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
where h is height in meters and t is time in seconds.

Determine the actual solution to the questions below. Use the previous question to assist you.

(a) What is the starting height of the riders?

The starting height of the riders is meters.

(b) According to the function, when will the height of the riders equal 0? Round to the nearest tenths place. *hint: find the solution(s).

The height of the riders will equal 0 at seconds.

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