Question

A heavy stone is thrown from a cliff of height $h$ with speed $v$. The stone will hit the ground with maximum speed if it is thrown:

• A. vertically downward
• B. vertically upward
• C. horizontally
• D. the speed does not depend on the inital direction

Answer 1

Answer: (D)

the speed does not depend on the inital direction

Speed at the time of hit is calculated as magnitude of velocity at that instant.

And velocity has two components, horizontal and vertical whose value depend on the angle but their $resultant$ will be same.

In other words the speed at moment of hit can be calculated by conservation of mechanical energy, as height is constant so decrease in potential energy or increase in kinetic energy will be same whatever the angle of projection be.

Option D is correct.

Also, speed is scalar it does not depend on direction.

Note- if throwing it vertically downward then the vertical component will be greatest but resultant of horizontal and vertical will be always same for any angle.