Here\'s a side view of a different kind of ladder. This one hooks over a bar, an
ID: 1419460 • Letter: H
Question
Here's a side view of a different kind of ladder. This one hooks over a bar, and leans at an angle of 20degree with its legs resting on the floor. (Like at the library/bookstore ...) Suppose the ladder is 3 meters long, including the hook at the end, and it has a mass of 10kg. The bottom of the ladder is designed to slide easily on the floor, to make it easy to reposition the ladder, so let's suppose that the friction with the floor is small enough to ignore. If someone of mass 50kg is standing on the middle rung (1.5 meters up), estimate the size of the force between the hook and the bar.Explanation / Answer
Applying equilibrium of moment
=> 10 * 9.8 * 1.5 * sin20 + 50 * 9.8 * 1.5 * sin20 = F * 3 * cos20
=> F = 107 N
=> size of force between hook and bar = 107 N