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 $2.5\ m s^{-1}$ before the collision during which they stick together. What will be the velocity of the combined object after collision?

AcademicPhysicsNCERTClass 9

Given: 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 $2.5\ m s^{-1}$ before the collision during which they stick together.

To do: To find the velocity of the combined object after the collision.

Solution:

Mass of the object first $m_1=1.5\ kg.$

The velocity of the first object $v_1=2.5\ ms^{-1}$

Mass of the second object $m_2=1.5\ kg.$

The velocity of the second object $v_2=-2.5\ ms^{-1}$ [-ve sign indicates opposite direction]

According to the conservation of momentum,

$m_1v_1+m_2v_2=(m_1+m_2)V$   [Let $V$ be the final velocity of the combined object]

Or $1.5\times2.5+1.5\times(-2.5)=(1.5+1.5)V$

Or $0=3V$

Or $V=0$

Thus, the velocity of the combined object after the collision is zero.

raja
Updated on 10-Oct-2022 13:22:33

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