Question

A basketball rolls off a deck that is 3.2 m from the pavement. The basketball lands 0.75 m from the edge of the deck. How fast was the basketball rolling?

Seema lists the given values in a chart and determines that the unknown value is vx.

A 2 column table with 2 rows. The first column is labeled Given with entries delta Y, a Subscript y Baseline, delta x. The second column is labeled Value with entries 3.2 meters, negative 9.8 meters per second squared, .75 meters.
Which describes Seema’s error?

The y and x values are switched.
The unknown is , not vx.
The value for ay is not known.
The value of y should be –3.2 m.

Answer 1

"The value of y should be –3.2 m."

Reason: the ball falls 3.2 m downward, so Δy = −3.2 m (gravity a_y = −9.8 m/s² is correct). Using Δy = ½ a_y t² gives t = sqrt(2·3.2/9.8) ≈ 0.81 s, so vx = Δx/t ≈ 0.75/0.81 ≈ 0.93 m/s.