1. Forces and Motion

Explain the features of cars that decrease momentum?

Crumple zones - Absorb the impact force.

Seat belts and Air bags - Increases the time taken for the passenger to experience the impact force.

State the conservation of mass?

The total momentum before an interaction is equal to the total momentum after an interaction.

State Newton’s third law?

For every force exerted there is an equal and opposite force.

Define centre of gravity?

The point through which the weight of an object acts.

State the principle of moments?

If an object is balanced, the total clockwise moment about a pivot equals the total anticlockwise moment about that pivot.

How does force on a light beam vary with the position of a heavy object placed on the beam?

As mass moves left to right, F1 decreases and F2 increases.

If right hand support removed F2 would be 0 and beam would pivot in clockwise direction.

F2 must supply anticlockwise moment about left hand support to balance moment.