Suppose you are sitting in a room doing your homework.
Your brother comes and asks you that what are you doing.
You tell him that you are doing some work.
He laughs at you saying that this is not work.
He tells you that scientifically work has a different definition.
Work is defined as the product of force and displacement caused by force.
That means, work is only done when an applied force moves an object by some distance.
When you push an object and it moves from one place to another, work is done by you.
But if you push the object and it doesn’t move then no work is done by you.
If the object doesn’t move ,work done is zero.
The work done in this activity is zero.
Similarly the work done here is also zero.
Let’s calculate the amount of work done in any activity.
Suppose you applied a force F on some object.
This force “F” moved the object by distance “D”.
Then the net work done on the object will be given by W = F x D.
There are three types of work.
Positive Work, Negative Work and Zero Work.
Positive work is said to be done, when the displacement is in the same direction as of applied force.
Here the force and motion of object are in same direction, So, work done is positive.
When the force and displacement are in opposite direction, work is negative.
While drawing water from a well the force of gravity is downward but the bucket moves upward, so work done by gravity becomes negative.
When the body doesn’t move even after applying force or the force is perpendicular to motion.
When there is no motion even after applying force, work is zero.
When the force is perpendicular to motion the work done is zero.
Time for a quick Recap
When a force moves an object through some distance, work is said to be done.
Work is of three types: Positive, Negative and Zero.
When the force and displacement are in same direction, work is positive and When they are in opposite directions work is negative.
When the body doesn’t move even after applying force or the force is perpendicular to motion. Work done is zero.
Keep Working.. :)