Question

A bomb of mass 3 kg at rest explodes in air into two pieces of masses 2kg and 1kg. the smaller mass goes at a speed of 80m/s. the total energy imparted to the two fragments is

Answer 1

Answer:

Explanation:

Given A bomb of mass 3 kg at rest explodes in air into two pieces of masses 2kg and 1kg. the smaller mass goes at a speed of 80m/s. the total energy imparted to the two fragments is

Given m1 = 2 kg, m2 = 1 kg, v2 = 80 m / s

We know that m1v1 + m2v2 = 0

So m1v1 = - m2v2

So v1 = -m2v2 / m1

       = - 1 x 80 / 2

   So v1 = - 40 m / s

Now total energy = 1/2  m1v1^2 + 1/2 m2 v2^2

                             = 1/2 x 2 x – 40^2 + 1/2 x 1 x 80^2

                             = 1600 + 3200

                            = 4800 J

                           = 4.8 K J

Answer 2

Answer:

for all those wondering why m1vi+m2v2=0

Explanation:

mv=0, beacause mass is at rest