Question

4. A torque of 150 N*m is applied to a shaft rotating at 2000 rev/min a. Find the power transmitted in kilowatts b. An electrical potential of 115 V is impressed on a resistor such that a current of 9 A passes through the resistor for a period of 5 min. Find the electrical work, in KJ, and instantaneous power, in kilowatts.

Answer 1

a)
Power transmitted

$P = \frac{2\pi NT}{60}$

$P = \frac{2\pi *2000*150}{60}$

$P = 10000\pi$

$P = 31.4159 kW$

b)

Electrical Work Done

$W = V.I.t$

$W = 115*9*(5*60)$

$W = 310500 J$

$W = 310.5 kJ$

Power,

$P_{e} = \frac{W}{t}$

$P_{e} = \frac{310.5}{5*60}$

$P_{e} =1.035 kW$