Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
In science, 'Work' is said to be done only when a force applied to an object causes that object to move over a certain distance.
Two conditions are necessary for work to be done: 1. A force must act on the object. 2. The object must move in the direction of the applied force.
If a force is applied but the object does not move, the work done is considered zero (). For example, pushing against a stationary wall results in no work.
Work is directly proportional to both the force applied () and the distance () moved by the object.
Energy is defined as the ability or capacity to do work. Without energy, we cannot apply the force required to move objects.
The SI unit of work is the Joule ().
📐Formulae
💡Examples
Problem 1:
A boy pushes a toy car with a force of and moves it a distance of . Calculate the work done.
Solution:
Explanation:
Since the toy car moved in the direction of the force, we multiply the force by the distance to find the work done.
Problem 2:
A girl is pushing a heavy cupboard with a force of , but the cupboard does not move at all (). How much work is done?
Solution:
Explanation:
In science, if there is no displacement (the object doesn't move), the work done is always zero, regardless of how much force is applied.
Problem 3:
If Rahul does of work by moving a box , how much force did he apply?
Solution:
Explanation:
By rearranging the work formula, we can find the force by dividing the work done by the distance moved.