Question

The equation y=-16x²+32x represents the height of ball x seconds after being kicked. Use a graph to determine the time when the ball is kicked and when it hits the ground.

a. Os
b. 1s
c. 2 s
d. 16 s
e. 32 s

Answer 1

The ball is in the ground at the times 0s and 2s, so the correct options are a and c.

when the ball is kicked and when it hits the ground?

The values of x at which y = 0 are the points where the ball is in the ground.

So we only need to find the roots, the equation is:

y=-16x²+32x

We can rewrite this as:

y = (-16x + 32)*x

This is zero when either of the factors is zero, so:

if x = 0

if (-16x + 32) = 0

Solving the second one we get:

16x = 32

x = 32/16

x = 2

So the correct options are a and c.