[Newton’s Laws of Motion]

Question 1

1. Newton’s First Law

Answer 1

A body will remain at rest or continue to move with constant velocity unless acted upon by a force.

Question 2

2. Newton’s Second Law

Answer 2

The resultant force acting on an object is directly proportional to the rate of change of momentum and occurs in the same direction of that force. In SI units, net force = rate of change of momentum. Note. F = ma is a ‘special case’ of Newton’s Second Law of Motion where mass is assumed to be constant. F α dp / dt -> F = dp / dt.

Question 3

3. Newton’s Third Law

Answer 3

If object A exerts a force on object B, then object B exerts an equal (in size) but opposite (in direction) force on object A. Requires: two objects, equal forces, opposite direction, same type of force so exist together.

Question 4

4. Linear Momentum

Answer 4

p. Linear momentum = mass x velocity. A property of an object moving in a straight line. Momentum is a vector. Measured in kg ms-1 or Ns. p = m v.

Question 5

5. Vector

Answer 5

A physical quantity that is fully defined by magnitude (size) and direction. For example, velocity, force, acceleration, etc. Momentum is a vector and often stated with a ±.

Question 6

6. Rate of Change

Answer 6

Used to mathematically describe the change in a value over a defined period of time.

Question 7

7. Impulse of a Force

Answer 7

I. The product of force and the time for which the force acts on an object. Area under a force–time graph. Measured in Ns or kg ms-1. I = F Δt = Δ p = mv – mu.