(a) Derive the differential equation for small motion of the mass m shown in Figure P7.18a. Consider the bar to be weightless. (b) A partially filled oil drum floats in the sea, as shown in Figure...

(a) Derive the differential equation for small motion of the mass m shown in Figure P7.18a. Consider the bar to be weightless. (b) A partially filled oil drum floats in the sea, as shown in Figure P7.18b. Determine the frequency of vertical motion as it bobs up and down. Seawater mass density = 1.025.