Question

6. Object A has a mass of 3 kg and collides with the 2 kg object B which is moving at 4 m/s. After the collision object A moves with a velocity of -3 m/s, and object B has a velocity of 5 m/s. What is the initial velocity of object A?

Answer 1

Step-by-step explanation:

Given: Mass of object A,
`m_(A) = 3 kg`,

Mass of object B,
`m_(B) = 2 kg`,

The velocity of object A before the collision,
`u_(A) = ? m/s`,

The velocity of object A after the collision,
`v_(A) = -3 m/s`,

The velocity of object B before the collision,
`u_(B) = 4 m/s`,

The velocity of object B after the collision,
`v_(B) = 5m/s`.

From the law of conservation of linear momentum,

total momentum of the system before collision = total momentum of the system after collision

Hence,
`m_(A) u_(A) + m_(B) u_(B) = m_(A) v_(A) + m_(B) v_(B) \\`

Inserting the values,

`(3*u_(A))+(2 *4) = (3*-3)+(2*5)\\ 3*u_(A)=-7\\u_(A)=-7/3 m/s`

Hence, the initial velocity of object A is -7/3 m/s.