Question

Two objects A and B are moving along the same straight line in opposite directions with velocities 10 m/s and 5 m/s respectively. They collide during which they stick to each other. If mass A is 1.5 kg and mass of B is 1 kg, what is the velocity of the combination?

Answer 1

Given :

▪ Mass of A = 1.5kg

▪ Mass of B = 1kg

▪ Velocity of A = 10mps

▪ Velocity of B = -5mps

[Negative sign shows opposite direction]

To Find :

▪ Velocity of the combination after collision.

Concept :

→ Here, no external force acts on the system so, we can easily apply concept of 'momentum conservation' to solve this type of questions.

Calculation :

$\dashrightarrow\sf\:M_AV_A+M_BV_B=(M_A+M_B)V\\ \\ \longrightarrow\sf\:(1.5\times 10)-(1\times 5)=(1.5+1)V\\ \\ \dashrightarrow\sf\:15-5=2.5V\\ \\ \longrightarrow\sf\:10=2.5V\\ \\ \dashrightarrow\sf\:V=\dfrac{10}{2.5}\\ \\ \longrightarrow\underline{\boxed{\bf{\red{V=4\:mps}}}}\:\gray{\bigstar}$