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Oct 29 2013 02:19am
Im looking to learn these stuffs so please explain to me how to get the answers. Dont just give me the answers o_o

Willing to pay fg if necessary..


1
Answer the following question by entering the numeric value with appropriate units.
If the length of one side of a square is 12.0 m, what is the perimeter of the square?
Express the perimeter to three significant figures and include the appropriate units.

2
When numbers are very small or very large, it is convenient to either express the value in scientific notation and/or by using a prefix with the unit.
A pain-relieving pill has a mass of 0.005 g. Express the pill’s mass in grams using scientific notation or in milligrams.
Express your answer in scientific notation to one significant figure or use a prefix on the unit.

3
You can also enter units that are combinations of other units. Keep in mind that you have to indicate the multiplication of units explicitly either with a multiplication dot or a dash. You can add a multiplication dot by selecting the dot dot from the symbol symbol menu menu.
The weight of an object is the product of its mass, m, and the acceleration of gravity, g (where g=9.8 m/s2). If an object’s mass is m=10. kg, what is its weight?
Express the weight to two significant figures and include the appropriate units.


4
You can enter units that are combinations of units with prefixes. However, you must maintain the same unit system given in the problem. For example, this question uses the SI unit system. Therefore an answer in U.S. customary units, such as miles per hour would not be accepted as correct.
A car traveling with constant speed travels 150 km in two hours. What is the speed of the car?
Express the speed to two significant figures and include the appropriate units.

5
You can enter compound units that are combinations of other units that are multiplied together. To enter the ⋅ explicitly, type (shift + 8) on the keyboard, or use the template in the Symbols symbol menu menu.
Torque can be calculated by multiplying the force (N) applied at 90∘ to the lever arm at a distance (m) from the pivot point (point of rotation), the compound SI unit for the torque is N⋅m. If the force (at 90∘ to the lever arm) applied is 15 N and it is applied at 2.0 m from the pivot point (point of rotation), what is the torque on the lever?
Express the torque using two significant figures and include the appropriate units.
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Oct 29 2013 03:14am
1
Answer the following question by entering the numeric value with appropriate units.
If the length of one side of a square is 12.0 m, what is the perimeter of the square?
Express the perimeter to three significant figures and include the appropriate units.
12.0m+12.0m+12.0m+12.0m=48.0m

2
When numbers are very small or very large, it is convenient to either express the value in scientific notation and/or by using a prefix with the unit.
A pain-relieving pill has a mass of 0.005 g. Express the pill’s mass in grams using scientific notation or in milligrams.
Express your answer in scientific notation to one significant figure or use a prefix on the unit.
5E(-3)g

3
You can also enter units that are combinations of other units. Keep in mind that you have to indicate the multiplication of units explicitly either with a multiplication dot or a dash. You can add a multiplication dot by selecting the dot dot from the symbol symbol menu menu.
The weight of an object is the product of its mass, m, and the acceleration of gravity, g (where g=9.8 m/s2). If an object’s mass is m=10. kg, what is its weight?
Express the weight to two significant figures and include the appropriate units.
10. kg * 9.8 m/s^2 = 98 kg*m/s^2


4
You can enter units that are combinations of units with prefixes. However, you must maintain the same unit system given in the problem. For example, this question uses the SI unit system. Therefore an answer in U.S. customary units, such as miles per hour would not be accepted as correct.
A car traveling with constant speed travels 150 km in two hours. What is the speed of the car?
Express the speed to two significant figures and include the appropriate units.
150 km/(2 hours) = 75 km/hour

5
You can enter compound units that are combinations of other units that are multiplied together. To enter the ⋅ explicitly, type (shift + 8) on the keyboard, or use the template in the Symbols symbol menu menu.
Torque can be calculated by multiplying the force (N) applied at 90∘ to the lever arm at a distance (m) from the pivot point (point of rotation), the compound SI unit for the torque is N⋅m. If the force (at 90∘ to the lever arm) applied is 15 N and it is applied at 2.0 m from the pivot point (point of rotation), what is the torque on the lever?
Express the torque using two significant figures and include the appropriate units.
15 N * 2.0 m = 30. N*m

This post was edited by Azrad on Oct 29 2013 03:15am
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Oct 29 2013 06:36pm
Suppose you are asked to find the area of a rectangle that is 2.1-cm wide by 5.6-cm long. Your calculator answer would be 11.76 cm2 . Now suppose you are asked to enter the answer to two significant figures. (Note that if you do not round your answer to two significant figures, your answer will fall outside of the grading tolerance and be graded as incorrect.)


and ty Azrad

This post was edited by Stolem on Oct 29 2013 06:36pm
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Oct 29 2013 06:40pm
A = LW.

The rule for significant figures is, if you multiply, you round to the least amount of significant figures. What we have here is 11.76 cm^2, that is four significant figures, as there is a decimal.

tl;dr it's 12 cm^2
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Oct 29 2013 09:28pm
Quote (Sefira @ Oct 30 2013 12:40am)
A = LW.

The rule for significant figures is, if you multiply, you round to the least amount of significant figures. What we have here is 11.76 cm^2, that is four significant figures, as there is a decimal.

tl;dr it's 12 cm^2


ty


Using the correct answer from Part B, calculate the volume of a rectangular prism with a length of 5.6 cm, a width of 2.1 cm, and a height of 6.6 cm.
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Oct 29 2013 09:38pm
Quote (Stolem @ Oct 29 2013 08:28pm)
ty


Using the correct answer from Part B, calculate the volume of a rectangular prism with a length of 5.6 cm, a width of 2.1 cm, and a height of 6.6 cm.

they are basically asking for the volume of a box, L*W*H
we know the L*W = 12 cm^2 so its just
12 cm^2 * 6.6 cm = 79.2 cm^3, but if we correct for sig figs, its 79 cm^3



This post was edited by Azrad on Oct 29 2013 09:39pm
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Oct 29 2013 09:49pm
the basic logic of sig figs works like this:

lets say I give you a ruler, and a disk, and ask you to calculate the area of the disk. You then measure the radius of the disk as 1.23 meters. You know the formula of the area of a circle is pi*r^2. So you go look in a book and it says pi = 3.14159265359

So then you do 3.14159265359*1.23^2 = 4.75291552562 m^2 and you turn that is as your answer. However this answer will likely be rejected because that answer implies you measured the area to that accuracy, but in fact you only measured the accuracy to 3 significant figures (1.23).. So a more honest answer would be 4.75 m^2.

Another way to phrase it is: the significant figures in your answer conveys some idea about how accurately you measured the value to a stranger who was not present when you measured it. The answer 4.75291552562 m^2 implies you used some very sophisticated equipment to measure that area, while the answer 4.75 m^2 implies you used a rather mundane process (like a ruler).

Hopefully this gives you a basic idea why it is done. The exact rules can be found here: http://en.wikipedia.org/wiki/Significant_figures#Arithmetic

This post was edited by Azrad on Oct 29 2013 09:53pm
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