Which of the following changes will result in a weaker electromagnet. a. using a longer wire b. using fewer coil of wire c. using a higher voltage d. using a shorter nail

Amass weighing 24 pounds, attached to the end of a spring, stretches it 4 inches. initially, the mass is released from rest from a point 8 inches below the equilibrium position. find the equation of motion. (use g = 32 ft/s2 for the acceleration due to gravity.)