WHAT FORCES DO

  A force can make an object move

  A force can make a moving object stop

  A force can change the speed of a moving  object

  A force can change the direction of a moving object

  A force can change  the shape of on object

  THE  S.I UNIT OF FORCE

      The SI unit for force measurement is newton (N).

      A newton is a force that will cause a 1 kg mass to change its speed by 1 m/s every second of the force applied.

      Force is equal to mass times acceleration.

                             F = ma

TYPES OF FORCE

      There are two types of forces : Contact force and non-contact forces.

      A contact force occurs when the force touches the object or material on which the force acts

      A non-contact force accurs when the objects or materials do not touch each other.

      Strain Force

      when some materials are squashed, stretched, twisted or bent they exert a force which acts in the opposite direction to the force acting on them. These materials are called elastic materials

      Muscular force

      Spring force

      Frictional force

      Machine force

NON-CONTACT FORCE

      Magnetic Force

                A magnet has  a north seeking pole and a south-seeking pole. If you pick up two magnet and bring either their north poles or south poles together you will feel a force  pushing your hands apart as similar poles repel each other.

      Electrostatic Force

                There are two kinds of charge : positive charge and negative charge. The forces between the charges can be investigated by suspending a plastic rod so that it can swing freely, giving the rod an electrostatic charge and then bringing rods with different charges close to it.

      Gravitational Force

                There is a force between any two masses in the inverse. The masses may be small such as those of an ant and a pebble or they may be very large such as those of the sun and the Earth.

Resultant Force

Two or more force working on the same                                direction and work line have resultant force of                  the sum of all force