1) A 4kg mass rests on a tabletop and is attached to a spring with the spring constant 100N/m. The other end of the spring is clamped to the table such that the spring is in horizontal position. A 6.0 kg mass is placed on top of the 4 kg mass. What should be the minimum value of the coefficient of the static friction between the two masses, if an oscillation, whose maximum velocity is 4.0m/s keeps the 6.0 kg mass on top of the 4.0 kg mass?
2) Given the above velocity, find the equation of motion for the oscillator.