First of all, let's just talk about the speed, and not get wound up
in the velocity. OK ?
If a fly is sitting on the rim of the wheel and the wheel is rotating, then for
each full revolution of the wheel, the fly travels the circumference of the
wheel, which is (2 π) x (radius of the wheel).
In 'N' revolutions, the fly travels (2 N π) x (the radius). and so on.
So if the wheel is going, let's say 71 revs per minute (RPM), a point
on the rim is moving at (2 π times 71) x (the radius) per minute.
Another way to say it:
Speed of a point on the circle = (2 π) x (rotation frequency) x (radius).
The 'rotation frequency' takes care of the unit of time, and the 'radius'
takes care of the unit of length, so the result is a speed.
It starts or speeds up.
Some substances need certain amount of energy in order to react with each other.
Answer:
C. a disturbance that travels through a medium with a transfer of energy and without a transfer of matter
Explanation:
A wave is any disturbance that transfers energy from one location to the other via a substance called medium. It is important to note that a wave only conveys energy and not matter. For example, sound wave is a type of wave that carries sound energy from one place to another via mediums such as water, air etc.
Hence, according to this question, a wave can be described as a disturbance that travels through a medium with a transfer of energy and WITHOUT A TRANSFER OF MATTER.
Answer:
Explanation:
The amplitude of resultant wave as the result of overlap of two waves depends upon the phase difference between the two. If the waves meet crest to trough , the phase difference is 180 degree or they are in opposite phase . Hence they will destroy each other . The amplitude of resultant wave can be obtained by subtracting the amplitudes of two waves. They will interfere destructively.
Amplitude of resultant gives waves = 4.6 - 2 = 2.6 cm.
I believe your answer should be C. Speed.
