the question is:
You shoot an arrow in the air. It falls to earth. Its height (in feet) after t seconds is h(t)=80t−16t^2. What is its velocity as it hits the ground? (Your answer should be negative since the arrow is going down.)
I know the first step is to find the derivative, which is: h'(t) = -32t + 80. I thought that next I was supposed to set the function equal to "0" and solve for "t", but when I do this, I end up with t=2.5, but when I answer it this way (or negative) it's incorrect.
You shoot an arrow in the air. It falls to earth. Its height (in feet) after t seconds is h(t)=80t−16t^2. What is its velocity as it hits the ground? (Your answer should be negative since the arrow is going down.)
I know the first step is to find the derivative, which is: h'(t) = -32t + 80. I thought that next I was supposed to set the function equal to "0" and solve for "t", but when I do this, I end up with t=2.5, but when I answer it this way (or negative) it's incorrect.