Question

Object A with a mass of 1.5 kilograms is moving with a velocity of +11.2 meters/second (moving in the +x direction). It has a perfectly elastic collision with stationary object B that has a mass of 4.5 kilograms. After the collision, object B travels with a velocity of +5.6 meters/second. What is the final velocity for object A?

Answer 1

Hi, the final velocity for object A is -5.6 m/s 

Answer 2

The final velocity for object A is 5.6 m/s in opposite direction.

Step-by-step explanation:

Given that,

Mass of object A=1.5 kg

Initial velocity of Object A = 11.2 m/s

Mass of object B = 4.5 kg

Initial velocity of object B= 0 because object B is stationary

Final velocity of object B = 5.6 m/s

Using conservation of momentum

`m_(1)u_(1)+m_(2)u_(2)=m_(1)v_(1)+m_(2)v_(2)`....(I)

Where, m₁= mass of object A

u₁ = initial velocity of object A

v₁ = final velocity of object A

m₂= mass of object B

u₂ = initial velocity of object B

v₂ = final velocity of object B

we substitute the value in equation (I)

`1.5*11.2+0=1.5* v_(1)+4.5* 5.6`

`v_(1)=(1.5*11.2-4.5* 5.6)/(1.5)`

`v_(1)=-5.6\ m/s`

Hence, The final velocity for object A is 5.6 m/s in opposite direction.