Electromagnetic waves don't require a medium to travel.
Answer:
no
actually no one weres the scarf in sunny ʕ•ε•ʔ
Explanation:
The colours we see are the wavelengths that are reflected or transmitted. For example, a red shirt looks red because the dye molecules in the fabric have absorbed the wavelengths of light from
Light travels at the speed of 186,000 miles per second. If you were to travel around the earth it would be 7.5 times in a second
Answer:
Simple machine: pair of tongs, seesaw and wheelbarrow
Compound machine: sewing machine, fishing rod and reel and crane.
Explanation:
Simple machine is the simplest device to use mechanical advantages. It has simplest mechanism to multiply the magnitude of force.
So, pair of tongs, seesaw and wheelbarrow are the example of simple machine because their mechanism is simplest.
Compound machine is a device that is made up of more than one simple machine.
so, sewing machine, fishing rod and reel and crane are example of compound machine because these devices shows more than one machine in it.
Thus, classification is as follows:
Simple machine: pair of tongs, seesaw and wheelbarrow
Compound machine: sewing machine, fishing rod and reel and crane.
Explanation:
For this problem we have to take into account the expression
J = I/area = I/(π*r^(2))
By taking I we have
I = π*r^(2)*J
(a)
For Ja = J0r/R the current is not constant in the wire. Hence

and on the surface the current is

(b)
For Jb = J0(1 - r/R)

and on the surface

(c)
Ja maximizes the current density near the wire's surface
Additional point
The total current in the wire is obtained by integrating

and in a simmilar way for Jb
![I_{T}=\pi J_{0} \int\limits^R_0 {r^{2}(1-r/R)} \, dr = \pi J_{0}[\frac{R^{3}}{3}-\frac{R^{2}}{2R}]=\pi J_{0}[\frac{R^{3}}{3}-\frac{R^{2}}{2}]](https://tex.z-dn.net/?f=I_%7BT%7D%3D%5Cpi%20J_%7B0%7D%20%5Cint%5Climits%5ER_0%20%7Br%5E%7B2%7D%281-r%2FR%29%7D%20%5C%2C%20dr%20%3D%20%5Cpi%20%20%20J_%7B0%7D%5B%5Cfrac%7BR%5E%7B3%7D%7D%7B3%7D-%5Cfrac%7BR%5E%7B2%7D%7D%7B2R%7D%5D%3D%5Cpi%20J_%7B0%7D%5B%5Cfrac%7BR%5E%7B3%7D%7D%7B3%7D-%5Cfrac%7BR%5E%7B2%7D%7D%7B2%7D%5D)
And it is only necessary to replace J0 and R.
I hope this is useful for you
regards