Forces
Interactions between two objects
What can forces change
Motion of objects
What can forces cause
Acceleration
What can pairs of forces cause
Deformation
Unit for forces
Newtons
Propulsion
For an object to move it must force something to move in the opposite direction
Newton’s 3rd law
Mass
Measures the amount of stuff in an object
Measured in kg
It’s constant
Centre of mass
The point at which mass can be thought to be concentrated
Weight
Force on an object due to gravity
What is weight measured in
Newtons
2 factors the affect gravitational field strength on the surface of a planet is :
1) The mass of the planet
2) the radius of the planet
Resultant force
A single force that can replace a number of forces acting on an object
Newton’s 1st Law
An object will remain at rest or will continue to move with constant velocity unless acted on by another force
The object is in equilibrium
Newton’s 2nd Law
Force = mass*acceleration
Acceleration is directly proportional to the resultant force
Newton’s 3rd law
When two objects interact,
the forces they exert on each other
are equal and opposite
Required practical 7 - Newton’s 2nd Law
PRACTICE ON REVISION CARD
Free Body Diagrams
PRACTICE
Terminal velocity
What happens when a force acts on a stationary object
What is the size of the frictional force
Starts moving in the direction of the force
Size of frictional force initially is 0
Object accelerates so velocity increases
REQUIRED PRACTICAL 6 : STRETCHING A SPRING
REVISION CARD
Inertia
Resistance to change
