Question

a cannon of mass 1200kg, located on a smooth horizontal platform fires a shell of mass 300kg in horizontal direction with a velocity of 400m/s.find the velocity of the cannon after it is shot
class 9th ​

Answer 1

Given :

Mass of the cannon = 1200kg

Mass of the shell = 300kg

Velocity of shell = 400m/s

To Find :

Recoil velocity of the cannon.

Solution :

❖ Since no net force acts on the system, linear momentum of whole system is conserved.

• We know that momentum is measured as the product of mass and velocity.
• It is a scalar quantity having only magnitude.
• SI unit : N s

Initial momentum of the whole system will be zero.

$\sf:\implies\:P_{Initial}=P_{Final}$

$\sf:\implies\:0=mv+MV$

• m and M denotes masses of shell and cannon respectively.
• v and V denotes velocities of shell and cannon respectively.

By substituting the given values;

$\sf:\implies\:0=(300)(400)+1200V$

$\sf:\implies\:1200V=-120000$

$\sf:\implies\:V=-\dfrac{120000}{1200}$

$:\implies\:\underline{\boxed{\bf{\orange{V=-100\:ms^{-1}}}}}$

Note : Negative sign shows opposite direction.

Answer 2

$\huge{\underline{\underline {\mathtt{\purple{Hlw}\pink{Mate}}}}}$

$\Large\green{Given:}$

Mass of the cannon = 1200kg

Mass of the shell = 300kg

Velocity of shell = 400m/s

$\Large\green{To \:Find:}$

Velocity of the cannon after it is shot

$\Large\blue{Solution:}$

No net force acts on the system, linear momentum of whole system is conserved.

We know,

momentum (p) = mass (m) × velocity (v) [or] p = mv

Let initial momentum of the whole system will be zero.

$\sf\implies\: P_{Initial}=P_{Final}$

$\sf\implies\:0=mv+MV$

Substituting the given values;

$\sf\implies\:0=(300)(400)+1200V$

$\sf\implies\:1200V=-120000$

$\sf\implies\:V=-\dfrac{120000}{1200}$

$\huge{\underline{\underline {\mathtt{\purple{ V = -100\:ms^{-1}}\pink{}}}}}$

$\Large\fbox\red{Mark\: as\:Brainliest}$