Question

A body of mass 1 kg moving in the x-direction, suddenly explodes into two fragments of mass $\frac{1}{8}kgand\frac{7}{8}kg$ An instant later, the smaller fragment is 0.14 m above the x-axis. The position of the heavier fragment is:

• A. $\frac{1}{50}$ m above x-axis
• B. $\frac{1}{50}$ m below x-axis
• C. $\frac{7}{50}$ m below x-axis
• D. $\frac{7}{50}$ m above x-axis

Answer 1

The correct option is B $\frac{1}{50}$ m below x-axis

Position of COM remains unchanged (all forces are internal).
Initially x coordinate of COM = 0;
i.e.
$0=0.14\times \frac{1}{8}+x\times \frac{7}{8}$
i.e. $x=-\frac{1}{50}m$
Hence the second fragment would be found at $\frac{1}{50}m$ below the x axis.