![]() The angle (the steepness of the inclined plane) determines how much effort is needed to raise the weight. According to Bob Williams, a professor in the department of mechanical engineering at the Russ College of Engineering and Technology at Ohio University, an inclined plane is a way of lifting a load that would be too heavy to lift straight up. The inclined plane is simply a flat surface raised at an angle, like a ramp. ![]() We have made a trade-off in which we doubled the distance we had to move the lever, but we decreased the needed force by half in order to do the same amount of work. ![]() However, we would have to push the end of the lever down 4 feet (1.2 m) in order to lift the weight 2 feet. However, if we were to use a 30-foot (9 m) lever with one end under the weight and a 1-foot (30.5 cm) fulcrum placed under the beam 10 feet (3 m) from the weight, we would only have to push down on the other end with 50 lbs. of force on the weight in the upward direction for a distance of 2 feet, and we have done 200 pound-feet (271 Newton-meters) of work. (45 kilograms) weight 2 feet (61 centimeters) off the ground. The mechanical advantage of the lever depends on the ratio of the lengths of the beam on either side of the fulcrum.įor example, say we want to lift a 100-lb. The lever consists of a long beam and a fulcrum, or pivot. His Law of the Lever states, "Magnitudes are in equilibrium at distances reciprocally proportional to their weights," according to " Archimedes in the 21st Century (opens in new tab)," a virtual book by Chris Rorres at New York University. The genius of Archimedes was to realize that in order to accomplish the same amount or work, one could make a trade-off between force and distance using a lever. ![]() While it may be a bit of an exaggeration, it does express the power of leverage, which, at least figuratively, moves the world. "Give me a lever and a place to stand, and I'll move the world." This boastful claim is attributed to the third-century Greek philosopher, mathematician and inventor Archimedes. As indicated by the math, the main benefit of machines is that they allow us to do the same amount of work by applying a smaller amount of force over a greater distance. It also takes twice as much work to lift the same object twice as far, according to Auburn University (opens in new tab). To lift an object that is twice as heavy, it takes twice as much work to lift it the same distance. For example, to lift an object, we must do work to overcome the force due to gravity and move the object upward. Mathematically, this is expressed as W = F × D. When a force is applied over a distance, it produces work. Mechanical advantage is the trade-off between force and distance." In the following discussion of the simple machines that increase the force applied to their input, we will neglect the force of friction, because in most of these cases, the frictional force is very small compared to the input and output forces involved. Kolodner and her co-authors write, "Machines provide mechanical advantage to assist in moving objects. In their book " Moving Big Things (opens in new tab) ," Janet L. ![]() The other five machines all help humans increase and/or redirect the force applied to an object. Alternatively, a long handle can be attached to the axle to achieve a similar effect. If a wheel is attached to an axle, and a force is used to turn the wheel, the rotational force, or torque, on the axle is much greater than the force applied to the rim of the wheel. In addition to reducing friction, a wheel and axle can also serve as a force multiplier. – Perpetual motion machines: Working against physical laws ![]()
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