Ek 1001 Physics # 285

[eldoctor]

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Maybe I'm doing the math wrong, but the answer in the back of the book says "C" and gives the formula mg + T3 + ma = T2.

mg = 10g
T3 = 10g
ma = 10(2)


Why is this not equal to "B" (220 N)??

 

[GRod18]

for future reference if you want an reply back quicky from many experts here, you should type out the entire question and explain simple pictures/diagrams.

T1-----BoxA---T2-----------BoxB----------T3------------BoxC

here is the diagram but actual diagram is vertical. With boxes.

I believe I also had trouble with EK's explanation on this problem, but I believe that they mistakenly said that m = mass of box B. If we are balancing T2 with everything that is below it. We should set T2 = mg (B) + mg (c) + Ma (where M is mass of box B + mass of box C.)

So T2 = 10(10) + 10(10) + 20(2) = 240 N


ya I was right,

check out similar question in this thread

http://forums.studentdoctor.net/showthread.php?t=424422

 

[Rabolisk]

I'm not sure I get the question. I think I get the diagram, but what is being asked and what are the parameters given?

 

[GRod18]

I'm not sure I get the question. I think I get the diagram, but what is being asked and what are the parameters given?

Question states:

Boxes A,B, and C each have a mass of 10kg. If the boxes are accelerated upwards at 2m/s^2, what is the tension T2?

 

[eldoctor]

for future reference if you want an reply back quicky from many experts here, you should type out the entire question and explain simple pictures/diagrams.

T1-----BoxA---T2-----------BoxB----------T3------------BoxC

here is the diagram but actual diagram is vertical. With boxes.

I believe I also had trouble with EK's explanation on this problem, but I believe that they mistakenly said that m = mass of box B. If we are balancing T2 with everything that is below it. We should set T2 = mg (B) + mg (c) + Ma (where M is mass of box B + mass of box C.)

So T2 = 10(10) + 10(10) + 20(2) = 240 N


ya I was right,

check out similar question in this thread

http://forums.studentdoctor.net/showthread.php?t=424422

Thank you, I was pretty certain that the problem had to do with the mass that EK said to use. I don't like the explanations to the physics problems tbh. EK Bio and Verbal are much better

 

[GRod18]

Thank you, I was pretty certain that the problem had to do with the mass that EK said to use. I don't like the explanations to the physics problems tbh. EK Bio and Verbal are much better

Keep doing it if your not strong in physics like I am, EK is designed to drill equations into your head. Some of these problems are not MCAT style because they are pretty much taken out of physics text books and made into multiple choice problems. If you have questions, there are plenty of nice people/future doctors on this site that will help.