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# MOTION: FORCE AND FRICTION

CONTENT

Force

1. Definition of Force
2. Types of Forces

Friction

1. Definition of Friction
2. Types of Friction
3. The Laws of Solid Friction
4. Coefficient of friction
6. Methods of Reducing Friction

## Force

### Definition of Force

Force can be defined as that which changes or tends to change the state of rest or uniform motion of a body. Force is a vector quantity and the S.I. unit is Newton.

Force can cause a body at rest to move, it causes a moving object to accelerate, change direction, move in a curved path etc.

### Types of Forces

There are two types of forces, namely contact force and force field. Contact force is a force that exists between bodies by virtue of their contact. They are push, pull, normal reaction, tension in strings, wires or frictional force.

Force field/non-contact force is the force that exists within a vector field such as gravitational field, magnetic field, electric field, and nuclear field.

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