An inclined plane is one of the six simple machines defined by early scientists that are used with reference to physics or mechanics. The other five are levers, pulleys, screws, wedges, and wheels and axles. These simple machines were designed to magnify or redirect force in such a way as to maximize the amount of work they could accomplish.

Simply put, an inclined plane is an object that has a flat surface and is slanted at a fixed angle. The mechanical advantage it provides is a reduced amount of force required to move objects between locations with different elevations. Without the inclined plane, moving an object vertically, would require much more force. Additionally, the inclined plane, can help move objects safely downward.

Let's take a child's slide on a playground, for instance. If the child is on a platform above the ground and were to drop off of the platform straight down, the child has a strong likelihood of getting injured. It's true that it would be faster, but definitely not safe. If a child uses a slide, an example of an inclined plane, then the child will descend at a slower and safer rate. Similarly, if the child were to try to climb up to the top of the slide without using the inclined plane, it would require much more work, than if he walked up the slide.

An inclined plane has many applications and there are many examples of them in our daily lives. Some examples are ramps, slides, chutes, knives, and hatchets. It may seem strange that a knife would be classified as an inclined plane. However, take a close look at the blade of a knife and you will see the slope downward.

When an object is on an inclined plane, there are three main forces on the object. These forces are normal force, gravitational force, and frictional force. While air resistance is a force on the object, it is usually not considered because it's typically negligible. The normal force is the force put on the object that is perpendicular (90 degrees) to the inclined plane. The gravitational force is the force pulling the object directly below it. Lastly, the frictional force is parallel to the plane. Rather than use trial and error, you can predetermine whether an object can be moved up an inclined plane by using a formula involving these three forces, the mass of the object, and the angle of the inclined plane.