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 flies off with 4 $ms^{-1}$ speed, then its mass is

• A. 3 kg
• B. 5 kg
• C. 7 kg
• D. 17 kg

Answer 1

Answer: (B)

5 kg

Answer 2

The correct option is (B): 5 kg