Question

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?

Answer 1

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)