The planet xyz traveling about the star abc in a circular orbit takes 24 hours to make an orbit. assume that the orbit is a circle with radius 89 comma 000 comma 00089,000,000 mi. find the linear speed of xyz in miles per hour.

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

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.