Tag: idea of energy

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Questions Related to idea of energy

Multiple choice physics energy and its forms idea of energy introduction to work and energy work and energy

The force acting on a 4gm mass in the energy region ${ U=8x }^{ 2 }$ at x= -2 cm is :

  1. 8 dyne

  2. 4 dyne

  3. 16 dyne

  4. 32 dyne
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Given,

$m=4gm$
$U=8x^2$

The force acting on mass $m$ in the potential energy $U$  at $x=-2cm$ will be

$F=-\dfrac{dU}{dx}$
$F=-\dfrac{d(8x^2)}{dx}$
$F=-16x$
$|F| _{x=-2cm}=-16\times(-2)=32dyne$
The correct option is D.



Multiple choice physics energy and its forms idea of energy introduction to work and energy work and energy

Name the quantity which is measured in $Wh$.

  1. Force

  2. Power

  3. Energy

  4. All the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

We know that $ power = work/ time$.

Power has unit $W$ and time can have either seconds or minutes or hours.Hence work can have either $W\ min$ or $Wh$ or $Ws$. We in general consider work is nothing but energy. Hence energy can have unit $Wh$.