Analysing Momentum

The momentum of an object is the product of its mass and its velocity.

p = m X v

The principles of conservation of liner momentum states that the total linear momentum of a closed system is constant.

The linear momentum before and after a collision is conserved if there is no external force acting on it.

Elastic collision: linear momentum, kinetic energy and total energy are conserved.

Inelastic collision: only linear momentum and total energy are conserved and there is a loss in kinetic energy.

In an EXPLOSION, where two objects move in opposite directions, the total linear momentum before and after the explosion is zero.

The acceleration of a rocket leaving the earth increases because:
a) its mass is decreasing.
b) air resistance is decreasing.
c) gravitational pull is decreasing.