Question

A block weighing 20 N is lifted 6 m vertically upward. Calculate the potential energy stored in it.
1) 3.33 J
2) 124 J
3) 72 J
4) 120 J​

Answer 1

$\Large\bf{\color{indigo}GiVeN,}$

Weight of a block is 20N.

The block is lifted 6m vertically upward.

$\Large\bf{\color{cyan}To\:FiNd,}$

The potential energy stored in the block.

$\Large\bf{\color{coral}CaLcUlAtIoN,}$

Weight Of A Body ;-

The force exerted on a body by gravity, is known as Weight of a body.

☆ The expression of weight of a body is

$\orange\bigstar\:\:\bf{\color{olive}Weight\:(W)\:=\:mg\:}--(1)$

$\bf\pink{Where,}$

m = mass of a body

g = gravitational acceleration

$\bf\red{We\:know\:that,}$

$\green\bigstar\:\:\bf\blue{Potential\:Energy\:=\:mgh\:}$

$\bf\pink{Where,}$

h = Height

➡ From equation(1) using the expression of weight in the above equation

$:\implies\:\:\bf{Potential\:Energy\:=\:Weight\times{Height}\:}$

$:\implies\:\:\bf{Potential\:Energy\:=\:20\:N\times{6\:m}\:}$

$:\implies\:\:\bf{Potential\:Energy\:=\:120\:N.m\:}$

$:\implies\:\:\bf\purple{Potential\:Energy\:=\:120\:J\:}$

$\Large\bold\therefore$ The potential energy stored in the block is 120 J.

$\red\bigstar\:\:{\boxed{\boxed{\green{\bf{Correct\:Option\:\longrightarrow\:(4)\:120\:J\:}}}}}$