work done on particles in electric field

[sacha]

Y,Z & W are all positively charged, Y & Z move a horizontal distance of 2m against the electric field while W moves a horizontal distance of 2m in the opposite direction.

Qu: Same amount of work is done by?
Ans: Y & Z only

doesn't W do the same amount of work since it moves the same distance? (formula given in answer key: work done = voltage drop x q = Ed)

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[ilovemcat]

Y,Z & W are all positively charged, Y & Z move a horizontal distance of 2m against the electric field while W moves a horizontal distance of 2m in the opposite direction.

Qu: Same amount of work is done by?
Ans: Y & Z only

doesn't W do the same amount of work since it moves the same distance? (formula given in answer key: work done = voltage drop x q = Ed)

Positive Work is being done ON particles Y and Z. Work is done BY particle W. Notice the direction of the E-field. Y and Z are moving towards a positive source (gaining potential energy), while W is moving in the direction it wants to (losing potential energy). Therefore, because the sign of work is different, the work isn't the "same." Now, if they said "same magnitude," then all 3 answers would be correct.