Hi I am currently enrolled in PHY138Y1 and I need some major help in some homework questions.I'm a first TIME physics student and I have no idea what I'm doing. I attempted these questions, but I still dont comprehend what the question is asking for. There are some questions that I am having difficulty with. If you have any ways to help me figure it out that would be great!(adsbygoogle = window.adsbygoogle || []).push({});

Thanking You In Advance,

-Faiza Khan

Q1. The position of a particle is when moving under uniform acceleration is somefunction of the elapsed time and the acceleration. Suppose we write this position as x=kamtn, where k is a dimensionless constant. Show by dimensional analysis that this expression is satisfied if m=1 and n=2.

Can this analysis give the value of k?

Q2. At the time of a book’s printing, the U.S. national debt is

about $6 trillion.

(a) If payments were made at the rate $1000 per second, how many years would it take to pay off the debt, assuming no interest were charged?

(b) A dollar bill is about 15.5 cm long. If six trillion dollar bills were laid end to end around the earth’s equator, how many times would they encircle the earth? Take the radius of the earth at the equator to be 6 378 km.

Q3. A pirate had buried his treasure on an island with five trees, located at the following points: (30 m, -20 m), (6 m, 8 m), (-10 m, -10m), (40 m, -30m), and (-70 m, 60m), all measured relative to some origin. His ship’s log instructs you to start at tree A and move toward tree B, but to cover only one half the distance between A and B. Then move toward tree C, covering one-third the distance between your current location and C. Next move toward D, covering one-fourth the distance between where you are and D. Finally move toward E, covering one-fifth the distance between you and E, stop and dig.

(a) Assume you have correctly determined the order in which the pirate labeled the trees as A, B, C, D, and E, as shown in the figure. What are the coordinates of the point where his treasure is buried?

(b) Now rearrange the order of the trees [e.g., B (30 m, -20 m), A (60 m, 80 m), E (-10 m, -10 m), C (40 m, -30 m) and D (-70 m, 60 m)], and repeat the calculations to show that the answer does not depend on the order in which the trees are labeled.

Q4. An automobile tire is rated to last for 50 000 miles. To an order of magnitude, through how many revolutions will it turn? In your solution, state the quantities you measure or estimate and the values you take for them.

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# Homework Help: Show by dimensional analysis

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