Answer:
The speed of stone while hitting the ground in all the three cases will be same .
Step-by-step explanation:
The speed of stone while hitting the ground in all the three cases will be same .
They all will have same initial kinetic energy because they have same initial speed . Kinetic energy of an object does not depend upon the direction of velocity of the object .
They will all gain kinetic energy due to loss of height .Since they all fall from the same height , gain of kinetic energy in all the three cases will also be same .
Hence final kinetic energy will be same when they hit the ground .
Hence they all have same speed while hitting the ground .