Apassenger railroad car has a total of 8 wheels. springs on each wheel compress--slightly--when the car is loaded. ratings for the car give stiffness per wheel (the spring constant, treating the entire spring assembly as a single spring) as 2.8×10⁷n/m.
when 30 passengers, each with average mass of 80 kg, board the car, how much does the car move down on its spring suspension? assume that each wheel supports 1/8 the weight of the car.