Ryan throws a tennis ball straight up into the air. The ball reaches its maximum height at 2 seconds. The approximate height of the ball x seconds after being thrown is shown in the table.

Question

Which equation models the motion of the ball?

y = –17(x)(x – 4)
y = –16(x)(x – 4)
y = –16(x – 2)2 + 68
y = –17(x – 2)2 + 68

Answer 1

The equation that models the motion of the ball is y = -16(x - 2)^2 + 68.

This is because the ball reaches its maximum height at 2 seconds, which means that the vertex of the parabola is at the point (2, 68). This equation represents a parabolic function that opens downwards and has a vertex at (2, 68).