Astudent wants to vary the force of repulsion between two magnets. which method could the student use?
a.
face opposite poles of the magnets toward one another, and vary their distance.
b.
face the same poles of the magnets toward one another, and vary their distance.
c.
face the same poles of the magnets toward one another, and vary their temperature.
d.
face opposite poles of the magnets toward one another, and vary their temperature.

Avertical clean glass piezometer tube has an inside diameter of d = 1 mm and is used to measure pressure in a horizontal pipe carrying water as shown. due to pressure in the pipe, the water at 20c rises into the tube to a height h. if the water pressure in the pipe is p = 500 pa gauge, estimate the height h: (a) without considering surface tension (b) with surface tension (capillary) effects. the contact angle  can be assumed at 30 deg