What is the threshold velocity vthreshold(water) (i. e., the minimum velocity) for creating Cherenkov light from a charged particle as it travels through water (which has an index of refraction of n=1.33)?

Atriangle with equal sides of length 10 cm has -2.5-nc charged objects at each corner. part a determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. horizontally rightward vertically downward vertically upward horizontally leftward