I have a contradiction between answers for one of my HWprobs. The question is Ch
ID: 1671762 • Letter: I
Question
I have a contradiction between answers for one of my HWprobs. The question is Ch. 5 Problem 5P from Fundamentals of PhysicsExtended (8th) by Halliday, Resnick, Walker /fundamentals-of-physics-extended-8th-problem-9-332670.aspxQ: There are twoforces on a 2kg box in the overhead view of Fig 5-31, but only oneis shown. For F1 = 20 N, a = 12 m/s^2, and angle = 30. Find thesecond force a) in unitvector notation b) as amagnitude c) as an anglerelative to the positive direction of the x-axis. You use theanswer from a to answer the other two, which is why I include thewhole thing here. My problem isthat in the solution on this site, it gives the answer toa as -6i-10.39j, by the equation:12 *[cos(270-30)i + sin (270-30)j] However, theback of my book says the answer to a is:-32i-20.8j, but it doesn't show thesolution.
So my question is basically how do I solve this equation so that Ican figure out which one is right, and for the heck of it, whichone is right as well. I have a contradiction between answers for one of my HWprobs. The question is Ch. 5 Problem 5P from Fundamentals of PhysicsExtended (8th) by Halliday, Resnick, Walker /fundamentals-of-physics-extended-8th-problem-9-332670.aspx
Q: There are twoforces on a 2kg box in the overhead view of Fig 5-31, but only oneis shown. For F1 = 20 N, a = 12 m/s^2, and angle = 30. Find thesecond force a) in unitvector notation b) as amagnitude c) as an anglerelative to the positive direction of the x-axis. You use theanswer from a to answer the other two, which is why I include thewhole thing here. My problem isthat in the solution on this site, it gives the answer toa as -6i-10.39j, by the equation:12 *[cos(270-30)i + sin (270-30)j] However, theback of my book says the answer to a is:-32i-20.8j, but it doesn't show thesolution.
So my question is basically how do I solve this equation so that Ican figure out which one is right, and for the heck of it, whichone is right as well.
Explanation / Answer
You were looking at step 2, which finds a. Step 3(which finds f by multiplying by the mass) has an answerthat agrees with the back of the book. Hopefully that eliminates any confusion you had about the solutionsprovided on Cramster's site. I don't really feel like I need to provide a solution for thisproblem since you are using the one provided by Cramsteranyway. If you want me to, feel free to say so.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.