Forces are pushes or pulls that cannot be seen but can be detected through their effects such as making stationary objects move, changing the speed or direction of moving objects, slowing or stopping moving objects, and changing the shape of objects. There are different types of forces including gravitational, elastic spring, frictional, and magnetic forces. Gravitational force is the force of attraction between objects with mass. Elastic spring force stores energy when compressed or stretched and releases it to return the spring to its original shape. Frictional force slows and stops moving objects when they contact another surface. Magnetic force can be either attractive or repulsive depending on the object and magnet.

1. Forces