When a knife is sharpened by placing it on a rotating iron disc, the sparks more tangentially to the disc due to 

Choose the correct option 

The force exerted by the second body on first body is called ___

A large force which acts for a small interval time is called

Change in momentum is same as

Impulse is given by

Both action and reaction are

Impulse force = _____

Which of these can a force acting on an object not change?

The exchange particles for the electromagnetic force are