Help with Tension Problems

  • #1
Hi! The following 2 questions I have for homework for this week, and I'm stuck on the steps I need to approach this types of questions.
If someone could provide a brief analysis or suggestions as to how to go about problems involving tensions, that would be very helpful.

1) If M=1.1kg, what is the tension in the string 1?

2) Two objects are connected by a light string that passes over a frictionless pulley. Draw a Free Body Diagram of both objects. If the inclide is frictionless and if m1= 2kg, m2=6kg and angle theta=55 degrees, find:
(a) the accelerations of the objects
(b) the tension in the string
(c) the speed of each object 2 sec after being released from rest.

ANY feedback about analysing tension questions such as the ones mentioned above would terrific. Physics is really not my strong point. In a free body diagram in #2, what forces are acting on the objects being pullied? Gravity? Normal?
 

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Answers and Replies

  • #2
Tom Mattson
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physixnot4me said:
ANY feedback about analysing tension questions such as the ones mentioned above would terrific.

You would follow the same procedure for both of them.

* Identify the forces acting on the object in question.
* Draw a free body diagram showing only the forces (no cables or inclined planes or anything else)
* Sum the forces and apply Newton's second law: [itex]\Sigma\vec{F}=m\vec{a}[/itex]

In a free body diagram in #2,

I wouldn't call that a free body diagram, because it shows the physical apparatus and not the force vectors.

what forces are acting on the objects being pullied? Gravity? Normal?

Yes, both of those are acting, but that's not all. There's also a rope attached to that object, and a force is transmitted through it.
 
  • #3
tension in first string is MG = 1.1x9.8=10.78N
 

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