Answer:
The temperature after half an hour is 
Solution:
As per the question;
Metabolic rate of the person is 3.0105 J/h
Temperature, T = 
Mass of the water, 
Time duration, t = 0.5 h = 30 min = 180 s
Now,
Heat, 
Thus heat transfer in half an hour:

Now, the temperature of water after half an hour, T' is given by:

where
s = 4186 J


The first thing we must do for this case is the sum of forces in a horizontal direction.
We have then:

Substituting values we have:

From here, we clear the mass of the object:

We now look for the weight of the object.

Where,
g: acceleration of gravity (9.8 m/s^2)
Substituting values:

Answer:
the weight of the object is:

option 4
Explanation:
thet amplify DC, because of the voltage ( small current input signal)
Answer:
The cost of energy is $ 0.34.
Explanation:
The energy is the capacity to do work.
The energy is a scalar quantity and its SI unit is Joule.
The commercial unit of energy is kWh.
Cost of 1 kWh energy = $ 0.17
energy loss by standard window is 2 kWh .
So, the cost of lost of energy is
Cost = $ 0.17 x 2 = $ 0.34