momentum, Impulse and collision

 Concept map of Momentum and Impulse

Momentum

The Momentum is a body is equal to its mass multiplied by its velocity.

Momentum is measured in N s.

Note that momentum is a vector quantity , because the velocity is a vector quantity , while mass is a scalar quantity , in other words the direction is important.

Conservation of Momentum

When there is a collision between two objects, Newton's Third Law states that the force on one of the bodies is equal and opposite of the force on the other body.

Therefore, if no other forces act on the bodies (in the direction of collision) , then the total momentum of the two bodies will be unchanged. Hence the total momentum before collision in a particular direction = total momentum after in a particular direction.

This can be used to solve problems involving colliding spheres (see also: restitution).

The formula of Momentum

   p = m . v       Where :  m = mass (kg)

                                       p = momentum (kg m/s)

                                       v = velocity of body (m/s)

Application of momentum

Impulse

The impulse of a force (also measured in N s) is equal to the change in momentum of a body which a force causes.

This is also equal to the magnitude of the force multiplied by the length of time the force is applied.

The Formula of Impulse 
Impulse = change in momentum = force × time

 The Application of Impulse

The Application of Collision