-->

Units And Measurement

Question
CBSEENPH11016541

Given y = a sin (ωt– kx) where 'x' is position and 't' is time. Show that ω/k has dimensions of velocity.

Solution
Here, y = a sin (ωt- kx), where x is position and t is time. 
Sine has dimensions of angle, which is dimensionless.
therefore ωt is dimensionless. 
And straight omega has the same dimensional formula as that of frequency. 
So, straight omega space equals space open parentheses straight M to the power of 0 straight L to the power of 0 straight T to the power of negative 1 end exponent close parentheses
Similarly, kx is dimensionless and dimensions of k are,               k italic space italic equals italic space open square brackets M to the power of italic 0 L to the power of italic minus italic 1 end exponent T to the power of italic 0 close square brackets
Now dimensional formula of, 
straight omega over straight k equals fraction numerator open square brackets straight M to the power of 0 straight L to the power of 0 straight T to the power of negative 1 end exponent close square brackets over denominator open square brackets straight M to the power of 0 straight L to the power of negative 1 end exponent straight T to the power of 0 close square brackets end fraction equals open square brackets straight M to the power of 0 straight L to the power of 1 straight T to the power of negative 1 end exponent close square brackets , which is same as the dimensions of velocity.