Answer:
90 ohms
Explanation:
1/r = 1/180 + 1/180
1/r= 2/180
take the reciprocal of 2/180 which is 180/2 and its 90 ohms
Answer:
Motors commonly contain a "commutator" which allows a magnetic field due to a loop of wire to always be in a say "clockwise or counterclockwise" direction even tho the loop of wire is rotating.
That means that magnetic field due to the surrounding magnets is always in the same direction, but the magnetic field due to the rotating loop of wire is continually changing so that it will always oppose the surrounding field which remains in a constant direction.
This is most easily seen in a "DC - direct current motor".
(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.
Recall that
We have 
, so that
(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.
(c) The ball's average velocity is 0. Average velocity is given by 
, and we know that .
(d) The position of the ball 
at time 
is given by
Take the starting position to be the origin, 
. Then after 6 seconds,
so the ball is 42 m away from where it started.
We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:
Since the velocity is positive, the ball is still moving up the incline.
<span>C is the correct answer. Electron microscopes require a vacuum to work, so living cells cannot be seen because they cannot respire. Light microscopes use a ray of visible light instead of a beam of electrons to magnify something so it can be seen by the naked eye. There are two different types of electron microscope: transmission (TEM) and scanning (SEM).</span>
The answer is near the poles.
