Question

Question 73

The mass of an aluminium rod varies directly with its length. If a 16 cm long rod has a mass of 192 g, find the length of the rod whose mass is 105 g.

Answer 1

According to the question, the mass (m) of an aluminium rod varies directly with its length (l). Here, we use the direct proportion.
So,
$\frac{m}{l}=k\left(constant\right)\therefore \frac{m}{l}=\frac{192}{16}=12\Rightarrow k=12$

If mass of the rod = 105 g

Then,
$\frac{m}{l}=k\Rightarrow \frac{105}{l}=12\Rightarrow l=\frac{105}{12}=8.75cm$