Author Question: The approximate daily energy consumption of primitive humans (before fire) was about a. 2000 ... (Read 49 times)

skymedlock · **on:** Jul 28, 2018

The approximate daily energy consumption of primitive humans (before fire) was about

a. 2000 kilojoules.
b. 8000 kilojoules.
c. 12,000 kilojoules.
d. 48,000 kilojoules
e. 400,000 kilojoules.

Question 2

A stay-at-home mom watches soap operas for 1.5 h each day and her husband vegges out in front of the tube for around 2 h a night.

He also watches the football games on Saturday and Sunday during football season (two games each day, 6 hours of watching). How much does this family pay to watch TV every year? Assume the cost of electricity is 0.08/kWh.

bblaney · **Reply #1 on:** Jul 28, 2018

Answer to Question 1

B

Answer to Question 2

We assume from the description that this is the weekday ritualwatching the TV
for a total time of 3.5 h. From Table 8.7, we use 200 W as the power drawn by the TV. So,
we find 5 d x 3.5 h/d x 200 W = 3500 Wh = 3.5 kWh. Weekend watching totals 12 h, so
energy use from the weekend totals 200 W x 12 h = 2400 Wh = 2.4 kWh. Total weekly
energy use is 5.9 kWh. The cost is 5.9 kWh x 0.08/kWh = 0.47.