Question

Two objects, each of mass 1.5 kg, are moving in the same straight line but in opposite directions. The
velocity of each object is 2.5 ms before the collision during which they stick together. What will be the
velocity of the combined objects after collision ? in this question its sense that each object mass is 1.5kg then why we always take both mases of object is same​

Answer 1

Mass of one of the objects, m1 = 1.5 kg

Mass of the other object, m2 = 1.5 kg

Velocity of m1 before collision, u1 = 2.5 m/s

Velocity of m2, moving in opposite direction before collision, u2 = ˆ’2.5 m/s

Let v be the velocity of the combined object after collision. By the law of conservation of momentum,

Total momentum after collision = Total momentum before collision,

Or, (m1 + m2) v = m1u1 + m2u2

Or, (1.5 + 1.5) v = 1.5 — 2.5 +1.5 — (€“2.5) [negative sign as moving in opposite direction] Or, v = 0 m/s