Physics what is a period

This episode discusses: linear and angular velocity; degrees and radians; and angular acceleration. And is accompanied by Lesson Appears in these Collections Thinking About Teaching Collection Quantifying and using sound - Physics narrative A Physics Narrative presents a storyline, showing a coherent path through a topic Other resources on Period Period Forces and Motion.

Period Forces and Motion. Circular Motion Forces and Motion. A cycle is one complete oscillation. Note that a vibration can be a single or multiple event, whereas oscillations are usually repetitive for a significant number of cycles. We can use the formulas presented in this module to determine both the frequency based on known oscillations and the oscillation based on a known frequency.

Both Parts 1 and 2 can be answered using the relationship between period and frequency. In Part 1, the period T is given and we are asked to find frequency f.

In Part 2, the frequency f is given and we are asked to find the period T. The frequency of sound found in Part 1 is much higher than the highest frequency that humans can hear and, therefore, is called ultrasound. Appropriate oscillations at this frequency generate ultrasound used for noninvasive medical diagnoses, such as observations of a fetus in the womb.

Identify the known values:The time for one complete oscillation is the period T :. The period found in Part 2 is the time per cycle, but this value is often quoted as simply the time in convenient units ms or milliseconds in this case. Identify an event in your life such as receiving a paycheck that occurs regularly. Identify both the period and frequency of this event. I visit my parents for dinner every other Sunday. The frequency of my visits is 26 per calendar year. The period is two weeks.

Skip to main content. Oscillatory Motion and Waves. Search for:. Period is measured in time units appropriate for that system, but seconds are the most common. The second is a unit of time originally based on the rotation of the Earth on its axis and on its orbit around the sun, although the modern definition is based on vibrations of the cesium atom rather than on any astronomical phenomenon.

The periods of some systems are intuitive, such as the rotation of the Earth, which is a day, or by definition 86, seconds. You can calculate the periods of some other systems, such as an oscillating spring, by using characteristics of the system, such its as mass and spring constant.

When it comes to vibrations of light, things get a little more complicated, because photons move transversely through space while they vibrate, so wavelength is a more useful quantity than period.

For example, the Earth rotates once each day, so the period is 1 day, and the frequency is also 1 cycle per day. Period and frequency are reciprocal quantities:.

When considering rotating bodies in the macroscopic world, revolutions per minute rpm is also a common unit. Period can be measured in seconds, minutes or whatever time period is appropriate. The most basic type of periodic motion is that of a simple harmonic oscillator, which is defined as one which always experiences an acceleration proportional to its distance from the equilibrium position and directed toward the equilibrium position.

In the absence of frictional forces, both a pendulum and a mass attached to a spring can be simple harmonic oscillators. The minus sign indicates the force is always directed opposite the direction of displacement. The period of oscillation for a mass on a spring is then:. You can apply similar considerations to a simple pendulum, which is one on which all the mass is centered on the end of a string.