Answer:

Explanation:
The circular movement is produced by the magnetic field:

This force is a centripetal force because the electron moves in a plane perpendicular to the magnetic field. For a centripetal Force, that produces a circular orbit with a radius r:

If we solve these two equations in order to find r, with the mass and charge of a electron:

Answer:
A. you would want to use the 12 ound ball and the 18 mph speed in order to transfer the most kinetic energy
B. KE= 1/2 MV^2 so you would want to maximize both your Mass(weight of the ball) and Velocity(speed of the roll) in order to achive the greatest KE.
C. see image
Explanation:
Full disclosure not totally sure what you are being asked in the last one but I put togethere a rough sketch that is my best guess.
C, N and O all belong to the same period, in which it's 2nd Period.
PRE stands for progressive resistance exercises. This refers to exercises which progressively increase the load applied to the muscles. Here are some guidelines for safe PRE:
1. Do the exercises slowly, surely and smoothly. Avoid doing abrupt movements so as not to strain your muscles.
2. When doing the exercises, make your you execute them properly. For example, when lifting weights, lift them all the way up and all the way down.
3. Use spotters for support and to avoid accidents.