The distance to a particular star, as measured in the earth’s frame of reference, is 7.74 ly (1 light year is the distance light travels in 1 year). A spaceship leaves earth headed for the star, and takes 3.49 yr to arrive, as measured by passengers on the ship. Part A) How long does the trip take, according to observers on earth? Express your answer with the appropriate units. t = yrPart B) What distance for the trip do passengers on the spacecraft measure?

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.