Two kids are roller skating. Amy, with a mass of 55 kg, is traveling forward at 3 m/s. Jenny, who has a mass of 40 kg, is traveling in the opposite direction at 5 m/s. They crash into each other and hold onto each other so that they move as one mass. How fast are they traveling?
Accepted Solution
A:
Answer: 7/19 m/sec in Jenny's direction
Explanation: Assume that the direction of motion of Amy is the default direction given the positive sign. Therefore. Jenny's direction will be given a negative sign. The law of conservation of momentum states that: "For a closed system, momentum is conserved. This means that: M1V1 + M2V2 = M3V3 where: M1 is Amy's weight = 55 kg V1 is Amy's velocity = 3 m/sec M2 is Jenny's weight = 40 kg V2 is Jenny's velovity = -5 m/sec M3 is their final mass = 55+40 = 95 kg V3 is their final velocity that we want to find
Substitutw with the givens in the above equation to get the final velocity as follows: (55)(3) + (40)(-5) = 95V3 165 - 200 = 95V3 -35 = 95 V3 V3 = -7/19 m/sec This means that their final velocity is 7/19 m/sec in Jenny's direction