Relationships Between Force, Field, Energy, Potential Video Lessons

Concept

# Problem: A negative charge (q=-0.55 coulombs) is placed above the floor that has a positive charge. The floor creates a uniform electric field that has a magnitude of 105 N/C.a) What is the magnitude and direction of the electric force caused by the floor on the negative charge?b) If the charge is initially at a distance 2.5m above the plane, what will the change in electric potential energy (in joules) be if it is then moved to a distance 1.25m above the plane? (specify whether this change is positive/negative/zero).

###### FREE Expert Solution

Electric force:

$\overline{){\mathbf{F}}{\mathbf{=}}{\mathbf{qE}}}$

Potential:

$\overline{){\mathbf{V}}{\mathbf{=}}{\mathbf{E}}{\mathbf{·}}{\mathbf{d}}}$

(a)

F = qE = (0.55)(105) =  57.8 N

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###### Problem Details

A negative charge (q=-0.55 coulombs) is placed above the floor that has a positive charge. The floor creates a uniform electric field that has a magnitude of 105 N/C.

a) What is the magnitude and direction of the electric force caused by the floor on the negative charge?

b) If the charge is initially at a distance 2.5m above the plane, what will the change in electric potential energy (in joules) be if it is then moved to a distance 1.25m above the plane? (specify whether this change is positive/negative/zero).