Astack of 60 identical books at the book store was 135 inches tall.

how thick was each book?

a.
2.25 inches

b.
6.75 inches

c.
7.5 inches

d.
22.5 inches
i need instantly

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).