Question

A ball of mass 0.484 kg moving east (+xdirection) with a speed of 3.76 m/s collides head-on with a 0.242 kg ball at rest. Assume that the collision is perfectly elastic.    A)What is be the speed of the 0.484-kg ball after the collision? B)What is be the direction of the velocity of the 0.484-kg ball after the collision? C)What is the speed of the 0.242-kg ball after the collision? D)What is the direction of the velocity of 0.242-kg ball after the collision?

Answer 1

let the final velocity of 0.484 Kg ball is v1

final velocity of 0.242 kg ball is v2

Now, using conservation of momentum during collision ,

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

0.484 * v1 + 0.242 * v2 = 0.484 * 3.76 -----(1)

as the collision is elastic ,

coefficient of restitution = 1

3.76 = v2 - v1 ----(2)

solving 1 and 2

v1 = 1.25 m/s

v2 = 5.01 m/s

A) the speed of 0.484 kg mass is 1.25 m/s

B) direction of velcity is east direction

c)

speed of 0.242 kg mass is 5.01 m/s after the collision

d)

direction of velocity is east direction