Introduction to Force

Types of Forces

There are various types of forces, such as gravitational force, frictional force, tension force, electrostatic force, etc.
Gravitational force is the force of attraction between all masses. It is the weight of an object, not its mass, that demonstrates the effect of gravity.
Frictional force opposes the motion of an object and always acts in the opposite direction to the way an object wants to slide. If an object is sliding to the right, friction is sliding to the left.
Tension force is the force that is transmitted through a string, rope, or wire when it is pulled tight by forces acting from ends.
Electrostatic force: Two charged objects will either attract or repel each other.

When the forces acting on an object are balanced, the object stays still or continues moving at the same speed and in the same direction.
When the forces acting on an object are unbalanced, the object accelerates in the direction of the unbalanced forces. It can change the object’s speed, direction, or both.

Newton’s First Law (Law of Inertia) states that an object at rest tends to stay at rest, and an object in motion tends to stay in motion, unless acted upon by an unbalanced external force.
Newton’s Second Law states that force is equal to the mass of the object times its acceleration (F = ma). So, acceleration of an object depends on the magnitude of the force applied and inversely depends on the mass of the object.
Newton’s Third Law states that for every action there is an equal and opposite reaction.

Work done is the measure of energy transfer when a force moves an object. It is calculated using the formula: Work done = Force x Distance. It is measured in joules (J).
More work is done and more energy is transferred when a greater force is applied or the object moves a greater distance.