# What is Power Class 9

Last updated on May 6th, 2023 at 06:18 am

In this post, we will define Power (in physics), and list down different formulas of power for class 9. We will also solve a sample numerical using the power formula and concept.

## What is Power Class 9 – Physics

Power is the rate at which work is done or the rate at which energy is supplied or used. Like work and energy, power is also a scalar quantity.

The SI unit for power is Joules per second (Js-1), which is defined to be a Watt (W).

So 1 W = 1 J/s. There are other popular units like Kilowatt and horsepower. 1 kilowatt = 1000 Watt and 1 Horsepower = 746 Watt.

### Power formula class 9

When we define power as the rate of work done or rate of energy supplied (or used) we get the following formulas:

Average Power formula

Average Power = Work done during some time interval / Duration of time interval ……………… (1)

Average Power = Total Energy supplied or used during some time interval / Duration of time interval ………… (2)

Instantaneous Power formula

The rate at which work is done might not be constant. We define instantaneous power P as the quotient in Eq. (1) as Δt approaches zero: