Question

The drop that riders experience on Dr. Doom’s Free Fall can be modeled by the quadratic function, h(t) = −9.8t2−5t + 39

Answer 1

Answer:

a) 39 meters

b) t = 1.8 seconds

Step-by-step explanation:

a)

To find the starting height of the riders, we just need to use the value of t = 0 in the equation of h(t):

h(0) = -9.8*0^2 - 5*0 + 39

h(0) = 39 meters

b)

To find when the height will be equal 0, we just need to use the value of h(t) = 0 and then find the value of t:

0 = -9.8*t^2 - 5*t + 39

Delta = b^2 - 4ac = 25 + 4*39*9.8 = 1553.8

sqrt(Delta) = 39.418

t1 = (5 + 39.418)/(-2*9.8) = -2.2662 s (A negative value for the time is not suitable for the problem)

t2 = (5 - 39.418)/(-2*9.8) = 1.756 s

Rounding to nearest tenth, we have t = 1.8 s