course PHY 201
......!!!!!!!!...................................
16:33:56 `q001. There are 10 questions and 5 summary questions in this assignment. How many cubic centimeters of fluid would require to fill a cubic container 10 cm on a side?
......!!!!!!!!...................................
RESPONSE --> it would take 1000cm^3 of fluid to fill the cube. The formula for the volume of a cube is a^3, where a is the length of the sides.
.................................................
......!!!!!!!!...................................
16:34:00 The volume of the container is 10 cm * 10 cm * 10 cm = 1000 cm^3. So it would take 1000 cubic centimeters of fluid to fill the container.
......!!!!!!!!...................................
RESPONSE --> ok
.................................................
......!!!!!!!!...................................
16:37:48 `q002. How many cubes each 10 cm on a side would it take to build a solid cube one meter on a side?
......!!!!!!!!...................................
RESPONSE --> It would take 10 of the 10cm blocks to equal one meter. Then we would multiply by 6 because the cube is solid. So we would need 60 blocks.
.................................................
......!!!!!!!!...................................
16:38:19 It takes ten 10 cm cubes laid side by side to make a row 1 meter long or a tower 1 meter high. It should therefore be clear that the large cube could be built using 10 layers, each consisting of 10 rows of 10 small cubes. This would require 10 * 10 * 10 = 1000 of the smaller cubes.
......!!!!!!!!...................................
RESPONSE --> ok. I see where I went wrong. It was hard to visualize the problem.
.................................................
......!!!!!!!!...................................
16:41:07 `q003. How many square tiles each one meter on each side would it take to cover a square one km on the side?
......!!!!!!!!...................................
RESPONSE --> To cover only one square of one side...and since there are 1000 meters in one kilometer, we would need 1000 x 1000 = 1000000 tiles.
.................................................
......!!!!!!!!...................................
16:41:22 It takes 1000 meters to make a kilometer (km). To cover a square 1 km on a side would take 1000 rows each with 1000 such tiles to cover 1 square km. It therefore would take 1000 * 1000 = 1,000,000 squares each 1 m on a side to cover a square one km on a side. We can also calculate this formally. Since 1 km = 1000 meters, a square km is (1 km)^2 = (1000 m)^2 = 1,000,000 m^2.
......!!!!!!!!...................................
RESPONSE --> ok. I understand this, but i forgot to put my units.
.................................................
......!!!!!!!!...................................
16:42:27 `q004. How many cubic centimeters are there in a liter?
......!!!!!!!!...................................
RESPONSE --> there are 1000cm^2 in one liter.
.................................................
......!!!!!!!!...................................
16:42:32 A liter is the volume of a cube 10 cm on a side. Such a cube has volume 10 cm * 10 cm * 10 cm = 1000 cm^3. There are thus 1000 cubic centimeters in a liter.
......!!!!!!!!...................................
RESPONSE --> ok
.................................................
......!!!!!!!!...................................
16:43:18 `q005. How many liters are there in a cubic meter?
......!!!!!!!!...................................
RESPONSE --> there are 1000 liters in one cubic meter.
.................................................
......!!!!!!!!...................................
16:43:44 A liter is the volume of a cube 10 cm on a side. It would take 10 layers each of 10 rows each of 10 such cubes to fill a cube 1 meter on a side. There are thus 10 * 10 * 10 = 1000 liters in a cubic meter.
......!!!!!!!!...................................
RESPONSE --> ok
.................................................
......!!!!!!!!...................................
16:44:26 `q006. How many cm^3 are there in a cubic meter?
......!!!!!!!!...................................
RESPONSE --> There are 1,000,000 cubic centimeters in one cubic meter.
.................................................
......!!!!!!!!...................................
16:44:28 There are 1000 cm^3 in a liter and 1000 liters in a m^3, so there are 1000 * 1000 = 1,000,000 cm^3 in a m^3. It's important to understand the 'chain' of units in the previous problem, from cm^3 to liters to m^3. However another way to get the desired result is also important: There are 100 cm in a meter, so 1 m^3 = (1 m)^3 = (100 cm)^3 = 1,000,000 cm^3.
