Final answer:
The second stone must have been thrown downwards and with an initial velocity that is greater than zero to reach the ground at the same time as the first stone that was dropped; thus the answer is: (c) Faster than the first stone.
hence the correct answer is: (c) Faster than the first stone.
Step-by-step explanation:
The student asks about the velocity of a second stone thrown from a tower 14 m high if it reaches the ground at the same time as another stone that was dropped without an initial velocity.
This is a classic physics problem related to the concepts of projectile motion and free fall.
For the stones to hit the ground at the same time, the second stone must be thrown downwards. Since the first stone is dropped with zero initial velocity, the acceleration due to gravity affects both stones equally. This means the first stone simply accelerates from rest under gravity.
However, for the second stone that was thrown to catch up and hit the ground at the same time, it must start with an initial velocity directed downwards. Therefore, the second stone must be thrown with an initial velocity that is greater than zero and is directed downward, hence the correct answer is: (c) Faster than the first stone.
The stones both have the same displacement (14 m) and are both under the influence of gravity. Ignoring air resistance, the only way for the thrown stone to hit the ground simultaneously with the dropped stone is if it had an initial speed that gives it the same time of flight as the dropping stone, but it arrives with a greater final velocity due to the initial velocity it was thrown with.
This corresponds to physics equations for motion under constant acceleration, which is the case with gravity where the only force acting on the object is due to its weight.