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# Power - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

## Quick Facts

• Power is considered one of the most asked concept.

• 18 Questions around this concept.

## Solve by difficulty

A body of mass m  accelerates uniformly from rest to V  in time T  The instantaneous power delivered to the body as a function of time is given by :

A body of mass accelerates uniformly from rest   to $v_{1}$  in time $t_{1}$  The instantaneous power delivered to the body as a function of time t is :

A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to:

## Concepts Covered - 1

Power
1. Definition-

Power is defined as the rate at which work is done or energy is transferred.

1. Dimension -

$ML^{2}T^{-3}$

1. Units-

• SI- Watt or Joule/sec

• CGS- Erg/sec

1. Average power-

$P_{av}= \frac{\Delta w}{\Delta t}= \frac{\int_{0}^{t}p\cdot dt}{\int_{0}^{t}dt}$

1. Instantaneous power-

$P=\frac{dw}{dt}= P= \vec{F}\cdot \vec{v}$

Where, $\vec{F}\rightarrow force$

$\vec{v}\rightarrow velocity$

i.e. power is equal to the scalar product of force with velocity

1. Power expressed as the rate of change of kinetic Energy

$P= \frac{dk}{dt}$

Where, $dk \rightarrow change\: in\: kinetic\: energy$

$dt \rightarrow interval\: of \: time\:$

## Study it with Videos

Power

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