Question

A bomb of mass 1 kg is thrown vertically upwards with a speed of 100 m/s. After 5 seconds it explodes into two fragments. One fragment of mass 400 gm is found to go down with a speed of 25 m/s. What will happen to the second fragment just after the explosion? (g = 10 m/s²)
(a) It will go upward with speed 40 m/s
(b) It will go upward with speed 100 m/s
(c) It will go upward with speed 60 m/s
(d) It will also go downward with speed 40m/s

Answer 1

(d) it will go upward with the speed 60 m/s

Answer 2

Answer:

(B) It will go upward with speed 100 m/s

Explanation:

Initial velocity u = 100 m/s (Given)

Time taken t = 5 sec (Given)

Let the mass of bomb when it goes upwards be = m

Equation of motion - v = u - gt

v = 100 - 10 × 5

v = 50 m/sec

Thus, the final velocity of bomb will be 50 m/s

One fragment of 400 gm will fall with a velocity of 25 m/s,

=  (1)(+50)=(0.4)(-25)+(0.6)v2

= 100

Therefore, another fragment of 400 gm will move upwards with the velocity of 100 m/s