Effort and load

The idea

The force applied to a machine is the effort and the force to be overcome is the load; mechanical advantage = load / effort.

Helping hand

With a machine you push or pull with some force, and the machine moves a load that needs a different force.

If the load is bigger than the force you apply, do you think the machine is helping?

• Yes, it helps by magnifying the force
• No, it must be giving less
• It makes no difference

Compare the forces

Set the load and the effort. Watch the ratio.

A ratio of forces

When the load was 200 N and the effort 100 N, the load was twice the effort, and the ratio was 2. We call this ratio the mechanical advantage. It tells how much the machine changes the magnitude of the applied force.

The force we apply to a machine is the effort; the force to be overcome is the load. Mechanical advantage = load / effort.

Notes

Effort = the force we apply; load = the force to be overcome; mechanical advantage = load / effort.

Check yourself

What is the effort?

A machine overcomes a load of 120 N with an effort of 40 N (an example). What is its mechanical advantage?

Answer: 3

120 N ÷ 40 N = 3.

The effort and the load are equal in magnitude. The mechanical advantage is…

A machine has a mechanical advantage greater than 1. Compared with the load, the effort is…

• The force we apply to the machine — correct. Yes!
• The force that has to be overcome. That is the load. The effort is the force we apply.
• The work done by the machine. The effort is a force, the one we apply to the machine.
• 0. Load divided by effort is 1 when they are equal, not 0.
• 1 — correct. Yes!
• 2. Equal forces give a ratio of 1.
• larger. Load / effort greater than 1 means the load is larger than the effort.
• equal. Equal forces give a mechanical advantage of 1.
• smaller — correct. Yes!