Answer:
9.23secs
Explanation:
Given the height of the rock modeled by the equation;
h(t)=-6.5t^2+50t
The rock falls back to the surface of the Mars at when the height is zero i.e h(t) = 0
Substitute into the formula and get the time t
h(t)=-6.5t^2+50t
0 = -6.5t^2+50t
6.5t^2 = 50t
6.5t = 50
t = 50/6.5
t = 9.23secs
Hence the rock fall back to the surface of the Mars after 9.23secs