Two forces can be added together to find a resultant force. In the diagram of a toy trailer below, when two children pull on the handle, one with a force of 3 newtons (N) to the left and one with ...

Friction is a force that opposes motion. It is present whenever two surfaces rub over each other, such as when you rub your hands together, or when you apply the brakes on a bike or in a car.

With their whip-like tails, human sperm propel themselves through viscous fluids, seemingly in defiance of Newton's third law ...