contestada

During a fireworks display, a starburst rocket is shot upward with an initial velocity of 34.5 m/s from a platform 3.2 m high. The height, in metres, of the rocket after t seconds is represented by the function h(t) = - 4.9t2 + 34.5t + 3.2.

d) Sometime the rockets malfunction and do not explode. How long would it take for an unexploded rocket to return to the ground?

Respuesta :

Answer:

7.13 seconds to the nearest hundredth.

Step-by-step explanation:

When it returns to the ground its height is 0, so we write:

- 4.9t2 + 34.5t + 3.2 = 0Solving for time t:

t = [-34.5 +/- sqrt(34.5^2 - 4*-4.9* 3.2)] / -9.8

 = 7.132, -0.092

We ignore the negativs

so the required time

= 7.132 seconds.