# Homework Help: How much work done by friction when a box w/apparent mass..?

1. Nov 19, 2016

### jmm5180

1. The problem statement, all variables and given/known data
How much work is done by friction when a box with an apparent mass of 325kg moves horizontally across a floor with coefficient of friction of .33 and is pulled at 59.9 degree angle for 2.60 m? What is the force that is pulling the box?

2. Relevant equations
W=Fdcos@ (@= theta)
Fnet=ma

3. The attempt at a solution
I searched for what apparent mass was, but what I found seemed to do with volume and water displacement, which aren't related to this problem. Instead I tried solving the second question first because I needed Normal force to solve the work done by friction.

For my free body diagram, I had force applied (Fa) in the y direction upwards on the y axis along with normal force. Along the negative y axis I had weight. Force of friction (Ff) was along the negative x axis, and force applied in the x direction was on the positive x axis.

In the x direction...
Ff=Facos@ (since no acceleration)
uN = FaCos@

In the y direction...
Fasin@ + N = W (again since no acceleration)
N= mg - FaSin@

So plugging in,,,
u(mg-Fasin@) = FaCos@

Solving for Fa I got...
umg-uFasin@ = Facos@
Fa= umg/(usin@ + cos@)
Fa= (.33*325 kg*9.8)/(.33sin59.9+cos59.9)
Getting that the force applied = 1335.50 N, but this is not correct.

Any help would be appreciated, thanks in advance.

2. Nov 19, 2016

### TomHart

I found this on a Google search:
In physics, apparent weight is a property of objects that corresponds to how heavy an object is. The apparent weight of an object will differ from the weight of an object whenever the force of gravity acting on the object is not balanced by an equal but opposite normal force.

3. Nov 19, 2016

### anlon

If you assume $apparent \ weight = mg - N$ do you see a way to proceed?

4. Nov 19, 2016

### jmm5180

Yes, thank you!

5. Nov 20, 2016

### Bharat999

Try taking the apparent weight = N.
Given a text passage, determine:
    1. If it contains a mathematical question (including word problems or calculations)
    2. If an answer to that mathematical question is provided in the text

First, describe the content structure you found in 1-2 sentences.

Then provide your analysis in the following format:
TYPE: <one of the following values>
- NO_QUESTION
- SINGLE_QUESTION
- SINGLE_QUESTION_WITH_ANSWER
- MULTIPLE_QUESTIONS
- MULTIPLE_QUESTIONS_WITH_ANSWERS
system
# Homework Help: How much work done by friction when a box w/apparent mass..?

1. Nov 19, 2016

### jmm5180

1. The problem statement, all variables and given/known data
How much work is done by friction when a box with an apparent mass of 325kg moves horizontally across a floor with coefficient of friction of .33 and is pulled at 59.9 degree angle for 2.60 m? What is the force that is pulling the box?

2. Relevant equations
W=Fdcos@ (@= theta)
Fnet=ma

3. The attempt at a solution
I searched for what apparent mass was, but what I found seemed to do with volume and water displacement, which aren't related to this problem. Instead I tried solving the second question first because I needed Normal force to solve the work done by friction.

For my free body diagram, I had force applied (Fa) in the y direction upwards on the y axis along with normal force. Along the negative y axis I had weight. Force of friction (Ff) was along the negative x axis, and force applied in the x direction was on the positive x axis.

In the x direction...
Ff=Facos@ (since no acceleration)
uN = FaCos@

In the y direction...
Fasin@ + N = W (again since no acceleration)
N= mg - FaSin@

So plugging in,,,
u(mg-Fasin@) = FaCos@

Solving for Fa I got...
umg-uFasin@ = Facos@
Fa= umg/(usin@ + cos@)
Fa= (.33*325 kg*9.8)/(.33sin59.9+cos59.9)
Getting that the force applied = 1335.50 N, but this is not correct.

Any help would be appreciated, thanks in advance.

2. Nov 19, 2016

### TomHart

I found this on a Google search:
In physics, apparent weight is a property of objects that corresponds to how heavy an object is. The apparent weight of an object will differ from the weight of an object whenever the force of gravity acting on the object is not balanced by an equal but opposite normal force.

3. Nov 19, 2016

### anlon

If you assume $apparent \ weight = mg - N$ do you see a way to proceed?

4. Nov 19, 2016

### jmm5180

Yes, thank you!

5. Nov 20, 2016

### Bharat999

Try taking the apparent weight = N.
user
The text passage contains a physics problem that involves calculating the work done by friction and the force pulling a box. The problem is presented with a detailed attempt at a solution, and there are responses from other users providing guidance.

TYPE: SINGLE_QUESTION_WITH_ANSWER

However, it's important to note that while the question is asked, the provided solution is not entirely correct according to the user's own statement, and the correct answer is not explicitly given in the text. The user mentions that the force applied they calculated (1335.50 N) is not correct, and they received guidance from other users, but the final correct answer is not stated. Therefore, the answer is partially provided, but not fully resolved in the text. 

Given this, a more precise classification would be:

TYPE: SINGLE_QUESTION