Respuesta :

Answer:

V = a * t      for uniformly accelerated motion starting at zero speed

V = 4 s * 9.8 m/s^2 = 39.2 m/s

S = V0 t + 1/2 a t^2 = 1/2 a t^2

S = 1/2 * 9.8 m/s^2 * 16 s^2 = 78.4 m

Check:

Average speed = 39.2 / 2 = 19.6 m/s

S = 4 * 19.6 = 78.4 m