A cannonball is fired from a cannon. The equation below gives the height of the cannonball in feet after t seconds. When does the cannonball reach the ground?

Question

A cannonball is fired from a cannon. The equation below gives the height of the cannonball in feet after t seconds. When does the cannonball reach the ground?

A. 5.75 seconds (-410)

B. 1.43 seconds (-0.1184)

C. 1.00 second (8)

D. 0.18 seconds (7.0816)

I included all of the totals I received when I entered them into the equation. I think the Answer is either b or c.

Answer 1

Klauss,

You want to find the time when h(t)=0. If you set h(t)=0 the above becomes a standard quadratic equation.

The positive root is t= 1.425 sec so think the answer is B

Jim