A 11 g toy car moving to the right at 25 cm/s has a head-on nearly elastic collision with a 23 g toy car moving in the opposite direction at 31 cm/s. After colliding, the 11 g car moves with a velocity of 51 cm/s to the left. Find the speed of the second car after the collision. Answer in units of cm/s.

v' = 5.35 m/s

Explanation:

given,

mass of toy car 1, m = 11 g

speed of car 1 in right direction, u = 25 cm/s

mass of toy car 2, M = 23 g

speed of car 2 in left direction, u' = 31 cm/s

after collision

Speed of car 1 in left direction, v = 51 cm/s

speed of car 2, v' = ?

using conservation of momentum

m u + M u' = m v + M v'

taking motion in right direction as positive

11 x 25 + 23 x (-31) = 11 x (-51) + 23 v'

23 v' - 561 = - 438

23 v' = 123

v' = 5.35 m/s

Speed of second car is 5.35 m/s in right direction.