Question

7. Two bodies A & B of mass 3kg & 2kg respectively Moving with initial velocity 5m/s & 3m/s collides with each other such that both moves with the same velocity after collision. Find the velocity though which both will move together.​

Answer 1

Given :

Two bodies of masses 3kg and 2kg are moving with velocity 5m/s and 3m/s in same direction.

They collide with each other and move together$.$

To Find :

We have to find final velocity of the combined mass$.$

Concept :

Since, No net force acts on the whole system, we can apply concept of momentum conservation. ☃

Initial system of whole system will be equal to the final momentum of whole system.

Calculation :

$\dashrightarrow\tt\:m_Au_A+m_Bu_B=(m_A+m_B)\times v$

$\dashrightarrow\tt\:(3\times 5)+(2\times 3)=(3+2)\times v$

$\dashrightarrow\tt\:15+6=5v$

$\dashrightarrow\tt\:v=\dfrac{21}{5}$

$\dashrightarrow\underline{\boxed{\bf{\purple{v=4.2\:ms^{-1}}}}}\:\orange{\bigstar}$

Answer 2

Given ,

The two bodies A & B of mass 3kg and 2kg are moving with velocity 5 m/s and 3 m/s

We know that ,

The law of conservation of linear momentum states that during any collision if the external force is zero then the total momentum is conserved

Thus ,

(3 × 5) + (2 × 3) = v(3 + 2)

15 + 6 = 5v

21 = 5v

v = 21/5

v = 4.2 m/s

$\therefore$ The common velocity of both bodies is 4.2 m/s