Is this Free-Body Diagram Correct?

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DevonR
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Homework Statement


I have to draw a free body diagram representing the motion of an object @ a given point in time. This diagram is for section 1.

It's of a 1.25 kg cart with a 0.6 kg can attached to it with a pulley-system. When the can drops, the cart begins to move. In section one, when the can drops, the cart begins to accelerate forward.

Acceleration = 0.196 m/s(squared)
Mass of cart = 1.25 kg
Mass of can = 0.6 kg

Homework Equations

F = ma

The Attempt at a Solution



The diagram is uploaded here. I just want to know if this seems to be correct?

EDIT:

Heres the assmuptions I made

I calculated net force w/ acceleration provided = 0.196 m/s
and with the total mass (1.25 kg + 0.6 kg) = 1.9 kg
Net force = 0.37 N

I did normal force & force of gravity on the cart, which was 12.3 N for both.
The falling can was what caused the motion of the cart, so I calculated Fg = 5.9 N for the 0.6 kg can. No normal force obviously because it wasn't sitting on a surface.

But the can was attached to a string, which slowed down the falling can's motion. So I had to calculate F-tension. I used this formula to calculate it;

Force of Tension = 2m1m2/m1m2 x Gravity

I got 4N (3.97N) as the tension force.

So I assumed that the applied force would be Force of Gravity on the can MINUS the Force of Tension of the string holding the can. The applied force was 1.9 N

Then I calculated force of friction.
I assumed it to be the applied force minus net force
Which was 1.9 N - 0.37 N

For friction I got 1.5 N.

Does all of this seem correct? [/B]


freebody.jpg
 

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Thanks for the reply! I added a written description of my 'attempt @ a solution' to the original post.
I see what you mean, so I should draw Fa = 1.9 horizontally.

Aside from that, is everything else okay?
 
haruspex said:
How did you get that? Without the tension, the acceleration would be g. So what tension is required to reduce it to the given acceleration?

I used this formula Force of Tension = 2m1m2/m1m2 x Gravity
to get the force of tension


 
DevonR said:
I got the formula from here

http://www.citycollegiate.com/tension1.htm
Two problems:
- you omitted the plus signs, minus signs and parentheses, making it impossible to decipher.
- it doesn't apply in your set up; compare the diagrams
It's quite easy from first principles without searching for answers on the net. Just consider the FBD of the hanging mass.