Question

Four men lift a 400 kg box to a height of 2m and hold it without raising or

lowering it. How much work is done by the men in lifting the box?

( Assume g= 2 10ms− )
​

Answer 1

Answer:

This is a potential energy {P.E.}

P.E.= mgh

where m= mass of object =400 kg

g= acceleration due to gravity = 10 ms^-2

h= height between object and surface=2 m

put all the value in formula, we get

P.E. = 400× 10 × 2 = 8000 J

Answer 2

$\LARGE\bold{\underline{quєstíσn\: :}}$

$\implies$ Four men lifting a 400 kg box to a height of 2m and holding it without raising or lowering it . How much work is done by the men in lifting the box ?

$\:\:$

$\LARGE\bold{\underline{αnswєr\: :}}$

$\Large\bf{\sf{\mathtt{\color{maroon}{ցíѵҽղ:-}}}}$

⟼ Four men lifting a box of 400 kg at a height of 2m by holding it.

⟼ The acceleration due to gravity is $\bf{10ms}^{-2}$

$\:$

$\Large\bf{\sf{\mathtt{\color{maroon}{Եօ \: ƒíղժ}}}}$

⟼ The work done by them .

$\:$

$\Large\bf{\sf{\mathtt{\color{maroon}{աҽ\: Ƙղօա\: ԵհɑԵ}}}}$

⟼ $\bold\gray\dag{\large{\underline{\boxed{\textbf{\textsf{P.E.=mgh}}}}}}\bold\gray\dag$

Where ,

• P.E. = Potential energy

• m (mass of the object) = 400 kg

• g (acceleration due to gravity) = $\bf{10ms}^{-2}$

• h (height b/w the object and the surface) = 2m

$\:$

$\Large\bf{\sf{\mathtt{\color{teal}{ՏօӀմԵíօղ}}}}$

⟼ Substituting the values as follows :

$\implies\sf{P.E.=mgh}$

$\implies\sf P.E. = {400}\times{10}\times2$

$\sf\implies P.E.= 8000 j (joule) ans.$

$\:$

Therefore ,

The work done by the men is 8000 j

$\:$