?

When can we say that an object is in motion?

When do we say that there is an electric current in a conductor ?

When do we say two vectors are orthogonal?