# What is an introduction to circular motion

## Introduction of uniform circular movements

Introduction of uniform circular movements Here you should work out important parameters for describing uniform circular movements. Let's do the whole thing from the following point of view: Our goal: "How much can the human body withstand and which forces act on it in a centrifuge?" Jet pilots and astronauts have to train in centrifuges before they actually start. If the people are not yet adequately trained, blackouts in the centrifuge occur. The video at the top left shows how much g is acting on the pilot. 2g means twice the acceleration due to gravity.
﻿Basic terms for circular movements In order to study circular motions, we need some basic concepts. 1) Period duration (cycle time) T The period duration describes somewhat casually "how much time you need for a certain number of revolutions". Or as a formula: 2) frequency f The frequency turns the whole thing around and is loosely formulated "How many revolutions can I manage per time". Or as a formula. The unit of frequency is the Hertz (abbreviated as Hz). Remember: In physics, the second is the basic unit (SI unit) of time.
﻿Task 1 (upload to itsLearning) a) The Ferris wheel in the picture below rotates 2 times in 4.5 minutes. Give the period T and the frequency of this circular motion. b) Express the unit Hz using the unit second. c) Which physical unit does the period have?
﻿3) The radian measure (RAD in the GTR) In the natural sciences, all angles in calculations are only used in the so-called. Radians specified. This means that from now on, details such as 10 ° are unfortunately taboo. The following formulas are used for conversion. We also need the radian measure below to define the so-called path speed. If you don't define it with the help of radians, the result is a unit that is difficult to interpret.
Task 2 (upload to itsLearning) a) Convert the following angles in degrees into the corresponding angles in radians: 180 °, 30 °, 360 °, 90 ° b) Convert the following angles in radians into degrees: and

### Optional: Take a look at the derivation of the formula from simpleclub

Two types of speed With uniform circular movements, 2 different speeds can be observed, which we will now look at using a helicopter.

### Model of a rotor (a rotor blade)

Task 3 (upload to itsLearning) Start the simulation and answer the following questions a) Justify which of the two points on the rotor blade covers a longer distance in a certain time. What does the distance covered depend on? b) Explain which of the two points on the rotor blade covers the larger angle (green in the simulation) within a certain time. What does the swept angle (only) depend on?
Now slowly ...In Exercise 3 we looked at two sizes: once the angle and once the distance of a point on a circular path. And both always for some time. So if you divide "angle through time" or "path on the circular path through time" you get a kind of speed, which we now look at: 1) The angular velocity The angular velocity (pronunciation: omega) of a point on a circular path describes "How many angles (in radians) I cover in a certain time". As a formula. The whole thing is similar to the formula for the speed only that the angle is now in the numerator. The angular velocity can be like this to calculate: where is the frequency. 2) The path speed The path speed describes the distance (in meters) a point covers on a circular path per time. As a formula:, the letter describes the distance of the point from the center of the circle. Alternatively, the path speed can also be specified with the aid of the frequency, where:. The formulas are not derived here.
﻿Task 4 (upload to itsLearning) The rotor of a wind turbine rotates around itself 5 times in one minute. The radius (i.e. the length of a rotor blade from the center of the circle) is 63m. a) Calculate the frequency of the circular motion. b) Calculate the angular velocity of a point on the rotor blades. c) Calculate the orbital speed of a point at the end of the rotor blades and a point that is away from the center of the circle.