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

Answer:

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

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)

$1.5\times11.2+0=1.5\times v_{1}+4.5\times 5.6$

$v_{1}=\dfrac{1.5\times11.2-4.5\times 5.6}{1.5}$

$v_{1}=-5.6\ m/s$

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