An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 ms-1 and the second part of mass 2 kg moves with 8 ms-1 speed. If the third part files off with 4 ms-1 speed, then its mass is :

Question

An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 ms-1 and the second part of mass 2 kg moves with 8 ms-1 speed. If the third part files off with 4 ms-1 speed, then its mass is : (A) 17 kg (B) 3 kg (C) 5 kg (D) 7 kg

Tardigrade Admin · Accepted Answer

From conservation of momentum m(4) = √ (1 × 12)2 + (2 × 8)2 ⇒ m = 5 kg

17 kg

3 kg

5 kg

7 kg

From conservation of momentum m(4)=(1×12)2+(2×8)2​⇒m=5kg

From conservation of momentum
$m (4) = (1 \times 12)^{2} + (2 \times 8)^{2} \Rightarrow m = 5 k g$