Forces in action

Define the Newton

Force required to accelerate 1kg at 1ms^-1

Define weight

Acceleration caused by gravity (w=mg)

Define the centre of mass

The point through which any externally applied force creates straight line motion and no rotation

What is the centre of weight

The point where the entire weight of an object acts and around which the object will balance

What should be used to find the centre of mass of an object

A plumb line

Define drag

Friction in fluid, acts in the opposite direction to motion

What two factors affect the magnitude of drag

Velocity and surface area

Define a moment

A measure of the turning effect of force around a point

What is the equation for a moment

Force x perpendicular distance

What is the principle of moments

The clockwise moments must be equal to the anti-clockwise moments

What is the torque

The moment caused by a couple

What are the two conditions for equilibrium

Sum of forces must equal 0 and sum of the Moments must equal 0

What is the equation for density

Mass / volume

What should be used to find density of an irregular solid

Displacement can

What is the equation for pressure

Force / Area

Want causes atmospheric pressure

Caused by gravitational attraction of particles towards the surface of the earth

What is the equation for pressure

ρ x g x h

What is archimedes principle

The upthrust is equal to the weight of fluid displaced