This is just a simple problem finding out the outer surface charge, the inner surface charge and the net charge. Net charge by definition means the difference between two charges. In this case, the formula that is applicable here is outer surface charge = total net charge - inner cavity surface charge. Since we are given already with the net charge equal to 12.0 x10-6 C and the inner charge magnituude f 3.7 x10-6 C, the the total charge must be outer charge is +10x10(-6)) - (-3.0x10(-6)) = +1.3x10(-5) C.
Charges are measured in coloumbs and most likely exist on surfaces of entities like particles, walls etc.
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Your answer would be the; <u>NET</u> force on the object. Refer to Newton's Laws of Forces and Motion.
Hope that helps!!!!!!!!!!!!!!!! : )
Answer:

Explanation:
Let hockey puck is moving at constant speed v
so here we have

so time taken by the puck to strike the wall is given as

now time taken by sound to come back at the position of shooter is given as


so we know that total time is 1.9 s




now we have


In Rutherford's gold foil experiment, some of the positive particles would pass through the foil and some would bounce off. This led to a new theory that all of the positive subatomic particles were in the center of the atom instead of evenly spread throughout.