Abasketball 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. given: value: change in y 3.2m ay -9.8 m/s2 change in x 0.75m which describes seema’s error? a. the y and x values are switched. b. the unknown is , not vx. c. the value for ay is not known. d. the value of y should be –3.2 m.

The table is almost perfect. BUT ... since she called ay negative, that means she's calling the upward direction positive-y and the downward direction negative-y. In that case, since the ball moves downward from the deck to the pavement, the change in y should be negative 3.2 m. Everything else in her table is fine. Choice-D is the good one.

Now, regarding the speed of the ball ...
How long does it take to fall 3.2 m ?
Use the formula. D = 1/2 g T^2 .

3.2 = 4.9 T^2.

T^2 = 3.2/4.9

T = √(3.2/4.9) = 0.808 second.

The ball hit the pavement 0.808 second after it rolled off the deck. So that's also the time it took to move the 0.75 m horizontally.

Speed = distance / time

Speed = 0.75 m / 0.808 second

Speed = 0.928 meter/second .