Question

a 40 kg shell is flying at speed of 72km/hr.It explodes into 2 pieces one piece of mass 15kg just slops. what is the speed of other ?

Answer 1

Hello friend

As momentum is always conserved
total initial momentum = total final momentum
Mathematically,
m1u1 + m2u2 = m1v1 + m2v2

Here m=40kg
and u= 72km/hr=20m/s

m1=15kg
v1=0
m2=40-15=25kg
we need to find v2

So
40×20 = 15×0+25×v2
800=25v2
v2=32

So the speed of the other will be 32m/s

HOPE IT HELPS.... :-)

Answer 2

First find the speed of one kg
72/40=1.8 is the speed of one kg.
Now the speed of 15 kg=1.8×15=27km/h

The speed of other=40-15=25
=25×1.8=45km/h.

Hope its helpful