Question

A big particle of mass (3 + m) kg blasts into 3 pieces, such that a particle of mass 1 kg moves along x-axis, with velocity 2 m/s and a particle of mass 2 kg moves with velocity 1 m/s perpendicular to direction of 1 kg particle. If the third particle moves with velocity $\sqrt{2}$ m/s, then m is :

• A. 2 kg
• B. 1 kg
• C. 2$\sqrt{2}$kg
• D. None of these

Answer 1

Answer: (A)

2 kg

Answer 2

Conservation of linear momentum

0 = (1 × 2$\widehat{i}$) + (2 ×

1$\widehat{j}$) + m$\overrightarrow{v}$

Ž m$\overrightarrow{v}$ = – 2$\widehat{i}$ – 2$\widehat{j}$Ž mv = 2$\sqrt{2}$

Ž m($\sqrt{2}$) = 2$\sqrt{2}$Ž m = 2 kg