Force and Laws of Motion — Science STD 9 — Question

• Balanced forces: If the resultant of all the forces acting on a body is zero, the forces are called balanced forces. These forces do not change the state of rest or of uniform motion of a body but can change the shape of the body.

For example: when a balloon is pressed between hands, then balanced forces (equal and opposite forces) act on the balloon due to which the shape of the balloon changes.

• Unbalanced forces: If the resultant of all the forces acting on a body is not zero, the forces are called unbalanced forces. These forces change the state of rest or of uniform motion of a body.

For example: if we push a toy car lying on the ground, it starts moving due to the unbalanced force exerted by our hands.