After how many seconds did the driver reach the surface area

Question

h(t)= -16r² + 8r+ 80

Answer 1

The equation you provided describes the launch of a projectile. Was the vehicle catapulted at the edge of the cliff as a projectile? If so, set

 

h(t) = 0

 

and solve the quadratic equation for t.  You will get a positive and a negative solution.  The positive solution is the answer.