Word Question

Question

I don't understand where to plug everything into this one. I need help please.

 

The height of a rocket thrown upward with a velocity of 32 ft/sec from the roof of a 20 feet tall building is modeled by 

 

h(t) = -16t^2 + 32t + 20

Here, h is the height of the object off the ground (in feet), t (seconds) after the object is thrown.

 

a. When does the rocket reach its maximum height above the ground?

 

b. What is its maximum height?

Answer 1

If you are taking a calculus-based physics course, take the derivative of the position function and you will get the velocity. Now solve for when the velocity is 0. This will find the time at the max height. Now plug that time into the given position equation and you will find the max height.

If you are not taking a calculus based class, let's take a step back.
You are given an initial velocity. What is the final velocity at max height? What is the acceleration in ft/s^2? Plug those in to the vf = v0 +at equation.

Now you have the time it takes to get to the max height.

Plug this time into the given equation to find the max height.

I hope this helps!