Answer

a) Use s=ut + 1/2at² (1) t = √ (2 x 0.39m / 10 m s ^-2) (1) = 0.28 s (1)

b) s = ut (1) = 35 m s ^-1 x 0.28 s 9.8 m (1)

c) u = s/t (1) = 15 m / 0.28 s = 54 m s ^-1 (1)