Question

2.  A 0.768 kg object is moving with a velocity of 2.53 m/s.  A 0.532 kg moving object

     hits it.  After collision, the 0.768 kg object has a velocity of 3.22 m/s and the 0.532 kg

     object has a velocity of 0.636 m/s.  What was the velocity of the 0.532 kg object

     before collision?  (All motion is 1-D; friction can be ignored.)

Answer 1

here,

the mass of object 1 ,m1 = 0.768 kg

the mass of object 2 ,m2 = 0.532 kg

the initial velocity of object 1 , u1 = 2.53 m/s

the final velocity of object 1 , v1 = 3.22 m/s

the final velocity of object 2 , v2 = 0.636 m/s

let the initial velocity of object 2 be u2

using conservation of momentum

m1 * u1 + m2 * u2 = m1 * v1 + m2 * v2

0.768 * 2.53 + 0.532 * u2 = 0.768 * 3.22 + 0.532 * 0.636

solving for u2

u2 = 1.63 m/s

the initial velocity of object 2 is 1.63 m/s