Homework Statement
A balloon is rising at a constant speed of 5ft/s. A boy cycling along a straight road at a speed of 15 ft/s. When he passes directly under the balloon, it is 45 ft above him. how fast is the distance between the boy and the balloon increasing 3 seconds later?
Homework...
Homework Statement
A long metal cylinder with radius a is held on the axis of a long, hollow, metal tube with radius b. The inner cylinder has positive charge per unit length \lambda, and the outer cylinder has an equal negative charge per unit length. Calculate the potential V(r) for r<a...
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Sorry for the bad picture, but suppose there's a uniform rod of charge has a length L and a net charge +Q, find the force that this rod exert on a point charge q placed at (0,y).
Ok, I...