Answer:
Image B represents the force on a positively charged particle caused by an approaching magnet.
Explanation:
The most fundamental law of magnetism is that like shafts repulse each other and dissimilar to posts pull in one another; this can without much of a stretch be seen by endeavoring to put like posts of two magnets together. Further attractive impacts additionally exist. On the off chance that a bar magnet is cut into two pieces, the pieces become singular magnets with inverse shafts. Also, pounding, warming or winding of the magnets can demagnetize them, on the grounds that such dealing with separates the direct game plan of the particles. A last law of magnetism alludes to maintenance; a long bar magnet will hold its magnetism longer than a short bar magnet. The domain theory of magnetism expresses that every single enormous magnet involve littler attractive districts, or domains. The attractive character of domains originates from the nearness of significantly littler units, called dipoles. Iotas are masterminded in such a manner in many materials that the attractive direction of one electron counteracts the direction of another; in any case, ferromagnetic substances, for example, iron are unique. The nuclear cosmetics of these substances is with the end goal that littler gatherings of particles unite as one into zones called domains; in these, all the electrons have the equivalent attractive direction.
One of the efficient concepts that can help us find the number of turns of the cable is through the concept of induced voltage or electromotive force given by Faraday's law. The electromotive force or emf can be described as,

Where,
N = Number of loops
B = Magnetic Field
A = Cross-sectional Area
= Angular velocity
Re-arrange to find N,

Our values are given as,




Replacing at our equation we have:



Therefore the number of loops of wire should be wound on the square armature is 32 loops
Answer:
1 joule = 0.737 foot-pound
Joule is the unit of work.
1 J = 1 N·m
In SI units
1 J = 1 kg· m/s²
0.737 foot-pound is the amount of work to raise 0.737 pounds one foot or raising one pound to 0.737 ft.
When a body strictly moves on a curve, it's velocity at a point is tangential to the curve at that point.
Centripetal acceleration is the acceleration that a body experiences by the virtue of change in it's tangential velocity. It is directed towards the centre and mathematically is v^2/R where v is the speed at the instant.
So, 18 = v^2/R
v^2 = 504
v = 6√14
The motorist travels (a) 58 km/h and (b) ~16.1 m/sec