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Science question I have

So hertz is 1/s. Speed has unit of m/s. So can I make the substitution and say speed has unit of m*Hz?

February 12, 2014

16 Comments • Newest first

LampShadow

[quote=Bob11111]@LampShadow: They just said Hertz is for waves. My concern is not that. I only wish to know if my substitution is correct.[/quote]

It's not, please refer to my previous post:

[quote=LampShadow]Hertz is measured in cycles/second. Cycles are considered unit-less units in physics, but they can't just be ignored during calculations. An object/particle/wave can have both a velocity and frequency at the same time, and they can be completely different[/quote]

An object can rotate around a center with a velocity of 3 m/s, and still have a frequency of 1Hz to 100Hz depending on the radius of its path.

Hertz is the unit for frequency, and frequency is defined as "the number of occurrences of a repeating event per unit time". These occurrences are unit-less, but still must be considered in calculation

Reply February 12, 2014
MagicDate

[quote=Bob11111]@LampShadow: They just said Hertz is for waves. My concern is not that. I only wish to know if my substitution is correct.[/quote]

All I'm seeing from you is that you want to get someone to agree with you, and refute anyone who doesn't.

Reply February 12, 2014
NoobCake

[quote=Bob11111]@LampShadow: They just said Hertz is for waves. My concern is not that. I only wish to know if my substitution is correct.[/quote]

It's an incorrect measurement, I don't know how much clearer I can be about that. For example, lb*ft (torque) is not the same as ft*lb (energy) although you would assume so due to mathematical operation laws.

Reply February 12, 2014
Bob11111

@LampShadow: They just said Hertz is for waves. My concern is not that. I only wish to know if my substitution is correct.

Reply February 12, 2014
LampShadow

[quote=Bob11111]@NoobCake: m/s has s^-1 in it. s^-1 = Hz. So why can't I do m/s = m * Hz?[/quote]

Have you even looked at the other responses in the thread? It's already been explained

Reply February 12, 2014
Bob11111

@NoobCake: m/s has s^-1 in it. s^-1 = Hz. So why can't I do m/s = m * Hz?

Reply February 12, 2014
Bob11111

[quote=NoobCake]Same reason why we don't say "this book has a mass of 400mL". Although 1mL=1g, it's more correct to say the book has a mass of 400g.[/quote]

No, 1 mL != 1g. That is only true for water. Volume and mass are different.

Reply February 12, 2014
NoobCake

[quote=Bob11111]I completely understand that I will sound stupid saying meter hertz. But I don't see why you say meter hertz is an incorrect unit.[/quote]

Same reason why we don't say "this book has a mass of 400mL". Although 1mL=1g, it's more correct to say the book has a mass of 400g.

Reply February 12, 2014
Meergl

Hertz is a frequency. X Hz means something happens X times per second. As NoobCake said, most often it's used in the context of wave oscillations. You can also use it for say, jumping or snapping your fingers or whatever. However, you can't do something meter times per second.

Reply February 12, 2014
LampShadow

It's pretty much what @ox0Shad0w0xo said. Hertz is measured in cycles/second. Cycles are considered unit-less units in physics, but they can't just be ignored during calculations. An object/particle/wave can have both a velocity and frequency at the same time, and they can be completely different

Reply February 12, 2014
Bob11111

[quote=NoobCake]Technically yes but you'll sound stupid since Hertz mainly refers to frequency of waves. Unless you're a wave, you're not "walking at 2 meter hertz" (and even this unit of measurement is incorrect). However, you are modeled as a particle so saying "I walk at 2 meter per second" is more correct.[/quote]

I completely understand that I will sound stupid saying meter hertz. But I don't see why you say meter hertz is an incorrect unit.

Reply February 12, 2014
NoobCake

[quote=Bob11111]Hertz is s^-1. Speed is measured in m * s^-1. I'm just substituting and getting m * Hz. Like can you say I walk at 2 meter hertz instead of meter per second?[/quote]

Technically yes but you'll sound stupid since Hertz mainly refers to frequency of waves. Unless you're a wave, you're not "walking at 2 meter hertz" (and even this unit of measurement is incorrect). However, you are modeled as a particle so saying "I walk at 2 meter per second" is more correct.

Reply February 12, 2014 - edited
Bob11111

[quote=ox0Shad0w0xo]Hertz is the measure of cycles per second. So it's saying 1 cycle per second. And it's usually used to measure electronic and sound waves.

While speed is the magnitude of an objects velocity. So it's the distance traveled divided by the duration of the interval (time, in this case being 1 second). Why are you trying to combine the two? Sure you can use m/s to describe the speed of a sound wave, but generally you don't use hertz [i]and[/i] velocity at the same time. So I'm not really sure what you're trying to calculate.[/quote]

Hertz is s^-1. Speed is measured in m * s^-1. I'm just substituting and getting m * Hz. Like can you say I walk at 2 meter hertz instead of meter per second?

Reply February 12, 2014 - edited
ox0Shad0w0xo

Hertz is the measure of cycles per second. So it's saying 1 cycle per second. And it's usually used to measure electronic and sound waves.

While speed is the magnitude of an objects velocity. So it's the distance traveled divided by the duration of the interval (time, in this case being 1 second). Why are you trying to combine the two? Sure you can use m/s to describe the speed of a sound wave, but generally you don't use hertz [i]and[/i] velocity at the same time. So I'm not really sure what you're trying to calculate.

Reply February 12, 2014 - edited