One way to put a ladder in place on a wall is to “walk” the ladder to the wall. One end...

One way to put a ladder in place on a wall is to “walk” the ladder to the wall. One end of the ladder is held fixed (perhaps at the base of the wall), and a person slides his hands along the ladder as he walks toward the fixed end as sketched in Figure P8.38. Anyone who has raised a ladder in this way knows that the amount of force the person must apply grows larger initially as the person moves toward the end that is fixed. Assuming the force from the person is perpendicular to the ladder, find the force the person must apply to hold the ladder at (a) an angle of 10° and (b) an angle of 20°.