A mass of 0.39 kg connected to a light spring with a spring constant of 22.2 N/m oscillates on a frictionless horizontal surface. If the spring is compressed 4.0 cm and released from rest, determine the following. (a) the maximum speed of the mass (b) the speed of the mass when the spring is compressed 1.5 cm (c) the speed of the mass when the spring is stretched 1.5 cm (d) For what value of x does the speed equal one-half the maximum speed? When four people with a combined mass of 280 kg sit down in a car, they find that the car drops 1.00 cm lower on its springs. Then they get out of the car and bounce it up and down. What is the frequency of the car's vibration if its mass (empty) is 2.0 x 10^3 kg? I don't even know where to start on these, so all I'm asking for is a nudge in the right direction, possibly some formulas or reading material.