PHYSICS intro + chp 1

You have been working on an item for a while and after a few missteps you've come up with an answer. However, there is one particular thing that you're not 100%% sure of. What should you do?

Check for any hints that address the part of the calculation you're unsure about. Return to the question after you've spoken with an instructor or classmate. Submit your answer and then adjust it according to any feedback you receive.

Suppose that a particular artillery piece has a range R = 9480 yards . Find its range in miles. Use the facts that 1mile=5280 ft and 3ft= 1yard. Express your answer in miles to three significant figures.

R = 5.39 miles

Practice entering numbers that include a power of 10 by entering the diameter of a hydrogen atom in its ground state, dH=1.06×10^−10m, into the answer box. Express the diameter of a ground-state hydrogen atom in meters using a power of 10. Do not enter the units; they are provided to the right of the answer box.

dH = 1.06×10^−10 m

Similar to what you see in your textbook, you can generally omit the multiplication symbol as you answer questions online, except when the symbol is needed to make your meaning clear. For example, 1⋅10^5 is not the same as 110^5. When you need to be explicit, type * (Shift + 8) to insert the multiplication operator. You will see a multiplication dot (⋅) appear in the answer box. Do not use the symbol ×. For example, for the expression ma, typing m ⋅ a would be correct, but mxa would be incorrect.Enter the expression ma.

ma

What is the magic number? (Figure 2) Note that there is a figure also associated with this part. However, the figure for Part A may still be visible on the left. To view the figure associated with Part B, click on the figure link. A new figure should appear on the left. You could try to guess the magic number but you would probably use up all your tries before getting the answer. Notice the View Available Hint(s) link underneath the question statement for this part. Clicking this link will open up a list of clickable hints that will guide you to the correct number.

magic number = 60

For most answers, you will simply enter your numeric answer directly into the space provided to the right of the equal sign. Answer the following question by typing the numeric answer into the answer box. If you have a gross of items, you have 144 items. If you buy a gross of eggs, how many dozen eggs do you have? Express your answer in dozens. Do not enter the units; they are provided to the right of the answer box.

number of eggs = 12 dozen

The Sun, on average, is 93 million miles from Earth. a) How many meters is this? Express using powers of ten. Express your answer using two significant figures. b) Express using a metric prefix. Express your answer using two significant figures.

a) 1.5×10^11 m b) 150 gigameters

A unit of time year (yr) is defined as 365.25 days. a) How many seconds are there in 1.60 yr ? Express your answer using three significant figures. b) How many nanoseconds are there in 1.60 yr ? Express your answer using three significant figures. c) How many years are there in 1.30 s ? Express your answer using three significant figures.

a) 1.60 yr = 5.05×10^7s b) 1.60 yr = 5.05×10^16 ns c) 1.30 s = 4.12×10^−8 yr

Multiple-choice questions have a special grading rule determined by your instructor. Assume that your instructor has decided to grade these questions in the following way: If you submit an incorrect answer to a multiple-choice question with nnn options, you will lose 1/(n−1) of the credit for that question. Just like the similar multiple-choice penalty on most standardized tests, this rule is necessary to prevent random guessing. If a multiple-choice question has five answer choices and you submit one wrong answer before getting the question correct, how much credit will you lose for that part of the question?

25%

Enter the expression 2cos^2(θ)−1, where θ is the lowercase Greek letter theta.

2cos^2(θ)−1

To eight significant figures, Avogadro's constant is 6.0221367 × 10^23 mol^−1. Which of the following choices demonstrates correct rounding? Check all that apply.

6.022 × 10^23 mol−1 6.0 × 10^23 mol−1 6.02214 × 10^23 mol−1

You've just solved a problem and the answer is the mass of an electron, me=9.11×10^−31kilograms. How would you enter this number into the answer box?

9.11×10^−31 kilograms

How many centimeters are there in a length 36.5 inches? Express your answer in centimeters to three significant figures.

92.7 cm

If you are asked to provide a set of two or more numeric answers, separate them with commas. For example, to provide the year that Sputnik (the first satellite to be sent into orbit around the Earth) was launched and the year humans first walked on the Moon, you would enter 1957,1969 in the answer box. A rectangle has a length of 5.50 mm and a width of 12.0 mm. What are the perimeter and area of this rectangle? Enter the perimeter and area numerically separated by a comma. The perimeter should be given in meters and the area in square meters. Do not enter the units; they are provided to the right of the answer box.

perimeter, area = 35.0,66.0 m, m2

Enter the expression asin(x)+15 , where asin(x) is the inverse sine function. Alternatively, you may enter the inverse sine function in either of the following forms, which are also accepted: arcsin(x) or sin^−1(x).

sin^−1(x)+15

Enter the expression N0e^−λt, where N0 is N-naught (an N with a subscript zero) and λ is the lowercase Greek letter lambda.

