Work:
Work is calculated as the product of the force and displacement.
Let us consider,
\(F\) → Constant force acting on an object
\(s\) → Displacement of the object in the direction of the force.
\(W\) → Work done.
\(Workdone\ =\ Force\ \times\ Displacement\)
\(W\ =\ F\times s\)
Let us consider, When the object is lifted. the force exerted by you is used to do the work. When the object moves upwards, you exert force in the same line of direction of displacement.
Positive work:
When force and displacement are in the same direction, the work performed on an object is said to be positive work.
Negative work:
Negative work is performed if the displacement is opposite to the direction of the force applied.
Energy:
Life is impossible without energy. The energy demand is ever increasing.
Kinetic energy:
Kinetic energy is the energy contained by an object due to its motion. The kinetic energy of an object increases with its speed.
The kinetic energy of a body moving with a certain velocity is equal to the work done on it to make it obtain that velocity.
A moving object can do work. An object which is moving faster can do more work than the same object moving comparatively slow. A moving bullet, blowing wind, a rotating wheel, a speeding stone can do work. Objects in motion contain energy. We define this energy as kinetic energy.
A coconut is falling from the tree, a speeding car, a rolling stone, a flying aircraft, running water, blowing wind, a running athlete etc., possess kinetic energy.
kinetic energy is the energy contained by an object due to its motion. The kinetic energy of an object increases with its speed.
Potential energy:
Potential energy is energy that is stored or conserved in an object or substance. This stored energy is based on the position, arrangement or state of the object or substance.
You can think of it as the energy that has the 'potential' to do work. The stored energy will be released, when the position, arrangement or state of the object changes.
Potential energy is mainly classified into two types:
- Gravitational potential energy
- Elastic potential energy
Gravitational potential energy is energy in an object that is held in a vertical position.
Elastic potential energy is energy stored in objects that can be stretched or compressed.