Forces and elasticity and moments levers and gears

elastically deformed

If an object goes back to its original shape after the force has been removed it has been elastically deformed

Inelastically deformed

If an object does not go back to its original shape after the force has been removed

Hookes law

States that the extension of elastic object is directly proportional to the force applied

Force equation ( hookes law)

Force = spring constant x extension

elastic potential energy equation

0.5 x spring constant x extension squared

The turning effect of a force (the moment) depends on three things

• Size

• Distance

• Angle

How to increase the moment

• Use a large force

• Pull on the long end of the spanner ( far from the pivot point)

• Pulling at 90°

Moment of a force equation

Moment = force x perpendicular distance from the pivot

Principle of moments

Sum of clockwise movements = sum of anti-clockwise movements

What are levers

A simple way of achieving mechanical advantage

The greater the length of the lever from the pivot to the applied force the easier it would be to lift the mass.

Each time you pass power from one gear wheel to another you can do one of three things

• Increase speed

• Increase force

• Change direction