Question

A very small steel marble is shown rolling at a constant speed on a horizontal table. The marble leaves the table at N, falls, and hits the ground at M. This is illustrated in the diagram below which is drawn to scale. Calculate the time it took the marble to travel from P to M.

Picture included

Answer 1

The initial velocity in the vertical direction is zero. The marble will take as long to reach the ground as an object dropped vertically from the same height. To find the time:\[\color{green}{t = \sqrt\frac{2d}{g}}\]
Make sure d is converted to metres before you do the calculation.

Answer 2

so d would be 40?

Answer 3

or .4 m?