Momentum and Moments

What is momentum?

A property linked to the motion of an object. It depends on its mass and velocity and is measured in kgm/s.

What is the new equation for Newton’s Second Law when combined with force = mass x acceleration?

force = change in momentum/ time

What does the law of conservation of momentum state?

‘the total momentum before a collision is equal to the total momentum after a collision, if there is no external force acting on the objects.

Name the 3 points when using these equations

v = u + at

x = ut + ½ at²

x = u+v/ 2 x t

v² = u² + 2ax

1. Check the units (e.g. make sure the distance is in meters not km.

2. If the object is stationary, at rest or stopped, its velocity is 0m/s. This could be the initial or final velocity.

3. Work out what information is in the question, then choose and write out the equation before you put any numbers in or rearrange it.

What is a moment?

A turning force

What equation can we use to calculate moments?

Moment = force × distance

What does the principle of moments state?

When an object is balanced, the sum of the clockwise moments is equal to the sum of the anticlockwise moments.