Answer:
C. 0 J
Explanation:
When an object moves in a circle, friction provides the centripetal force. Hence, it is acting towards the centre of the circle. The displacement of the object is tangential to the circle at the point of interest. Hence, the angle between the frictional force and the displacement is 90°.
Work done is given by
<em>W</em> = <em>Fd</em> cos <em>θ</em>
where <em>F</em> is the force, <em>d</em> is the displacement and <em>θ</em> is the angle between them.
<em>W</em> = <em>Fd</em> cos 90° = 0 J
Hence, the work done by friction is 0 J.
Please check the attached picture
When two sound waves of similar frequency interfere with each other, there is a fluctuating sound heard which is periodic and repeating. This fluctuating sound is called beat. Beat frequency( number of beats per second) is equal to the difference of the frequency of the two sound waves.
So, sound waves of frequency 400 Hz and 404 Hz will produce 4 beats per second.
1/s' = 1/f - 1/s
= 1/12 - 1/8
= 2/24 - 3/24
= 2-3/24
= - 1/24
s'= -24
M= |s'/s|
M = |24/8|
M = 3
