find length given equation in standard form

Question

equation h(t)=-16(squared)+160t is given. they ask you to find the length of a rock given the equation

Answer 1

I think the function is h(t)=-16t²+160t.

This looks like the trajectory of a projectile (rock) thrown into the air and falling under gravity with negligible air resistance. h(t)=-16(t²-10t)=-16(t²-10t+25-25)=-16(t-5)²+400.

I guess h is measured in feet and time in seconds. After 5 seconds we have h(5)=400 feet, the maximum height of the projectile. My guess is that 400ft is what is referred to as the "length of the rock", which I understand to be the maximum height of the rock (the projectile).