Science subject. where is the earths crust the thickest below the continents ? beneath the oceans ? below the equator ? or below the north pole ?

Part of a control linkage for an airplane consists of a rigid member cb and a flexible cable ab. if a force is applied to the end b of the member and causes it to rotate by θ = 0.5°, determine the normal strain in the cable. originally the cable is unstretched.