Solving a Tension Problem with 9 kg Handing Weight & 5 kg Block

  • Thread starter Thread starter tristan_fc
  • Start date Start date
  • Tags Tags
    Tension
AI Thread Summary
The discussion revolves around solving a tension problem involving a 9 kg hanging weight and a 5 kg block on a table, with a coefficient of kinetic friction of 0.187. The original poster is confused about how to calculate the tension in the string, mistakenly believing that friction increases tension. However, it is clarified that if there were no friction, the block would move freely, resulting in no tension in the rope. The correct understanding is that the tension in the rope is equal to the friction force opposing the motion of the block. The conversation emphasizes the importance of accurately accounting for forces in tension problems.
tristan_fc
Messages
12
Reaction score
0
I believe that I was late the day my instructor explained this type of problem in class, and my textbook is worthless, so I thought I would give this a shot. It's just a tension problem, but I don't know for sure how to do it.

A 9.00 kg handing weight is connected by a string over a pulley to a 5.00 kg block that is sliding on a flat table. If the coefficient of kinetic friction is 0.187, find the tension in the string.

I believe that tension is the sum of all forces on the rope correct? I recall my teacher saying that we could turn a similar problem into a problem on the X-axis by making gravity a force pulling on the block in the x-direction. Anyway, I thought that I would just do 9*9.8+-(5*0.187), but that didn't seem right to me because it would seem that a frictional force would increase the tension and not decrease it? I appreciate any help.

-Tristan
 
Physics news on Phys.org
eh... I posted my question in the wrong section and they moved it here. I'm actually in Engineering Physics I in college, but I guess it doesn't matter where the question is if I get help.
 
Yes, frictional force would increase tension, not decrease it.
However, if there were NO friction force, there would be NO tension on the rope, not the "9*9.9" you have. If there were no friction force the block would move freely. The tension on the rope IS the friction force.
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanged mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top