Chapter 9 Force Mass Momentum

Define Force

Anything that causes the velocity of an object to change

Force is what causes acceleration

F=ma

Unit: Newtons (N)

What is Mass?

The mass of an object is a measure of its inertia

The mass (m) of a body is a measure of how difficult it is to accelerate that body

What is Weight?

The weight of an object is the force of the Earth’s gravity acting on it

W=mg

What is Momentum?

p=mv

m is mass

v is velocity

unit: kg m^-1

State Newtons 1st Law of Motion

Every body will remain in a state of rest or travelling with a constant velocity unless an unbalanced external force acts on it

State Newtons 2nd Law of Motion

When an unbalanced force acts on a body, the rate of change of momentum is directly proportional to the force and takes place in the direction of the force

State Newtons 3rd Law of Motion

If body A exerts a force on a body B, then body B exerts an equal but opposite force on body A

To Show that F=ma is a special case of Newtons 2nd Law

State the principal of conservation of Momentum

The total momentum of a system remains constant provided no external forces act on the system