Answer:
Mc = 900 Kg
Uc = 28 ms^-1
Md = 70 Kg
Ud = 0
We want Vd
Vc = Vd
This situation is elastic momentum
[tex]m _{c}u _{c}+ m _{d}u _{d} = m _{c}v _{c} + m _ dv _{d} \\ (900 \times 28) + (70 \times 0) = (900 \times v _{d} ) + (70 \times v _{d}) \\ 25200 = (900 + 70)v _{d} \\ 25200 = 970v _{d} \\ v _{d} = \frac{25200}{970} \\ v _{d} = 26 \: m {s}^{ - 1} [/tex]