Question

A bomb of mass m= 1 kg thrown vertically upwards
with a speed u = 100 m/s explodes into two parts
after t = 5s. A fragment of mass m2 = 400 g moves
downwards with a speed V, = 25 m/s, then speed
V2 and direction of another mass m, will be :-
(1) 40 m/s downwards (2) 40 m/s upwards
(3) 60 m/s upwards (4) 100 m/s upwards
​

Answer 1

Answer:

v1 is equal to 100 metres per second

Answer 2

Answer:

Required speed is 100 m/s

Explanation:

Velocity of bomb at t= 5 s

We know,

$v = u + at$

Where u is initial velocity and v is final velocity and t is time.

Here given u= 100 m/sec and t = 5 s

Now we are using momentum conversation,

Initial M=Final M

$Initial \: M=Final \: M$

Upward direction (+ve)

$1 \times 50 = - 0.4 \times 25 + 0.6v$

$50 + 10 = 0.6v$

$v = 100 \: m {s}^{ - 1}$

Required speed is 100 m/s