Question

Object A of mass M is moving east at speed v. It collides with object B of mass 2M that was initially at rest. The motion of the objects before and after the collision is along the same line. After the collision, object A is moving west at a speed of v/3. What is the speed of object B immediately after the collision?

Answer 1

The speed of object B immediately after the collision with object A, originally moving east, is (2/3)v when object A reverses direction and moves west at v/3.

Step-by-step explanation:

The student's question involves a collision between two objects where linear momentum conservation applies. In this scenario, object A of mass M collides with object B of mass 2M. The principle of conservation of linear momentum states that the total momentum before the collision must be equal to the total momentum after the collision, if no external forces are acting on the system. Given that object A is moving at speed v and object B is initially at rest, we can set up the following equation based on momentum conservation:

M * v + 2M * 0 = M * (-v/3) + 2M * Vb

Where Vb is the velocity of object B after the collision. Simplifying and solving for Vb:

Mv = -M(v/3) + 2MVb

Mv + M(v/3) = 2MVb

4/3Mv = 2MVb

Vb = (4/3Mv) / (2M)

Vb = (2/3)v

Hence, the speed of object B immediately after the collision is (2/3)v.