A positive charge cause dosent your hair static up when that happens or no?
Well I don't know. Let's actually LOOK at the picture and see if that helps.
A, B, C, and D all have the same TOTAL length, but A has the most waves crammed into that same total length.
By golly, that means the length of <u><em>each</em></u> wave in A must be shorter than each wave in B, C, or D.
The correct choice is <em> A </em>. Looking at the picture did the trick !
Answer: 2940 J
Explanation: solution attached:
PE= mgh
Substitute the values:
PE= 10kg x 9.8 m/s² x 30 m
= 2940 J
Yes because of the smoke you are creating in the air
Answer:

Explanation:
c = Speed of wave
= Density of medium
A = Area
= Frequency

Intensity of sound is given by

So,

We get

The ratio is 