......!!!!!!!!...................................
RESPONSE --> ok
.................................................
......!!!!!!!!...................................
16:47:23 `q007. If a liter of water has a mass of 1 kg the what is the mass of a cubic meter of water?
......!!!!!!!!...................................
RESPONSE --> since 1 liter is equal to .001 cubic meters, then the mass would be .001 kg
.................................................
......!!!!!!!!...................................
16:47:48 Since there are 1000 liters in a cubic meter, the mass of a cubic meter of water will be 1000 kg. This is a little over a ton.
......!!!!!!!!...................................
RESPONSE --> ok. I had my math backwards. I see where i went wrong.
.................................................
......!!!!!!!!...................................
12:51:43 `q008. What is the mass of a cubic km of water?
......!!!!!!!!...................................
RESPONSE --> There would be 1 kg in a cubic kilometer of water.
.................................................
......!!!!!!!!...................................
12:53:10 06-16-2005 12:53:10 A cubic meter of water has a mass of 1000 kg. A cubic km is (1000 m)^3 = 1,000,000,000 m^3, so a cubic km will have a mass of 1,000,000,000 m^3 * 1000 kg / m^3 = 1,000,000,000,000 kg. In scientific notation we would say that 1 m^3 has a mass of 10^3 kg, a cubic km is (10^3 m)^3 = 10^9 m^3, so a cubic km has mass (10^9 m^3) * 1000 kg / m^3 = 10^12 kg.
......!!!!!!!!...................................
NOTES -------> Ok, I had my math backwards again. I am writing down the conversions but getting confused on how to tie them all together. I see where I went wrong...and have saved this as notes.
.......................................................!!!!!!!!...................................
13:01:18 `q009. If each of 5 billion people drink two liters of water per day then how long would it take these people to drink a cubic km of water?
......!!!!!!!!...................................
RESPONSE --> It will take .01 of a day to drink a km^3 of water.
.................................................
......!!!!!!!!...................................
13:26:13 5 billion people drinking 2 liters per day would consume 10 billion, or 10,000,000,000, or 10^10 liters per day. A cubic km is (10^3 m)^3 = 10^9 m^3 and each m^3 is 1000 liters, so a cubic km is 10^9 m^3 * 10^3 liters / m^3 = 10^12 liters, or 1,000,000,000,000 liters. At 10^10 liters per day the time required to consume a cubic km would be time to consume 1 km^3 = 10^12 liters / (10^10 liters / day) = 10^2 days, or 100 days. This calculation could also be written out: 1,000,000,000,000 liters / (10,000,000,000 liters / day) = 100 days.
......!!!!!!!!...................................
RESPONSE --> Once again, I had my math backwards. I have written the math the same as described here, but it's hard for me to visualize the way it should be worked out. I understand from looking at the solution, but before I could see the answer, I didn't know exactly how to approach the math.
.................................................
......!!!!!!!!...................................
13:34:21 `q010. The radius of the Earth is approximately 6400 kilometers. What is the surface area of the Earth? If the surface of the Earth was covered to a depth of 2 km with water that what would be the approximate volume of all this water?
......!!!!!!!!...................................
RESPONSE --> The surface area of the earth would be equal to 4 pi r^2 or 163,840,000 pi km^2. The volume of the water placed in the earth would be equal to h pi r^2 or (2) pi 6400^2 = 81,920,000 pi km^3.
.................................................
......!!!!!!!!...................................
13:35:50 The surface area would be A = 4 pi r^2 = 4 pi ( 6400 km)^2 = 510,000,000 km^2. A flat area of 510,000,000 km^2 covered to a depth of 2 km would indicate a volume of V = A * h = 510,000,000 km^2 * 2 km = 1,020,000,000 km^3. However the Earth's surface is curved, not flat. The outside of the 2 km covering of water would have a radius 2 km greater than that of the Earth, and therefore a greater surface area. However a difference of 2 km in 6400 km will change the area by only a fraction of one percent, so the rounded result 1,020,000,000,000 km^3 would still be accurate.
