Thursday

July 24, 2014

July 24, 2014

Posted by **julie** on Monday, March 14, 2011 at 7:02pm.

(a) At a rate of $0.060/kWh, what is the cost, in cents, of operating the motor for 4.0 h?

(b) What is the efficiency of the motor?

for (a) i am doing IV*hours*price and its coming up worng.

and for (b) i changed .2hp into Watts. and i got 149.2W.

im just not sure how to do this problem.

- physics -
**Henry**, Tuesday, March 15, 2011 at 10:57pmPin=VI=110 * 1.76=193.6W = 0.1936KW.

a. C = $0.060/kwh * 0.1936kw * 4h =

$0.0465 = 4.65 cents.

b. Po = 0.2hp * 746W/hp = 149.2W.

%Eff.=(Po/Pin)100%,

%Eff.=(149.2/193.6)100% = 77.1

**Related Questions**

physics - A 120-V motor has mechanical power output of 2.20 hp. It is 92.0% ...

physics - A 120-V motor has mechanical power output of 3.20 hp. It is 81.0% ...

Physics - A 120-V motor has mechanical power output of 2.00 hp. It is 82.0% ...

algebra - The power (P) required to run a motor is equal to the voltage (E) ...

physics - The electrical motor runs on a D.C source of emf E and internal ...

electrical engineering - A three phase, four- pole, 30-hp, 220-V, 60-Hz, Y-...

physics - A 120-V motor has mechanical power output of 2.20 hp. It is 92.0% ...

Electricity - A motor running at its rated power provides 2.6 lb-ft torque at ...

Physics - An electric motor has 72 turns of wire wrapped on a rectangular coil, ...

Physics - A 120.0 volt motor draws a current of 7.60 A when running at normal ...