How often does the moon go through an entire set of phases

Two red blood cells each have a mass of 9.0 multiply.gif 10-14 kg and carry a negative charge spread uniformly over their surfaces. the repulsion arising from the excess charge prevents the cells from clumping together. one cell carries −2.50 pc of charge and the other −3.10 pc, and each cell can be modeled as a sphere 7.5 μm in diameter. (a) what speed would they need when very far away from each other to get close enough to just touch? assume that there is no viscous drag from any of the surrounding liquid. answer is: 321 m/s how do i find this (b) what is the maximum acceleration of the cells in part (a)? answer is: 1.38e+10 m/s2 how did they find this answer

When conducting an investigation to determine which type of fertilizer produces the most flowers on a plant, which variable would be graphed on the x-axis once you collected the data? a. type of fertilizer b. amount of flowers c. amount of water d. number of days that the plants grew

You are doing a science experiment with a fahrenheit thermometer. your data must be in degrees celsius. if you measure a temperature of 125°f, what is this temperature in degrees celsius