......!!!!!!!!...................................
RESPONSE --> OK. For these formulas, I used the same formulas but got another number since I did not multiply pi out. How do we know when we should or should not multiply out pi?
.................................................
......!!!!!!!!...................................
13:38:02 `q011. Summary Question 1: How can we visualize the number of cubic centimeters in a liter?
......!!!!!!!!...................................
RESPONSE --> With problems like this, it is probably better for me to memorize the conversions than to try to visualize the problem. When I do that, I just get confused.
.................................................
......!!!!!!!!...................................
13:38:51 Since a liter is a cube 10 cm on a side, we visualize 10 layers each of 10 rows each of 10 one-centimeter cubes, for a total of 1000 1-cm cubes. There are 1000 cubic cm in a liter.
......!!!!!!!!...................................
RESPONSE --> ok. I can see this when it is stated for me, but I associate a liter as something liquid, rather than a block.
.................................................
......!!!!!!!!...................................
13:40:17 `q012. Summary Question 2: How can we visualize the number of liters in a cubic meter?
......!!!!!!!!...................................
RESPONSE --> I would memorize the conversions. However, it could be similar to the previous question where you viewed it as a block made up of smaller units.
.................................................
......!!!!!!!!...................................
13:40:22 Since a liter is a cube 10 cm on a side, we need 10 such cubes to span 1 meter. So we visualize 10 layers each of 10 rows each of 10 ten-centimeter cubes, for a total of 1000 10-cm cubes. Again each 10-cm cube is a liter, so there are 1000 liters in a cubic meter.
......!!!!!!!!...................................
RESPONSE --> ok
.................................................
......!!!!!!!!...................................
13:41:06 `q013. Summary Question 3: How can we calculate the number of cubic centimeters in a cubic meter?
......!!!!!!!!...................................
RESPONSE --> We could multiply the cm^3 by 10 to get to meters.
.................................................
......!!!!!!!!...................................
13:41:20 One way is to know that there are 1000 liters in a cubic meters, and 1000 cubic centimeters in a cubic meter, giving us 1000 * 1000 = 1,000,000 cubic centimeters in a cubic meter. Another is to know that it takes 100 cm to make a meter, so that a cubic meter is (100 cm)^3 = 1,000,000 cm^3.
......!!!!!!!!...................................
RESPONSE --> I meant to put 100. But ok.
.................................................
......!!!!!!!!...................................
13:42:11 `q014. Summary Question 4: There are 1000 meters in a kilometer. So why aren't there 1000 cubic meters in a cubic kilometer? Or are there?
......!!!!!!!!...................................
RESPONSE --> I always thought that there were 1000m^3 in 1 km^3.
.................................................
......!!!!!!!!...................................
13:42:32 06-16-2005 13:42:32 A cubic kilometer is a cube 1000 meters on a side, which would require 1000 layers each of 1000 rows each of 1000 one-meter cubes to fill. So there are 1000 * 1000 * 1000 = 1,000,000,000 cubic meters in a cubic kilometer. Alternatively, (1 km)^3 = (10^3 m)^3 = 10^9 m^3, not 1000 m^3.
......!!!!!!!!...................................
NOTES -------> Ok. I understand this and have taken note of it.
.......................................................!!!!!!!!...................................
13:43:11 `q015. Explain how you have organized your knowledge of the principles illustrated by the exercises in this assignment.
......!!!!!!!!...................................
RESPONSE --> I have made a list of the conversions and the mistakes I've made on each problem as I go along. Hopefully, it will help me in future problems.
.................................................
......!!!!!!!!...................................
13:43:15 This ends the fourth assignment.
......!!!!!!!!...................................
RESPONSE --> ok
........"