N0e^−λt

How many squares are in this 2×2 grid (Figure 1)? Note that the figure link lets you know that a figure goes along with this part. This figure is available to the left. Enter your answer as a number in the box below and then submit your answer by clicking Submit.

Number of squares = 5

To seven significant figures, the mass of a proton is 1.672623 × 10^−27 kg. Which of the following choices demonstrates correct rounding? Check all that apply.

1.67 × 10^−27kg

A friend in your class tells you that she never uses hints when doing her Mastering homework. She says that she finds the hints helpful, but when the hint asks another question it increases the chance that her score on the problem will go down. She feels like it isn't worth the risk. You reassure her that there is nothing to fear about opening a hint that asks a question. Which of the following are good reasons for your friend not to worry?

Getting the correct answer to the question in a hint actually gives you some partial credit, even if you still can't answer the original question. As an incentive for thinking hard about the problem, your instructor may choose to apply a small hint penalty, but this penalty is the same whether the hint simply gives information or asks another question. The only way to lose additional partial credit on a hint is by using the "Request Answer" button or entering incorrect answers. Leaving the question blank will not cost you any credit.

You are starting a new item and after reading the first part you realize you have no idea how to go about answering it. What should you do?

Use the available hints.

Still think that unit conversion isn't important? Here is a widely publicized, true story about how failing to convert units resulted in a huge loss. In 1998, the Mars Climate Orbiter probe crashed into the surface of Mars, instead of entering orbit. The resulting inquiry revealed that NASA navigators had been making minor course corrections in SI units, whereas the software written by the probe's makers implicitly used British units. In the United States, most scientists use SI units, whereas most engineers use the British, or Imperial, system of units. (Interestingly, British units are not used in Britain.) For these two groups to be able to communicate to one another, unit conversions are necessary. The unit of force in the SI system is the newton (N), which is defined in terms of basic SI units as 1N=1kg⋅m/s^2. The unit of force in the British system is the pound (lb), which is defined in terms of the slug (British unit of mass), foot (ft), and second (s) as 1lb=1slug⋅ft/s^2. a) Find the value of 15.0 N in pounds. Use the conversions 1slug=14.59kg and 1ft=0.3048m. Express your answer in pounds to three significant figures.

a) 15.0 N = 3.37 lb

a) How many significant figures does 214 have? b) How many significant figures does 81.60 have? c) How many significant figures does 7.03 have? d) How many significant figures does 0.03 have? e) How many significant figures does 0.0086 have? f) How many significant figures does 3236 have? g) How many significant figures does 8700 have?

a) 3 b) 4 c) 3 d) 1 e) 2 f) 4 g) 4

A light-year (ly) is the distance light travels in one year (at speed of 2.998 × 108 m/s ). An astronomical unit (AU) is the average distance from the Sun to Earth, 1.50 × 10^8 km. 1 year = 3.156 × 10^7 s. a) How many meters are there in 3.90 ly? Express your answer using three significant figures. b) How many AU are there in 3.90 ly light-year? Express your answer using three significant figures.

a) 3.90 ly = 3.69 × 10^16 m b) 3.90 ly = 2.46×10^5 AU

Here is a simple example. The inhabitants of a small island begin exporting beautiful cloth made from a rare plant that grows only on their island. Seeing how popular the small quantity that they export has been, they steadily raise their prices. A clothing maker from New York, thinking that he can save money by "cutting out the middleman," decides to travel to the small island and buy the cloth himself. Ignorant of the local custom of offering strangers outrageous prices and then negotiating down, the clothing maker accepts (much to everyone's surpise) the initial price of 400 tepizes/m2. The price of this cloth in New York is 120 dollars/yard^2. a) If the clothing maker bought 500 m^2 of this fabric, how much money did he lose? Use 1tepiz=0.625dollar and 0.9144m=1yard. Express your answer in dollars using two significant figures.

a) 5.3×10^4 dollars

a) How many seconds are there in 3.00 year? b) How many nanoseconds are there in 3.00 year? c) How many years are there in 3.00 second?

a) 9.47×10^7 s b) 9.47×10^16 ns c) 9.51×10^−8 y

When entering large numbers in the answer box, do not use commas. For example, enter 1276400‎ for the number 1,276,400. Do not enter 1,276,400‎. If you accidentally enter commas, you will receive feedback as a reminder. Answer the following question by typing the numeric answer into the answer box. What is the sum of 9260 and 3240? Express your answer numerically to at least three significant figures.

sum = 12500

What is the speed of a car going v= 1.000 mph in SI units? Notice that you will need to change from miles to meters and from hours to seconds. You can do each conversion separately. Use the facts that 1mile= 1609 m and 1hour= 3600 s. Express your answer in meters per second to four significant figures.

v = 0.4469 m/s

Enter the expression √2gΔy/m, where Δ is the uppercase Greek letter Delta. Note: the term Δy represents a single variable, not two separate variables multiplied together.

√2gΔy/m