a. The disk starts at rest, so its angular displacement at time is
It rotates 44.5 rad in this time, so we have
b. Since acceleration is constant, the average angular velocity is
where is the angular velocity achieved after 6.00 s. The velocity of the disk at time is
so we have
making the average velocity
Another way to find the average velocity is to compute it directly via
c. We already found this using the first method in part (b),
d. We already know
so this is just a matter of plugging in . We get
Or to make things slightly more interesting, we could have taken the end of the first 6.00 s interval to be the start of the next 6.00 s interval, so that
Then for we would get the same .
Answer:c
Explanation: because if you work it in a paper it should like lil wit is straight the numbers are going up by 16
Answer:
7.78x10^-8T
Explanation:
The Pointing Vector S is
S = (1/μ0) E × B
at any instant, where S, E, and B are vectors. Since E and B are always perpendicular in an EM wave,
S = (1/μ0) E B
where S, E and B are magnitudes. The average value of the Pointing Vector is
<S> = [1/(2 μ0)] E0 B0
where E0 and B0 are amplitudes. (This can be derived by finding the rms value of a sinusoidal wave over an integer number of wavelengths.)
Also at any instant,
E = c B
where E and B are magnitudes, so it must also be true at the instant of peak values
E0 = c B0
Substituting for E0,
<S> = [1/(2 μ0)] (c B0) B0 = [c/(2 μ0)] (B0)²
Solve for B0.
Bo = √ (0.724x2x4πx10^-7/ 3 x10^8)
= 7.79 x10 ^-8 T