Answer:
- 8 m/s
Step-by-step explanation:
average velocity = Δx /Δt = [x2 - x1] /[t2 - t1]
t2 = 2 sec, t1 = 0 sec
x2 = x(2) = 20 - 4 * 2² = 20 - 16 = 4 m
x1 = x(1) = 20 - 4*0² = 20 m
average velocity = Δx /Δt = [4 m - 20 m] /[2 s - 0 s] = - 16 m/ 2 s= - 8 m/s