how to get answer?

Question

A toy rocket is launched from a 5.6 m high platform in such a way that its height, h (in meters), after t seconds is given by the equation h= -4.9t^2+38.5t+5.6t. How long will it take the rocket to hit the ground? That is supposed to be -4.9tsquared

Answer 1

Your equation would tell you the height above the ground based on the number of seconds after its launch. If you have a graphing calculator, you can put the equation in and look at the table.....0 sec is 5.6 meters, 1 sec is 39.2 m (assuming you meant 5.6 instead of 5.6t ), 2sec is 63 m, 3 sec is 77 m, 4 sec is 81.2, 5 sec is 75.6 m.......finally coming down. You can continue this until you find a height of 0.

 

Or you can solve the equation what value of t do I have to plug in to give me zero?

-4.9t^2 + 38.5t + 5.6 = 0. Hope you know how to use the quadratic formula.