# How to Calculate Force

When a force acts on an object, the object accelerates. Examples of forces in nature are gravity, friction, electricity, and magnetism.

### Instructions

- Step 1: Recognize that the work you do to move an object is equal to the force you exert on it times the distance it moves. You can rearrange this relationship to calculate the force on the object by dividing the amount of work you perform by the distance the object moves. Now you can take a well-earned breather.
- FACT: Physicists have identified 4 fundamental forces. They are the strong force, electromagnetic force, weak force, and gravitational force.
- TIP: The force on an object at the Earth's surface due to gravity is equal to the mass of the object times the Earth's mass times the universal gravitational constant divided by the square of the Earth's radius.
- Step 2: Compute gravitational attraction using the fact that every particle in the universe is attracted to every other particle with a force equal to the products of their masses times the universal gravitational constant divided by the square of the distance between them.
- Step 3: Consider an object in circular motion. The object accelerates toward the center of the circle by an amount equal to the square of its velocity divided by the radius of the circle. Multiply this acceleration by the mass of the object to calculate the centripetal force acting on the object.
- Step 4: Know that, according to the laws of physics, the force needed to accelerate an object of a given mass is equal to the mass of the object times the acceleration