- #1

OVB

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I do this:

M = mass of father

V = velocity of father

0.5MV^2 = 0.5(0.5mv^2)

2MV^2 = mv^2

(4m)V^2 = mv^2

4V^2 = v^2

2V = v

0.5M(V+1)^2 = 0.5m(2V)^2

(V+1)^2 = 4V^2

V^2 + 2V + 1 = 4V^2

-3V^2 +2V + 1 = 0

(3V +1) (-V + 1)

V = 1, -1/3

so V = 1 m/s

However, my book says the speeds are 2.4 m/s and 4/8 m/s for father and son, respectively. What am I doing wrong?