# Mechanics

calculus-based physics for scientists and engineers

## An Introduction to Forces

### What is a force?

The essence of a force is not far removed from our everyday usage of the word. If you push, or pull, or hit something, you exert a force on it. Forces require two objects: an agent and an object. The agent exerts the force on the object. Force is a vector. Except for gravity, for every force we will study, the agent must be in physical contact with the object to exert a force on it.

### Finding and Identifying Forces

While the concept of a force is intuitive, clearly identifying them sometimes isn't. Applying what we know about forces from above can help.

### One Force on One Object in One Dimension

The effect of a force may be very different from our natural intuition.

Forces cause changes in velocities.

Forces lead to accelerations. In fact, the acceleration of an object is proportional

to the force. The constant of proportionality is one over the mass of the object.