a rock is dropped from a height of 60 m and is in free fall. What is the velocity of the rock as it reaches the ground 3.5 seconds later?

Data given

Initial Velocity = 0 m/s

Change in distance x = 60m

Change in time = 3.5s

Acceleration due to gravity = - 9.81 m/s^2

Required

Final Velocity (vf) = ?

Solution

According to first equation of motion

Vf = Vi+gt

Put the values, we will get

Vf = 0 + (-9.81) (3.5)

-34.3 m/s (Answer)