To review relationships among electric potential, electric potential energy, and force on a test charge
This problem is a review of the relationship between an electric field E? , its associated electric potential V, the electric potential energy U, and the direction of force on a test charge.
Part A
Electric field lines always begin at charges (or at infinity) and end at charges (or at infinity). One could also say that the lines we use to represent an electric field indicate the direction in which a test charge would initially move when released from rest. Which of the following fills in the three missing words correctly?
(positive; negative; negative)__
(positive; negative; positive)__
(negative; positive; negative)__
(negative; positive; positive)__

Which type of microscope would allow the viewer to see ribosomes inside a cell?

The inside surface of a cylindrical-shaped cave of inner diameter 1.0 m is continuously covered with a very thin layer of water. the cave is very long and it is open on both ends. the water on the cave surface is at a constant temperature of 15.5 °c. the cave is constantly exposed to wind such that 15.5 °c air flows through the cave at 4.5 m/s. the kinematic viscosity of the air is 14.66 x 10-6 m2/s and the molecular diffusion coefficient of water vapor in the air is 0.239 x 10-4 m2/s. because the cave diameter is so large, the flow of wind down the length of the cave, in the x direction, can be treated like it is external flow and the cave surface can be approximated as flat where appropriate. calculate the x value, in a) the transition to turbulent flow occurs at rex meters, where the air flow transitions from laminar to turbulent along the inside surface of the cave b) calculate the x value, in meters, where the bulk steady state concentration of water vapor in the air flowing in the cave is 10% of the saturation concentration. assume the air at the surface of the water layer is 100% saturated with water vapor. assume the wind entering the cave contained no moisture before it entered the cave. take into account the transition from laminar to turbulent flow when solving part b

Four friends, a, b, c, and d are standing varying distances away from a speaker which is producing sound waves.