A landscaping company uses 3 1/2 tons of rock in the first month. In the second month, the company uses the same amount of rock in each of its 5 projects. The company uses 7 1/4 tons of rock over the two months. How many tons of rock does the landscaping company use in each project in the second month?

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).