Why a reference point must be stationary?

Agas is contained in a vertical, frictionless piston–cylinder device. the piston has a mass of 3.2 kg and a cross-sectional area of 35 cm2. a compressed spring above the piston exerts a force of 190 n on the piston. if the atmospheric pressure is 95 kpa, determine the pressure inside the cylinder.

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

Which of the following is the best name for mgcl2