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Phy 201
Your 'question form' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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An applied force of 6 Newtons acts in the direction of motion of a block of mass 9 Kg, with the mass being pulled across the floor against a frictional force of .6 Newtons.
What is the net force on the object?
How much work does the net force do on the object?
How much work does the applied force do on the object?
What is the work done by the frictional force on the object?
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I understand how to achieve net force. But if work is the amount of force over a distance, I am not sure of how to accomplish this because we are not given a distance.
A displacement should have been given. In a case like this you could just write your solution in terms of the symbol `ds (e.g., frictional force does work -.6 N * `ds, applied force does work 6 N * `ds). However when a problem on a test is not properly posed, it counts only if it helps your grade.
Another question: when given a statement such as 8 degrees with horizontal is this the exact angle? We need to do nothing else do it except use it to solve the problems?
You sometimes need to use a given angle to find other angles. For example an incline at 8 degrees with horizontal implies a weight vector at 262 deg or 278 deg relative to the x axis of your rotated x-y coordinate plane. Whether 262 deg or 278 deg depends on how you sketch the incline.
Is the velocity associated with KE=0.5m v^2, average velocity?
Your context here isn't clear.
The average value of v^2 is not the square of the average value of v.
For example if velocities are 3, 5 and 7 cm/s, their average is 5 cm/s. The squared velocities are 9, 25 and 49 cm^2/s^2. If you average these squared velocities you get almost 28 cm^2 / s^2. However the square of the average velocity 5 cm/s is 25 cm^2 / s^2.
I'm not sure this addresses your questions.
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Thanks again! More questions may follow....and just so you know your instructions are not lost, I have spent a good portion of my physics alloted time on reviewing Intro Sets!
I'll be interested in your opinion of the value of the intro problem sets.
See my answers to your questions.
#$&*
Phy 201
Your 'question form' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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Below is a sample problem from the test and I am fairly certain I got it right, do you care to check over it? Thanks!
Problem Number 3
An Atwood machine consists of 33 paper clips, each of mass .8 grams, suspended from each side of a light pulley.
• If 3 clips are transferred from one side to the other, what will be the total gravitational on the system?
• If the frictional force exerted by the pulley is .026 times the total weight of the system, then what is the net accelerating force?
• What therefore is the acceleration of the system?
*****Total gravitational on the system is 4707 g cm/s^2 after finding the wt on each side of the pulley to me 28224 g cm/s^2 and 23520 g cm/s^2 and finding the difference. The Ffriction is 51744g cm/s^2*.026=1345.3 g cm/s^2. The accelerating force would be 3359 g cm/s^2. The acceleration would be 3359 g cm/s^2/52.8 g(total mass)=63.6 cm/s^2.
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your solution looks great.