Energy is like having fuel in a gas tank—it’s the stored potential to make something happen, like moving a car. Work, on the other hand, is when you actually drive the car using that fuel. So, energy is the possibility to move the car, and work is when you press the gas pedal and the car moves forward, converting the fuel’s potential into actual motion.
Real Life Examples
Some real life examples are listed below:
- Charging your smartphone is energy; using it to make calls is work.
- Winding a toy car’s spring is energy; letting it go and making the car move is work.
- Fuel in a rocket is energy; the rocket lifting off is work.
- Stretching a rubber band is energy; letting it snap and move is work.
- Eating food is energy; using that energy to walk and run is work.
Mathematical Form
- Energy: Energy is a scalar quantity and can exist in various forms. The total energy (E) of a system is the sum of its kinetic energy (KE) and potential energy (PE):
E=KE+PE - Work: Work (W) is calculated as the product of the force (F) applied on an object and the distance (d) over which the force is applied in the direction of the force:
W=F×d
If the force is not constant or is at an angle (θ) to the direction of motion, the equation is modified to:
W=F×d×cos(θ)
Difference Between Work and Energy
| Definition | Work is the transfer of energy through the application of force over a distance. | Energy is the capacity to do work. |
| Formula | W=F×d or W=F×d×cos(θ) | E=KE+PE |
| Units | Joules (J) | Joules (J) |
| Nature | Scalar quantity | Scalar quantity |
| Examples | ||
| a. | Pushing a car along the road. | A moving car has kinetic energy. |
| b. | Stirring a cup of coffee. | Hot coffee has thermal energy. |
| c. | Stretching a rubber band. | Compressed springs have potential energy. |
| d. | Climbing a flight of stairs. | Food you eat provides the energy for your body. |
Crux Line
Work is the transfer of energy to or from an object, involving the application of force over a distance. Energy, on the other hand, is the capacity of an object to do work or cause a change in its surroundings.
