W=F*d
W=-60N*5m=-300J
So friction does -300J of work on the box
Answer:
a. E = 
b. 
Explanation:
The important thing to remember is to use Gauss Law. This is a relation that describes the distribution of electric charge to the resultant electric field.
Linear charge density means charge per unit length of material.
Data:
The metal cylinder is hollow.
The unit length is L.
a.The expression will be as follows:
for charge inside the cylinder, where r < R, the expression is:
E = 
b. Let's assume that the cylinder is a coaxial cylinder with a radius r > R, then the electrical field strength is given as:

E = 
E = 
This gives:

The solution informs us that there is a surface change taking place on the cylinder. Therefore, there will not be a magnetic field across it.
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