Question

Which two factors are needed in order to calculate the speed of a wave?
A. frequency and wavelength
B. amplitude and period
C. amplitude and frequency
D. energy and period

Answer 1

Ok... this one is hard to explain without just giving you the answer. But I'll try. Tell me about any formulas that you can remember.

Answer 2

For example, you remember that period = 1/frequency from our previous example. This one doesn't appear in our choices, unfortunately, but you'd know that this one doesn't apply. Do you know of any that do apply?

Answer 3

I'd think that frequency has to apply right?

Answer 4

Gah.... I can't figure out how to give an explanation for this one without blatantly giving the answer. I feel hypocrital for doing this, but... here's a speed function:

Speed = wavelength / period. T_T

Answer 5

?

Answer 6

doesnt seem to be an option ahha

Answer 7

i kinda gave you the answer if you can link the hints together. ;)

Answer 8

Look a little bit higher at my earlier post about period = blah blah. ;)

Answer 9

AGHHHHHHH But I'm sooooooooo tired >:(

Answer 10

Do you remember earlier that we said
Period = 1/frequency ?

Answer 11

And you know from my formula that speed = wavelength / period

Answer 12

mhm...

Answer 13

Using period = 1/frequency, would you be able to tell me what the period is if I only gave you a frequency?

Answer 14

yea...so its...

Answer 15

Perfect! So keep this in mind: anytime you have frequency, you know what the period is. Anytime you have period, you know what the frequency is, right?

Answer 16

(just agree with me, and I'll show you why this was important)

Answer 17

haha right

Answer 18

rewrite Speed = wavelength/(period) so that period is *legitimately* replaced with frequency.

In other words, I'm not asking you to literally replace it as speed = wavelength/frequency. But using the other formula, you CAN replace period with something else that contains frequency.

Answer 19

in other words, if you see "period", you can replace it with (1/frequency), right? Thanks to the equation, period = 1/frequency, right?

Answer 20

ohhhhh so then A!!!!!!!!

Answer 21

?

Answer 22

YUP :D

Now just tell me what the equation would be if you were to make an equation using only speed, wavelength and frequency.

Answer 23

hahaha
what do you mean?

Answer 24

Well, we know the original equation used speed, wavelength and period in this form:

speed = wavelength/period

I want you to rewrite that equation so it includes frequency instead of period.

Answer 25

But to where it's still true. In other words,
speed = wavelength/frequency is NOT the right answer, because frequency does not = period

Answer 26

So...Period = wavelength/frequency? just taking a guess..

Answer 27

I'm afraid not.
Remember there are two separate formulas we worked with:
1) period = 1/frequency
2) speed = wavelength/period

So far so good?

Answer 28

mhm :)

Answer 29

Alright, so the first equation is saying that 'anytime you see period, you can replace it with......... what?

Answer 30

In other words, period = what?

Answer 31

frequency = wavelength / speed?

Answer 32

ohhhhhhhhhh ahahahaha

Answer 33

frequency

Answer 34

Close.

Answer 35

it doesn't say period = frequency

Answer 36

oh...right.

Answer 37

period = \[\frac{1}{frequency}\]

speed = \[\frac{wavelength}{period}\]

Maybe my formulas were just messy. Does it make more sense now?

Answer 38

Make believe the fractions weren't under the equals... should have been NEXT to the equals.

Answer 39

OHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 40

So, if we see period, what can we replace it with? :P Or... what does period =, according to the "period =" equation?