Question

a girl dropped a stone from a bridge and noticed that it is struck water in just 3 seconds what is the height of the bridge above the water level?

Answer 1

solution:-

initial velocity = 0m/s

Final velocity = 0m/s

acceleration due to gravity = 9.8m/s^2

Now, S = ut + 1/2 gt^2

= 0*3 + 1/2* 9.8 (3)^2

= 4.9 * 9

= 44.1

so,height of stone= 44.1 meter.

Answer 2

The height of the bridge above the water level is 44.1 meters.

• Height can be calculated by ,

       h = u * t + (1/2) * g * t^2

• given,

      initial velocity = 0

      time = 3 seconds

       g = 9.8 m/s^2

• Height of the bridge above the water level = 0 * 3 + (1/2) * 9.8 * 3 * 3

                    = 4.9 * 9

                    = 44.1 meter