Answer:
a = 1.66 m /s²
Explanation:
This is a kinematics exercise
v = v₀ + a t
x = v₀ t + ½ a t²
we solve for the initial velocity in the first equation and substitute in the second
v₀ = v - at
x = (v- at) t + ½ a t²
x = vt - a t² + ½ a t²
x = v t - ½ a t²
we seek acceleration
a = (v t -x) 2 / t²
let's calculate
a = (15 6 - 60) 2/6²
a = 1.66 m /s²