Class 11 NEET Physics Work, Energy and Power Questions

When an explosion breaks a rock, by the law of conservation of momentum, initial momentum is zero and for the three pieces,
Total momentum f the two pieces 1 kg an 2 kg
=√122+162=20kgms−1
The third piece has the same momentum and in the direction opposite to the resultant of these two momenta.
∴ Momentum of third piece =20kgms−1
Velocity =4m−1
∴ Mass of the 3rd piece =

mv

V

=

20

4

=5kg