# Q & A: Is there a most effective force?

Q:
Our Science teacher asked me and some other students to research for answers to my other classmates' questions about forces. I was assigned to the question "What is the most effective force?" I can't find an answer on the internet. I don't even know if that question makes sense. Can you answer that question?
- Beatrice (age 11)
Philippines
A:

I agree, that question doesn't really make sense. It could mean several different things. Maybe your teacher would be satisfied if you explain why it's a confusing question.

If "effective" means "strong," there is no force that is always stronger than other forces. Usually the strength of a force depends on something like how hard you push, or how large an electric current is, or how close together two objects are. Different kinds of forces are stronger in different situations.

Maybe "effective" means "efficient." There are different ways to apply force which could make a job easier or harder. For example, if you want to push a box across the floor, you should apply your force straight forward, not down towards the floor. The best way to apply force is different in different situations.

Rebecca H.

PS: This gets even more confusing because physicists sometimes mean something else when they use the words "strong" or "weak" to describe forces. There are four known fundamental forces: gravity, electromagnetism, the strong nuclear force, and the weak nuclear force. By comparing forces between elementary particles at certain distances to standard physical constants, scientists rank them from "weak" to "strong": gravity is the weakest force, then the weak nuclear force, then the electromagnetic force, and the strong nuclear force is (surprise) the strongest. But this is totally different than whether gravity happens to be a stronger force in a certain situation.

(published on 02/24/2016)