2.2 Newton’s Laws

Question 1

What can a force do?

Answer 1

Forces can change the shape or motion of an object. Forces can only be seen by their effect represented by arrows and measured with Newtons.

Question 2

How do bodies interact to give forces?

Answer 2

When bodies interact they exert forces by directly touching called contact or at a distance called non-contact. A field is where bodies experience force.

Question 3

What is newtons 3rd law?

Answer 3

When 2 bodies interact they exert a force upon each other that is equal in size but opposite in direction. ‘Every action has a reaction’.

Question 4

What is Newton’s first law and inertia?

Answer 4

A body will remain at rest or be at constant velocity unless acted on by a resultant force. Inertia measures the difficulty to change the velocity of a body; greater mass = greater inertia. Therefore when a body is at rest the resultant force is 0.

Question 5

What is Newton’s 2nd law?

Answer 5

When resultant force does not equal 0, The acceleration of a body is directly proportional to the resultant force acting upon it. If you push something harder, it will accelerate quicker. Therefore acceleration is inversely proportional to mass. (F=MA)

Question 6

What is momentum?

Answer 6

Momentum (kgm/s) = Mass (kg) * Velocity (m/s)

Momentum measures how difficult it is to stop a moving object. Momentum in a system is always conserved so total momentum before and after an event is equal.

Question 7

What is work done?

Answer 7

Work done (J) = Force (N) * Displacement (m)

When a force acts on an object and moves it, work is done and this is the transfer of energy (Joules). We assume this is at constant velocity.

Question 8

What is power?

Answer 8

Power (Watts) = Energy (J) /// Time (s)
Power (Watts) = Potential Difference (V) *** Current (I)

Power is the rate of energy transfer. 1 Watt is 1 Joule of energy transferred in 1 second.