Question

A large box is taken to a height of 8 m, with energy spent is 64,000 J. The mass of the box is
(Take g = 10 ms^-2)

• A. 400 kg
• B. 800 kg
• C. 700 kg
• D. 1600 kg

Answer 1

The correct option is B

800 kg

Step 1: Given data:

Height to which the box is taken, h = 8 m,

Energy spent, E = 64000 J,

Acceleration due to gravity, g = 10 ms^-2, and

To find, Mass of the box, m

Step 2: Formula used

1. Potential energy is the energy possessed by the body due to its position.
2. The energy required to take the box from reference level to height h = Potential energy at height h.
   Energy required = m x g x h
   $\mathrm{m}=\frac{\mathrm{E}}{\mathrm{g}\mathrm{x}\mathrm{h}}$

Substituting the known values,

$\mathrm{m}=\frac{64000\mathrm{J}}{(10{\mathrm{ms}}^{-2})\mathrm{x}(8\mathrm{m})}$

m = 800 kg

Step 3: Final answer

Thus, the mass of the box is 800 kg.

Hence, option (B) is correct.