Question

Two masses collided at the same speed of 3.4 m/s and then bounced back at opposite directions. if their final speed is equal to 1.2 m/s for object (a) and 1.4 m/s for object (b) | if the mass of object (a) is 0.5 kg - the second mass will be equal to__________

A) 0.33 kg
B) 0.44 kg
C) 0.55 kg

Answer 1

see note below

Step-by-step explanation:

Momentum = P = mv

Conservation of momentum: total momentum before the collision must equal total momentum after the collision.

Assume the direction of mass 1 before the collision is the POSITIVE direction. Assume masses are initially moving toward each other for a head-on collision.

let m = mass of second object

(3.4 m/s)(0.5 kg) - (3.4 m/s)m = (-1.2 m/s)(0.50 kg) + (1.4 m/s)m

1.7 kg·m/s + 0.6 kg·m/s = (1.4 m/s)m + (3.4 m/s)m

2.3 kg·m/s = (4.8 m/s)m

m = (2.3 kg·m/s) / (4.8 m/s) = 0.48 kg

none of the choices shown match my answer, but the closest one is B) 0.44 kg