HELP ASAP PLEASE A hopper train car is used for transporting grain. Empty it has a mass of about 28,000 kg. Fully loaded this mass increases to about 91,000 kg. Explain in terms of f=ma (Newton's Second Law) the difference in force needed to accelerate the two different train cars.

The intensity, or loudness, of a sound can be measured in decibels (db), according to the equation , where i is the intensity of a given sound and is the threshold of hearing intensity. what is the intensity, in decibels, [i(db)], when ? use a calculator. round to the nearest whole number. 8 9 19 80

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.

When a light bulb shines, it gives off light energy and energy. a. heat b. potential c. chemical d. electrical