Question

Considera que en tu casa tienes un televisor de 110 W, si pasa encendido 4 horas diarias, Cuál será la energía consumida durante un mes (30 días). ¿Cuál es el costo de funcionamiento si el precio de kWh es de 9 centavos

Answer 1

Answer:

a) 13.2kWh

b) 118800 cents

Explanation:

(a) To find the energy consumed during one month you use the following formula:

$E=Pt$    (1)

E: energy consumed

P: power of the tv (energy consumed per hour) = 110 W

t: time

The tv is on for four hours per day. You first calculate the number of hours, in which the tv is on, for one month:

$t=4\frac{h}{day}*\frac{30day}{1month}=120\frac{h}{month}$

Then, the tv is on 120 h on a month.

Next, you replace the values of P ant t in the equation (1) for E:

$E=(110W)(120h)=13200Wh=13.2\ kWh$

(b) If the price for kWh is 9 cents you have for the tv:

$COST=13.2kWh*\frac{9cents}{1kWh}=118800\ cents$

hence, the cost of the energy consumed  by the  tv is 118800 cents in on month

Answer 2

Answer:

 E = 13.2 kWh

,     Cost = $ 10.8

Explanation:

We can look for the consumed energy from the expression of the power

      P = W / t

The work is equal to the variation of the kinetic energy, for which

       P = E / t

       E = P t

       

look for the energy consumed in one day and multiply by the days of the month in the month

      E = 110 4 30

      E = 13200 W h

       E = 13.2 kWh

the cost of this energy is

    Cost = 0.9 12

    Cost = $ 10.8