Law of the Lever
Table of Contents
ToggleA lever is a rigid, usually rod-shaped body with a rotatable fixed axis. A distinction is made here between a one-sided and a two-sided lever.
In a first class lever, the fulcrum is located between the load and the effort. When the fulcrum is closer to the load, then less effort is needed to move the load
Second-class levers have the load between the effort and the fulcrum. As an example you see a wheelbarrow. The wheel is the fulcrum, the handles take the effort, and the load is placed between the wheel and the effort.
Exercise
A load of 10 kg is pulled up by 10 m using a crank with a crank shaft of 20 cm diameter. The diameter d1 of the outer l rings 40 cm.
- What is the minimum force F1 required to lift the load?
- How long is the distance s1 that you have to pull on the rope?
- How much work has been done here?
1.: F1 × r1 = Fweight × r2 with Fweight = m × g = 10 kg × 9,81 m/s2 = 98,1 N F1 = (Fg × r2) / r1 = (98,1 N × 0,1 m) / 0,2 m = 49,05 N 2.: s1 = (Fg × height) / F1 = (98,1 N × 10 m ) / 49,05 m = 20 m 3.: W = FG × height = 98,1 N × 10 m = 981 Nm