Question

A body of mass 50kg is projected vertically upwards with velocity of 100 m/s. After 5s this body
breaks into 20 kg and 30 kg. If the 20 kg piece travels upwards with 150 m/s, then the velocity of
other body will be
​

Answer 1

Explanation:

may be its velocity will be 50 m/s

Answer 2

ANSWER:

The velocity (VB) of the 30 kilogram piece is 15 m/sec downward

EXPLANATION:

The mass of the body that is being projectile upwards = 50 kilograms  

The velocity with which the body of 50 kilogram is projected vertically = 100 m/sec  

It stays up here for 5 seconds, after which it breaks into two parts, one of 20 kilograms and other of 30 kilograms.  

The velocity with which the 20 kilogram peace travels = 150 m/sec  

The velocity of the object just about to break  

$V_{C}=100-9.8 \times 5$

$V_{C}=51 \mathrm{m} / \mathrm{sec}$

After the breakage of the object the momentum conservation equation is  

$51 \times 50=20 \times 50+30 \times V_{B}$

$V_{B}=15 m / \sec (\text {downward})$

Therefore the velocity (VB) of the 30 kilogram piece is 15 m/sec downward