AQA AS mechanics key words

Question 1

Projectile

Answer 1

Travels in a parabola through the air with no horizontal driving force. Vertical motion is independent of horizontal motion. Acceleration is vertically downwards.

Question 2

Newton’s 1st Law

Answer 2

Until acted on by a resultant force, objects at rest stay at rest and objects moving at constant velocity will stay moving at that velocity. This is called inertia

Question 3

Newton’s 2nd Law

Answer 3

Acceleration is proportional to the resultant force. The larger the resultant force the more the object accelerates.

Question 4

Terminal velocity

Answer 4

Maximum, constant velocity. Air resistance and weight balance.

Question 5

Newton’s 3rd Law

Answer 5

When two objects interact, the forces they exert on each other are equal and opposite. Action and reaction are equal and opposite

Question 6

Conservation of momentum

Answer 6

Total momentum before = total momentum after.

Question 7

Elastic collision

Answer 7

A collision in which no momentum or kinetic energy is lost.

Question 8

Inelastic collision

Answer 8

A collision in which momentum is conserved but kinetic energy is not.

Question 9

Principle of
moments

Answer 9

sum of clockwise moment s = sum of anticlockwise moment s (about any given point) (for a system in) equilibrium.

Question 10

Centre of gravity

Answer 10

The point at which we consider the mass of an object being concentrated.