Answer:
The system loses 90 kJ of heat
Explanation:
We can answer the question by using the 1st law of thermodynamics, which states that:
where
is the change in internal energy of the system
is the heat absorbed by the system (positive if absorbed, negative if released by the system)
is the work done by the system (positive if done by the system, negative if done by the surrounding on the system)
In this problem, we have:
is the work done (negative, because it is done by the surrounding on the system)
is the increase in internal energy
Using the equation above, we can find Q, the heat absorbed/released by the system:
And the negative sign means that the system has lost this heat.
Answer: 40.650406504065 or 40 minutes and 39 seconds.
Explanation:
1 k = 1000m
race = 10000m
runner time = 10000 / 4.1
runner time = 2439.0243902439024 seconds
runner time = 2439.0243902439024/60 = 40.650406504065 or 40 minutes and 39 seconds.
Answer:
(A) power = 0.208 kW = 208 watts
(B) energy = 6.6 x 10^{9} joules
Explanation:
energy consumed per day = 5 kWh
(a) find the power consumed in a day
1 day = 24 hours
power = \frac{energy}{time}
power = \frac{5}{24}
power = 0.208 kW = 208 watts
(b) find the energy consumed in a year
assuming it is not a leap year and number of days = 365 days
1 year = 365 x 24 x 60 x 60 = 31,536,000 seconds
energy = power x time
energy = 208 x 31,536,000
energy = 6.6 x 10^{9} joules
