Module 1: Newton's laws and momentum

Question 1

Newton’s first law

Answer 1

An object will remain at rest or keep travelling at constant velocity unless it is acted on by an external force.

Question 2

Newton’s second law

Answer 2

The net force acting on an object is equal to the rate of change of its momentum. The net force and the change in momentum are in the same direction.

Question 3

Newton’s third law

Answer 3

When two bodies interact the forces they exert on each other are equal and opposite.

Question 4

Linear momentum

Answer 4

Linear momentum is the product of an object’s mass and its velocity. (P=mV)

Question 5

Net force on a body

Answer 5

Net force on a body is equal to the rate of change of its momentum.

Question 6

Impulse

Answer 6

Impulse is the product of the force ‘F’ and the time ‘Δt’ for which it acts.

Question 7

The principal of conservation of momentum

Answer 7

In a closed system, when bodies interact, the total momentum in any specified direction remains constant.

Question 8

Perfectly elastic collision

Answer 8

A collision is perfectly elastic when kinetic energy is conserved. Momentum and total energy are always conserved.

Question 9

Inelastic collision

Answer 9

A collision is inelastic when the kinetic energy is not conserved- some is transferred to other forms such as heat. Momentum and total energy are always conserved.