Name a machine for each of the following use :
(a) to multiple the force,
(b) to change the point of application of force,
(c) to change the direction of force,
(d) to obtain the gain in speed.

Name a machine which is used to : (a) multiply force, (ii) multiply speed, and (c) change the direction of force applied.

Name a machine which can be used to : change the direction of force applied.

Give one example of the following case where a force : changes the shape of a body

(A) : No two electric lines of force can intersect each other (R ): Tangent at any point of electric line of force gives the direction of electric field.

Which of the following forces can cause a change in the potential energy?

In the following figure, if magnitude of forces between B and C is F, then magnitude of force between A and B is

A machine works as a (i) force multiplier, (ii) speed multiplier. In each case state whether the velocity ratio is more than or less than 1.

A piece of stone tied at the end of a thread is whirled in a horizontal circle with uniform speed by hand, Answer the following questions (a) Is the velocity of stone uniform or variable? (b ) Is the acceleration of stone uniform or variable? ( c) What is the direction of acceleration of stone at any instant? (d) which force provides the centripetal force required for circular motion? (e) Name the force and its direction which acts on the hand.

The figure alongside shows an axle AB pivoted at a point 0. Draw diagrams showing the point of application and direction of minimum force to rotate it (b) clockwise, and (ii) anticlockwise.