Find the volume (in cm³) of a piece of metal of density 5000 kg/m³ and which weighs 10.8 N. (Use g = 10m/s²)

Question

Question

This question was previously asked in

RRB ALP Fitter 21 Jan 2019 Official Paper (Shift 2)

Answer 1

Concept:

Weight:

It is the gravitational force which attracts the body towards the centre of earth.
It's unit is Newton (N).

\(W=mg\)

Where, W = weight of the body, m = mass of the body, g = acceleration due to gravity.

Density:

\(\rho=\frac{m}{v}\)

Where, \(\rho\) = density, m = mass, v = volume

Calculation:

Given:

density of metal, ρ = 5000 kg/m³

weight, W = 10.8 N

g = 10 m/s²

Now, Weight (W) = mg

where, m is the mass of metal

\(m=\frac{W}{g}=\frac{10.8}{10}\) = 1.08 kg

Then, \(ρ = \frac{mass}{volume}\)

\(volume=\frac{m}{ρ}=\frac{1.08}{5000}\)

volume (v) = 0.000216 m³ = 216 cm³

Thus, option (1) is correct answer.

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