11. In an experiment to determine the size of an oil molecule, clean water was placed in a large basin and then left over several minutes without any disturbance. Lycopodium powder was carefully
spread on the water surface. A drop of oil was then taken from a container using a fine wire. its
diameter was measured using a millimeter scale with the aid of a hand lens and was found to be
0.35mm. The oil drop was carefully transferred onto the water surface where it spread to form a
circular patch of diameter 14cm.
(a)Use the measurements obtained to determine:
(1)The approximate volume of an oil molecule in mm³​

Aperson walks first at a constant speed of 4.89 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.95 m/s. what is the average speed over the entire trip?

The energy equivalent of the rest mass of an electron is

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.