Homework Clinic
Science Clinic => Physics => Topic started by: cdr_15 on Jul 27, 2018
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Compared with the standard hour of 60 minutes used today, the hour of ancient Egypt
A) was longer than the hour used today.
B) was shorter than the hour used today.
C) differed in length depending on the pharaoh in power at the time.
D) was longer than 60 minutes in the summer and shorter than 60 minutes in the winter.
E) divided the entire day into 12 equal parts.
Question 2
Briefly describe the four possible expansion patterns of the universe.
What will be an ideal response?
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Answer to Question 1
D
Answer to Question 2
1. Recollapsing universe: the density of the universe is greater than critical. Gravity will eventually reverse the expansion, resulting in a Big Crunch.
2. Critical universe: the density of the universe is equal to the critical density. Gravity just balances the expansion which slows increasingly down toward zero as time progresses.
3. Coasting universe: the density of the universe is less than the critical density. The expansion overwhelms the attractive force of gravity and the universe expands without limit.
4. Accelerating universe: a mysterious repulsive force that acts against gravity on large scales causes the universe to expand with ever-increasing speed.
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Thank you!
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Always glad to help...