coach94

Two wooden crates rest on top of one another. The smaller top crate has a mass of m₁ = 17 kg and the larger bottom crate has a mass of m₂ = 92 kg. There is NO friction between the crate and the floor, but the coefficient of static friction between the two crates is μ_s = 0.8 and the coefficient of kinetic friction between the two crates is μ_k = 0.62. A massless rope is attached to the lower crate to pull it horizontally to the right (which should be considered the positive direction for this problem).

1)

The rope is pulled with a tension T = 248 N (which is small enough that the top crate will not slide). What is the acceleration of the small crate? 2.275 m/s^2

2) In the previous situation, what is the frictional force the lower crate exerts on the upper crate? 38.675 N

3) What is the maximum tension that the lower crate can be pulled at before the upper crate begins to slide? 854.56N

4) The tension is increased in the rope to 1223 N causing the boxes to accelerate faster and the top box to begin sliding. What is the acceleration of the upper crate? 6.076 m/s^2

5)

As the upper crate slides, what is the acceleration of the lower crate? this is the only one that I could not figure out

I know all my answers for 1-4 are correct but i cant seem to get the answer to 5. If someone could help me with an equation it'd be appreciated

edit:

QUESTION HAS BEEN RESOLVED

Yes, if that is what your instructor wants.

alright cool thanks for the help man appreciate it

One big logic matrix with all inputs, gates and the output.

oh okay so its fine how i have it written then

Those are correct for each of W, V, and X, but they aren't combined.

what do you mean by not combined?

Yes, grats. You can write the equations as follows:

W(d,c) = d .or. c = w

V(b,a) = b .xor. a = v

X(w, v) = w .and. v = (d .or. c) .and. (b .xor. a) = f

cool thanks!

one last question though, would the truth tables look something like this?

W's

DC|X <- x because it goes through X right

00|0

01|1

10|1

11|1

X's

WV|F <- F because this is where F is derived?

00|0

01|0

10|0

11|1

V's

BA|X <- x because it goes through X right?

00|0

01|1

10|1

11|0

my professor never taught us how to construct them so im trying my best to go from the book but im not too sure

Either you are guessing or you have given me incorrect information. You said V was .xor., what are the inputs to V? You said X was .and., what are the inputs to X?

Sorry im working on multiple things at once i mis-read my own question

(D+C).(B(xor symbol)A)

should be correct now id think

Then the expression "(d+c)(ba)" cannot represent the circuit as shown; although, it may be equivalent (I haven't worked it out). Again, write each of the subexpressions for W, V and X separately.

I think ive figured it out.

(D+C) <- would be W

(B.A) <- would be V

and to put them together tying in the xor the final expression would be

(D+C) (xor symbol) (B.A) ?

i think that would be right?

Why are you concerned only about X? The expression "(d+c)(ba)" doesn't mention W, V, X or f. Perhaps you will realize the answer if you write down separately what W and V do (label the lines between W and X and V and X), and the value of f.

woops forgot a key piece of information haha!

W is an OR gate, X is an AND gate, V is an XOR gate

I have this diagram

I am trying to find the boolean equation for this.

I know

(d+c)(ba)

I dont know how to write the equation to include the box X

anyone give me a hand?

would you be able to check if im going in the right direction with this? Just want to make sure I got the first one done correctly i have about 30 more to do lol.

from the whole example i provided, i got

B+D'C'+D'+C'

would you be able to check if im going in the right direction with this? Just want to make sure I got the first one done correctly i have about 30 more to do lol.

 

from the whole example i provided, i got

 

B+D'C'+D'+C'

actually cant you combine it to be

B+D'+C'

 

The second does not follow from the first, since you have one A' and one A

 

How about trying the fourth and fifth terms?

but wouldnt

A+A'=1

imply that those a's would be 1?

and for the 4th and 5th terms

it would go

D'CB(A+A')?

which would be

D'CB?

So what I got from the last two would be

DC'B'A' + DC'BA =

DC'B' + DC'B =

DC' + DC' =

C'(D+C)?

