An explosion blows a rock into three parts. Two parts go off at right angles to each other. …

Q: An explosion blows a rock into three parts. Two parts go off at right angles to each other. These two are, 1 kg first part moving with a velocity of 12 m/s and 2 kg second part moving with a velocity of 8 m/s. If the third part flies off with a velocity of 4 m/s, its mass would be

(a) 5 kg

(b) 7 kg

(c) 17 kg

(d) 3 kg

Ans: (a)