- #1
I realized after that! But, I'm still confused on how they got that P =150?TSny said:Note that the equation in the figure is a vector equation:
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The three force vectors add to zero. But you are also correct that the magnitudes of these forces obey -P-W+N = 0.
The μs factor was omitted. It should read 11g=(P+12g)μs.Lori said:I realized after that! But, I'm still confused on how they got that P =150?
I'm still not sure how they calculated P=150 :/ Would appreciate it if anyone explained this one to me because I literally don't know how they added up and got 150. I tried multiplying the static friction tooharuspex said:The μs factor was omitted. It should read 11g=(P+12g)μs.
As haruspex noted, the equation 11g = P + 12g as given in the figure in post #1 is not correct; rather it should be 11g=(P+12g)μs.Lori said:I'm still not sure how they calculated P=150 :/ Would appreciate it if anyone explained this one to me because I literally don't know how they added up and got 150. I tried multiplying the static friction too
Yes, i had trouble with where the equation was coming from, so i just redid it and found the answer myself! let me know if i did it correct cause my physics isn't really strong , so sometimes i doubt myself.!TSny said:As haruspex noted, the equation 11g = P + 12g as given in the figure in post #1 is not correct; rather it should be 11g=(P+12g)μs.
Are you having trouble seeing where this equation comes from, or are you having trouble seeing how to solve this equation for P?
Yes, that's it. Good.Lori said:Nevermind, i worked out the problem and figured thatP + Wb = Fn
Ff = fs*Fn
T=f
T=Wa = 107.8=f
Fn = Ff/fs = 107.8/0.4 = 269.5
P = 269.5 - Wb = 269.5-117.6=251.9 N
Thanks! I fixed it! I was actually wondering how to do that XDTSny said:Yes, that's it. Good.
(You use fs for μs. You can use the formatting toolbar to access Greek letters, subscripts, etc. Click on the symbol Σ at then end of the toolbar to access Greek letters and other math symbols.)
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A pulley problem with external force is a type of physics problem that involves a system of pulleys and an external force acting on the system. The goal of these problems is to determine the tension and/or motion of the objects involved in the system.
The key components of a pulley problem with external force are the pulleys themselves, the objects attached to the pulleys, and the external force acting on the system. These components are used to calculate the tension and motion of the objects in the system.
To solve a pulley problem with external force, you first need to identify all of the forces acting on the objects in the system. Then, you can use Newton's laws of motion and the principles of static equilibrium to set up and solve equations to determine the tension and motion of the objects.
One common mistake when solving a pulley problem with external force is not considering all of the forces acting on the system, including the weight of the pulleys themselves. Another mistake is not correctly setting up and balancing the equations, which can lead to incorrect solutions.
Pulley problems with external force have many real-world applications, such as in engineering and construction projects that involve lifting and moving heavy objects. They are also used in the design of pulley systems for elevators and cranes, and in the study of mechanics and physics.