Question

A box of weight 100 N is lifted to a height of 10 m above ground. How much potential energy will be stored in the box?
9800 J
1000 J
2000 J
none of the above​

Answer 1

Weight = 100N

Height = 10m

‎

Mass of box = $\frac{Weight}{Acceleration}$

Mass = $\frac{100}{9.8}$

Mass = $\dfrac{\frac{100}{98}}{10}$

Mass = ${{\frac{100}{98}}\times{10}}$

Mass = $\cancel{\dfrac{1000}{98}}$

Mass = $\frac{500}{49}kg$

‎

Now,

P.E. = mgh

where,

m = mass = $\frac{500}{49}\:kg$

g = Acceleration due to gravity = 9.8m/s² = $\frac{98}{10}m/s²$

h = height = 10m

‎

P.E. = $\frac{500}{49}\times{\dfrac{98}{{\cancel{10}}}}\times{\cancel{10}}$

P.E. = $\dfrac{500}{{\cancel{49}}}\times{\cancel{98}}$

P.E. = $500\times{2}$

‎$\underline{P.E.\:=\:1000J}$

‎

‎

Therefore,

Correct option is $\Large\mathrm{\underline{\underline{\red{(ii)\:1000J}}}}$