7. [#167] Components of vectors 1 point The vector A in the (@, y) plane has magnitude A = 3.4 and makes angle 0 = 131' with the x axis, where 0 is measured in the geometric or anticlockwise sense. What are the components of A in the x and y directions? Hint: draw a sketch first. Write your answer in the form: x, y. For example: 1.5, 2.0 Use the correct number of sig figs Warning: If you retake a test, you will not necessarily get the same values of parameters the next time around. So you should calculate values again, rather than use your previous answers. Enter answer here 8. [#168] Such stuff as dreams are made of. 1 point How much of you is not vacuum? Outside of the nucleus, an atom contains mostly empty space. Estimate the fraction of the volume of an atom that is occupied by the nucleus. Assume that a typical atom has a linear dimension of about 0.1 nm and that a typical nuclear dimension is about 1 fm. (Note that this problem introduces some new prefixes: n is nano or 10 *, p is pico or 10 3, f is femto or 10-15). Give your answer as a power of ten. For example, enter: 10^18, or 10^-3 (for 1018 or 10-3). Preview will appear here... Enter math expression here11. [#1611] Nor any drop to drink 1 point Estimate the mass of water on the earth. The density of water is 1000 kg . m. Here are some approximations you can use: Compared with the oceans, lakes and rivers are tiny. Clouds have very low density. There is (still) lots of ice in the polar regions, but much less area than in the oceans. So neglect all except the oceans, which cover roughly 2/3 of the earth. Looking at charts of the oceans, we see that the depth is typically several thousand m (and a serious search tells me the average depth is 4700 mi. The radius of the earth is about 6000 km. The surface area of a sphere is ATR. This is an order or magnitude question. Express your answer in kg as a power of 10. For example, If you think the answer is 10" kg enter 10^4 This is the last question in the week 1 test. Congratulations on getting this far: we hope you have found the course so far both interesting and challenging. You will receive a mark for this test but because we run this course on demand you won't receive the worked answers or other feedback. Apologies for that. For the quizzes, however, we do give answers and feedback. 50, if you've had problems here go back and look at the relevant lessons and then do for re-do) the quizzes. Once you can do all the quiz questions these test questions should not seem too hard. Preview will appear here... Enter math expression here10. [#1610] Heartbeats 1 point How many heartbeats in a typical human lifetime? No hints for this one, and you will provide the data from your general knowledge. Enter your answer as a number (NOT as a power of ten), and don't include commas. For example, if you think the answer Is 12 million, then enter 12000000 as your answer. Enter answer here9. [#169] Bobby thumbed a diesel down. 1 point How many revolutions does the drive shaft of a truck engine make during its lifetime? Inputs: Let's suppose that the truck travels a million km (1 billion m) at an average speed of 80 km per hour. The engine turns at a rate of 2000 revolutions per minute. Hint: use the 'multiply by 1' technique and be careful: it's not difficult. However, there are several factors Involved, so we suggest that you write your answer down formally. showing all units in the working the way we did in the lesson. Give your answer as a number (not a power of ten). For example, for 40 million, write 40000090. Remember to use the appropriate number of significant figures. Hint: Using the 'mutliply by 1' calculation will tell you whether the speed should be in the numerator or the denominator. But you might be interested to think about it. It might not be obvious, because the ratio of distance travelled to turns of the engine depends on which gear the driver uses: simply stated, larger number gears require fewer turns to move the vehicle a given distance. If the distance travelled per revolution were fixed (instead of the romj and if the driving time were fixed (instead of the distance), then this would be a different question. One of our assumptions is that the distance is fixed (perhaps by the driver's employer). Further, we assume a fixed rotation rate (a given tachometer reading) for the engine (drivers of diesel engines tend to do this for efficiency). However, we don't fix the gear ratio. Enter answer here6. [#166] Subtracting vectors 1 point What is the direction of North minus West? (Hint: draw a sketch first.) North Northeast East Southeast O South Southwest West Northwest