Q:A rectangular plate of sides a and b is supended from a ceiling by two parallel strings of length L each(Fig). The Separation between the strings is d. The plate is displaced slightly in its plane keeping the strings tight. Show that it will execute SHM. Find the time period http://www.freeimagehosting.net/newuploads/z8fe5.jpg Basic SHM equations: 1.F=-kx 2.T=(2*pi)/(omega) Let the plate be displaced a slightly for a displacement x and the angle of strings with vertical be theta. 2Tsin(theta)=-ma Using Approx. sin(theta)=x/L -2Tx/L=-ma I dont know how to eliminate T from the equation. Plz help!