2. A pendulum is a mechanical system in which a mass m is attached to a massless inextensible string of length pivot ( which is in turn connected to a frictionless pivot, as shown at right. The swing angle 0(t) of the pendulum satisfies the second-order nonlinear differential equation H d20 dt2 + - sin 0 = 0. The transformation v = de allows us to transform this mass m equation into the separable first-order differential equa- tion dv v de + - sin 0 = 0. (1) (a) If the mass m is initally at rest at an angle of do = 7/4 degrees, solve the differ- ential equation (1) to find v = v(0)