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 m/s and the second part of mass 2 kg moves with second part of mass 2 kg moves with 8 m/s speed. If the third part flies off with 4 m/s speed, then its mass is,
-
3 kg
-
5 kg
-
7 kg
-
17 kg
Solution
B.
5 kg
We have,
p1 + p2 + p3 = 0 [ because p = mv]
Therefore,
1 x 12 i + 2 x 8 j + p3 = 0
Now. p3 = m3 v3
This implies,
