# Simple Machines-Distance vs Force Trade Off

Assuming an equal amount of work, which of these screws would require the least amount of force?

As a machine changes the size of the force the distance through which the force is exerted must also change.

Force or distance can increase but both cannot increase. When one increases the other must decrease.

The formula for work =Force x Distance

If it takes 150 newtons to move an object 1 meter it will require 150 joules of work.

Now let’s use a ramp.

Take the same object and move it 1 meter off the ground but now you are moving it on a ramp a distance of 5 meters Therefore you will only have to use 30 newtons of force

So as distance increases force decreases and as distance decreases force increases

Let’s apply this concept to some simple machines.

When a wedge gets longer the force decreases.

As the distance from the fulcrum of a lever increases the force will decrease.

When there are more pulleys it takes less force.

When the radius of a wheel gets longer it requires less force.

When the rivets on a screw get closer together it requires less force.

So remember as distance increases force decreases and as distance decreases force increases.

So the answer to our first question is B because the rivets are closer together.