It stands for Unified Computing System
I hope I helped :3
I uploaded the answer to a file hosting. Here's link:
tinyurl.com/wpazsebu
Answer:
Yes option A is right.
Explanation:
As we know that the "Opposite charges attract and like charges repel eachother". So based upon that fact we find out the sphere will be repelled or attract by the rod. As in this case metallic sphere was neutral initially but then we touched the rod with it. Although it was for few seconds but the charge is transferred to the sphere. Now both sphere and the rod have charge. After the seperation we look towards their respond If both have the opposite charge they will attract eachother. But here in this case they repel because they have the same charge, as we have charged the neutral sphere with the rod so we already know that they have the same charges that is why they are repelling eachother.
Insulation from the ground means that blocking the way of charges or free electrons from earth to metallic sphere and vice versa. As there exists free electrons and charges in earth they would flow into the metallic objects. So for more precise and accurate experiments we insulate the metals or prevent the metals from touching the earth surface to avoid the flow of charges through them. I hope it will help you.
Health and safety are two reasons
The concept to solve this problem is related to the relativistic physics for which the speed of the object in different frames of reference is related. This concept is called Velocity-addition formula
and can be written as,

Where,
u = Velocity of a body within a Lorentz Frame
v = Velocity of a second frame
u'= The transformed velocity of the body within the second frame
c = speed of light
Replacing we have to




Therefore the meteor moving with respect to the Earth to 230'700.000m/s