A girl throws a stone from a bridge. Consider the following ways she might throw the stone. The speed of the stone as it leaves her hand is the same in each case.
Case A: Thrown straight up.
Case B: Thrown straight down.
Case C: Thrown out at an angle of 45° above horizontal.
Case D: Thrown straight out horizontally.
In which case will the speed of the stone be greatest when it hits the water below if there is no
Significant air resistance?
A) Case A
B) Case B
C) Case C
D) Case D
E) The speed will be the same in all cases.

Question

Quizplus · Accepted Answer

In the absence of significant air resistance, all objects near the Earth's surface accelerate downward at the same rate regardless of their initial motion. Thus, the speed of the stone when it hits the water will be the same in all cases, as the vertical component of its velocity will increase at the same rate due to gravity.

A Girl Throws a Stone from a Bridge