Two bodies A and B move toward each other with speeds of 80 cm/s and 40 cm/s, respectively. The mass of A is 140 g and that of B is 60 g. After a head-on, perfectly elastic collision, the speed of B is

The speed of body B after collision is 128 cm/s

Explanation:

Given;

initial speed of body A, = 80 cm/s (forward direction)

initial speed of body B, = - 40 cm/s (backward direction)

mass of body A, = 140 g

mass of body B, = 60 g

let the speed of body A after collision =

let the speed of body B after collision =

Apply the principle of conservation of linear momentum;

One direction velocity;

substituting the value of Va in the first equation, we will have;

Therefore, the speed of body B after collision is 128 cm/s