Afan is to be selected to ventilate a bathroom whose dimensions are 2 m 3 3 m 3 3 m. the air velocity is not to exceed 8 m/s to minimize vibration and noise. the combined efficiency of the fan–motor unit to be used can be taken to be 50 percent. if the fan is to replace the entire volume of air in 10 min, determine (a) the wattage of the fan–motor unit to be purchased, (b) the diameter of the fan casing, and (c) the pressure difference across the fan. take the air density to be 1.25 kg/m3 and disregard the effect of the kinetic energy correction factors.

M= 700 kgvalue of g( gravity) is constant = 9.8 m/s² or 10 m/s² w = mg = 700*9.8 = 6860n or 6.680*10³ n

To compare speeds speeds of wagons we will use second newton's law. it states: f = m * ahere we can see that force depends on the acceleration. if we know acceleration for both wagons we can compare them to make conclusion of speeds of wagons.we have: m1 = 10lbm2 = 20lbf1 = 2*f2also: m2 = 2*m1for bill we have equation: f1 = m1 * a1for tom we have equation: f2 = m2 * a2after inserting identities we have: 2*f2 =m1 * a1f2 = 2*m1 * a2in order to make conclusions about speeds we will solve these equations for a and find their ratio: a1 = 2f2 / m1a2 = f2 / 2m1a1 / a2 = (2f2/m1) / (f2/2m1)a1 / a2 = (2f2*2m1) / (m1*f2)a1 / a2 = (4f2m1) / (m1f2)a1 / a2 = 4this ratio is bigger than 1 and this means that a1 is greater than a2. a1 is 4 times greater than a2. speed of bill's wagon is 4 times greater than speed of tom's wagon.

25,000 = 2.5 x 10⁴250 = 2.5 x 10^20.025 = 2.5 x 10⁻²0.00025 = 2.5 x 10⁻⁴