Projectiles: 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.

Question

Quizplus · Accepted Answer

The time it takes for a projectile to hit the ground only depends on the initial vertical velocity and the height of the building, not on the initial horizontal velocity or angle of projection. Since both rocks are dropped from the same height and experience no air resistance, they will hit the ground at the same time, regardless of Len's initial velocity or angle of projection. Therefore, the correct answer is A) They hit at the same time.

Projectiles: Jan and Len Throw Identical Rocks Off a Tall