Question

Standing on the surface of the Earth you drop a rock down a well and it falls for 5 seconds before hitting the bottom. How fast is it moving when it hits the bottom of the well? Neglect air resistance.

1) 10 m/s
2) 50 m/s
3) It depends on what shape it is.
4) 15 m/s
5) It depends on how heavy it is.

Answer 1

The rock will be moving at approximately 49 m/s when it hits the bottom of the well after falling for 5 seconds, assuming no air resistance. The correct choice from the options given is 50 m/s.

Step-by-step explanation:

To determine how fast the rock is moving when it hits the bottom of the well after falling for 5 seconds, we can use the formula for the velocity of an object in free fall, which is v = gt, where v is the final velocity, g is the acceleration due to gravity (9.8 m/s² on Earth), and t is the time the object has been falling. In this case:

v = (9.8 m/s²)(5 s) = 49 m/s

The velocity will be approximately 49 m/s when it hits the bottom, assuming no air resistance and neglecting the initial velocity since the rock is dropped, not thrown. The shape and the mass of the rock do not affect its velocity in this scenario due to the universality of free fall in the absence of air resistance. Hence, the closest answer from the options provided is 50 m/s.