M = mass of the girl = 53.4 kg
m = mass of skateboard = 3.55 kg
V' = velocity of the combination of girl and skateboard before she jumps forward = 0
V = velocity of the girl forward = 1.32
v = velocity of the skateboard afterward = ?
Using conservation of momentum
(M + m) V' = MV + m v
inserting the values
(53.4 + 3.55) (0) = (53.4) (1.32) + (3.55) v
v = - 19.86
Explanation:
Let the mass of two objects be m. Both objects move along the same line in opposite directions. Let v and u₂ are speeds of both objects before collision.
After the collision, both objects stick together and move with the speed of 0.1 V the direction of the velocity of the first mass before the collision.
Using the conservation of momentum as :
On solving above equation,
So, the speed of the second mass before the collision is 0.8 v. The negative sign shows that the it moves in opposite direction. Hence, this is the required solution.