Jan and Len Throw Identical Rocks Off a Tall Building

Multiple Choice

Jan and Len throw identical rocks off a tall building at the same time.The ground near the building is flat.Jan throws her rock straight downward.Len throws his rock downward and outward such that the angle between the initial velocity of the rock and the horizon is 30°.Len throws the rock with a speed twice that of Jan's rock.If air resistance is negligible,which rock hits the ground first?

A) They hit at the same time.
B) Jan's rock hits first.
C) Len's rock hits first.
D) It is impossible to know from the information given.