A freezer has a coefficient of performance of 6.30. It is advertised as using 446 kWh/yr. Note: One kilowatt-hour (kWh) is an amount of energy equal to running a 1-kW appliance for one hour.
(a) On average, how much energy does it use in a single day?
(b) On average, how much energy does it remove from the refrigerator in a single day?
(c) What maximum mass of water at 19.6°C could the freezer freeze in a single day? (The latent heat of fusion of water is 3.33 105 J/kg, and its specific heat is 4186 J/kg · °C.)

a) per day

b)

c)

Explanation:

Given;

coefficient of performance of the refrigerator,

energy used per year of operation of the refrigerator,

a)

Energy used in single day:

per day

b)

Energy removed from the refrigerator in a single day:

We have the energy consumed in 1 day as,

so,

The desired effect of a refrigerator is to eliminate heat from the evaporator.

c)

Now the maximum mass of water that can freeze form 19.6°C:

where:

the independent variable, the one that is intentionally manipulated, is whether or not the car hits the barrier.

the dependent variable, the one that you measure the response in, is the distance that the washers travel.