Question

A shell is flying at a speed of 72Km/h. It explodes into two piece, one piece of mass 15kg stops. Call. the velocity of the other piece.​

Answer 1

Answer:

$\sf{\pink{Velocity\:of\:the\:other\:piece\:=\:32\:m\:per\:sec}}$

Explanation:

GIVEN :

• Mass of the shell, M = 40 kg
• Speed of the shell, u = 72 km/h

TO FIND :

• Velocity of the other piece.

SOLUTION :

Converting the units :

→$\sf{72\:\times\:{\dfrac{5}{18}}}$

→ $\sf{4\:\times\:5}$

→ $\sf{20\:m\:per\:\sec}$

Initial momentum of the shell :

→$\sf{P_i\:=\:}$ $\sf{M\:\times\:u}$

→ $\sf{40\:\times\:20}$

→ $\sf{800}$

•°• Initial momentum, $\sf{P_i}$ is 800 kg/ms.

After breaking :

Masses of the parts are :

• 15 kg
• 25 kg

The 15 kg piece stops.

Let the speed the speed of other piece be 'v'

Total momentum after breaking apart :

→$\sf{P_f\:=\:15\:\times\:0\:+\:25\:\times\:v}$

→ $\sf{0\:+\:25v}$

→$\sf{P_f\:=\:25v}$

•°• Total (final) momentum, $\sf{P_f\:=\:25v}$

$\sf{Acc^n\:to\:the\:law\:of\:conservation\:of\:momentum:}$

→$\sf{P_f\:=\:P_i}$

→ $\sf{25v\:=\:800}$

→ $\sf{v\:=\:{\dfrac{800}{25}}}$

→ $\sf{v\:=\:32}$

$\bold{\boxed{\tt{\red{\therefore{Velocity\:of\:the\:other\:piece\:=\:v\:=32\:m\:per\:sec}}}}}$