Just so there is no misunderstanding,

 

1. Does A+B mean A or B or A exclusive or B?

2. Does D' mean not D?

3. Does AB mean A and B?

4. Is there any significance to your underlining the entire equation: D'C'B'A+D'C'BA'+D'C'BA+D'CBA'+D'CBA+DC'B'A'+DC'BA? If the underline means the entire equation is not equation then use one of the laws to change it to another form without the not. If this is why you cannot start, make the whole thing look simpler by renaming each of the term+term+term....

 

I recommend you put parenthesis around a couple of the terms and see if you can simplify the things in parenthesis. Use the laws (monotone, nonmonotone, and De Morgan's) to simplify.

 

Try something and show your work. Check your work with a K-map, just don't turn it in.

1. means or

2. correct

3. yes

4. no just underlined it just because ( probably shouldn't do that )

Now when Im doing this, can i take say an A' from the second set of terms and match it with one from lets say the second to last set of terms? Do i have to go in a specific order? And do the rules apply to other variables the same? or do they work just as a or b?

Come on, can you not start collecting terms together and simplifying?

 

You also have a bunch of more basic rules like

 

A.A=A

A+A=A

A.1=A

A+A'=1

AA'=0

(A')'=A

A+B=B+A

A+B+C=A+(B+C)=(A+B)+C

ABC=A(BC)=(AB)C

A(B+C)=AB+AC

 

So for instance in your example you have

 

D'C'BA+D'C'BA'

 

=D'C'B(A+A')

 

and what is (A+A')?

(A+A') would be 1 right?

Do you know the rules of boolean algebra as algebra?

 

A+AB = A

A(A+B)=A

A(A'+B)=AB

A+A'B=A+B

A+BC=(A+B)(A+C)

(AB)'=(A'+B')

A'B'=(A+B)'

 

The last two make up De Morgan's Theorem.

 

Alternatively you could use Venn Diagrams.or switch diagrams

I've seen those rules a few times before, But i dont see how they will help me when I have 4 variables not just 2 or 3?

I can't use K-Map's i only can use boolean algebra to solve these problems

This is an example of one of the many things i need to simplify using boolean algebra

D'C'B'A+D'C'BA'+D'C'BA+D'CBA'+D'CBA+DC'B'A'+DC'BA

Any kind of help is appreciated, I honestly dont even know where to start.

Ive been stuck on this problem for a bit, I'm not exactly sure what equation to use to solve it so any help pointing me in the right direction is appreciated!

You are traveling on an airplane. The velocity of the plane with respect to the air is 120 m/s due east. The velocity of the air with respect to the ground is 44 m/s at an angle of 30° west of due north.

what ive found : planes speed relative to the ground is 105.15 m/s

question i can't figure out :

1) What is the heading of the plane with respect to the ground? (Let 0° represent due north, 90° represents due east).

Ive been stuck on this problem for a bit, I'm not exactly sure what equation to use to solve it so any help pointing me in the right direction is appreciated!

You are traveling on an airplane. The velocity of the plane with respect to the air is 120 m/s due east. The velocity of the air with respect to the ground is 44 m/s at an angle of 30° west of due north.

what ive found : planes speed relative to the ground is 105.15 m/s

question i can't figure out :

1) What is the heading of the plane with respect to the ground? (Let 0° represent due north, 90° represents due east).

ahh that would explain it! cool man thanks for the help i appreciate it.

Here are a couple of links to ASCII. Think of ASCII (any character code) as a cipher that converts character icons into binary numbers that the computer can store and use. There is nothing inside a computer except numbers, regardless of how the magic of software makes it look like computers contain videos, pictures, text, etc; everything is converted into numbers that a computer can process.

 

http://en.wikipedia.org/wiki/Ascii

http://en.wikipedia.org/wiki/Extended_ASCII

http://www.asciitable.com/

Thank you for that, I figured out how to convert the numbers, but for 9 in the table for example, under Code(H) I am getting 01011111 rather than what is shown (00100000) any idea on what I am doing wrong? I do use the 128,64,32,16,8,4,2,1 setup for this correct?

I need some help with converting from roman numerals to ASCII code.

I would just like a better understanding of how to do it

My teacher gave us the following table and we have to get the rest of the code ( 0-6, 10-12)

and i honestly have no clue where to go when it comes to the ASCII code I cant really find any good resources online to figure it out.