Apenny is dropped from rest from the top of the sears tower in chicago. considering that the height of the building is 427m and ignoring air resistance, find the speed with which the penny strikes the ground

We have the equation of motion , where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.

Here s = 427 m, u = 0 m/s, a = 9.81

Substituting

Now we have v = u+at, where v is the final velocity

Here u = 0 m/s, a= 9.81 and t = 9.335 seconds

Substituting

     v = 0+9.8*9.335 = 91.483 m/s

The speed with which the penny strikes the ground = 91.483 m/s.

magnitude and direction