What are 10 examples of simple machines

The simple machines

The task of simple machines

If we want to use forces in daily life, then we do not always succeed in attacking where we want, or our forces are too small. For example, if we have a flat tire, we cannot lift a car with our muscular strength or we cannot pull things towards us that are beyond our arm's reach. To solve these problems there are the so-called simple machines. A basic distinction can be made between four simple machines, which are used either individually or in conjunction with one another: the rope and the rod; the pulley and pulley; the lever; the inclined or inclined plane. Although these machines can change the amount or direction of a force, they can never reduce the work required for a certain movement.

The rope and the pole

We are familiar with the use of these simple machines from everyday life, for example when we tow a car with a rope or push a car with the help of a rod, here called a drawbar. With a rope or a rod you cannot change the direction of the force or its size, as they only transmit it rigidly.

Rope and rod shift the point of application of a force and leave their size and direction unchanged.

The pulley and the pulley

Roles are also often used in everyday life. In many elevators, for example, the motor lies on the ground. The force is then diverted via a roller at the top of the building and thus pulls the elevator upwards. However, the size of the force remains unchanged here as well.

The role shifts the point of application and the direction of a force and leaves its size unchanged.

However, several roles together can form a block and tackle, which can also change the amount of force. As can be seen in the following pictures, the force that is necessary to counteract the weight force, for example, can be reduced. The distance covered by the pulling force is greater, however, so that the work done is the same on both sides. The following applies exactly:

There is an equilibrium of forces on a pulley block with n pulleys when the force pulling on the rope is equal to the nth part of the force pulling on the loose pulleys.
F = FG / n

The lever

A means that is often used to increase force is the lever. It is understood to mean a rod rotatably mounted around a fixed axis. It is known from everyday life that the force is increased all the more with a longer lever arm. The torque is used to record this precisely. It is the product of a force on the lever arm that is perpendicular to it and the distance of the point of application of the force from the lever axis. Equilibrium, i.e. no acceleration, now exists when the sum of all torques rotating to the left is equal to the sum of all torques rotating to the right. If a torque predominates, the lever accelerates in this direction.

The lever is in equilibrium when the clockwise torque is the same as the counterclockwise torque.

The inclined or inclined plane

The principle of the inclined plane is known from ramps. We can roll a barrel up a ramp, but we cannot lift it the same height difference. So the force required on the inclined plane must be smaller. The following applies:

The forces on the inclined plane are in equilibrium when the tensile force is equal to the product of the weight of the load and the incline of the inclined plane.
F.Z = FG * h / l
F.Z = FG * sin α