Work is being done in which of these situations? all motions are at a constant velocity (including velocity = zero).
a. jessica pushes a 25 kilogram cart a distance of 10 meters.
b. bane carries a 20 kilogram box a distance of 50 meters.
c.
a weightlifter holds a 100 kilogram barbell over his head.
d.
all is trying to push a truck away from the parking lot.
e.
yana carries a 5 kilogram bag a distance of 1 kilometer.
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Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.