Tension on Pulley HW: Block A & B Force Analysis

In summary, the problem involves a setup of two blocks connected by a massless, ideal string and a massless, ideal pulley on a fixed incline. The mass of block A is 2 kg and the mass of block B is 10 kg. The angle of the incline is 41 degrees. To find the tension on the string, one can use the Free Body Diagram of either block A or B, since the tension is the same throughout the string. The acceleration of block B can be found by setting up the equation (x-19.6)/2 = 3.72, where x represents the tension, and solving for x, resulting in a tension of 27.04 N.
  • #1
HydroMarioUSA
10
0

Homework Statement


Block B is positioned on a fixed incline. Attached to block B is a massless, ideal string that runs over a massless ideal pulley and is attached to a hanging block block A at the other end. The mass of block A is 2 kg and the mass of block B is 10 kg. The angle of the incline is 41 degrees.

Homework Equations


(none) Since it never says it's constant velocity we cannot assume Fnet = 0.

The Attempt at a Solution


I drew force diagrams for both A and B, but I don't know how their tensions are related. I'm pretty sure B accelerates towards the left at 3.72 m/s2, since the x component of the force of gravity on B is 64.29, and then you subtract 19.6 from that due to tension, and put that all over 12. But you somehow have to have the tension force on B? And it's not constant velocity? I'm confused...

See screenshot.
 

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  • #2
In general, how would you find the tension on a string if both blocks pull on the string?
 
  • #3
Since the string and pulley are both massless, the string will have the same tension everywhere.

Consider the Free Body Diagram of block A (you could use block B's FBD, too, but block A's is a bit simpler since the slope of the incline is not involved). You have found the acceleration of the block and there are only two forces acting, gravity and the tension.
 
  • #4
Thank you! The answer is C), right? Because you just need to set up the equation (x-19.6)/2 = 3.72, and x = 27.04.
 
  • #5
HydroMarioUSA said:
Thank you! The answer is C), right? Because you just need to set up the equation (x-19.6)/2 = 3.72, and x = 27.04.
Yup!
 

Related to Tension on Pulley HW: Block A & B Force Analysis

1. What is tension on a pulley?

Tension on a pulley refers to the force exerted by a rope or cable that is wrapped around the pulley. It is the force that keeps the pulley in motion and can be calculated by multiplying the mass of the object being lifted by the acceleration due to gravity.

2. How do you calculate the tension on a pulley?

The tension on a pulley can be calculated by using the formula T = m x a, where T is tension, m is mass, and a is acceleration due to gravity. It is important to note that the direction of the tension force will depend on the direction in which the object is being lifted.

3. What factors affect tension on a pulley?

The tension on a pulley can be affected by several factors, including the mass of the object being lifted, the angle of the rope or cable, and the acceleration due to gravity. Other factors such as friction and the shape and size of the pulley may also play a role in determining the tension.

4. How does the tension on a pulley affect the motion of the object?

The tension on a pulley is what keeps the object in motion. If the tension is too low, the object may not be able to move at all. If the tension is too high, the object may move too quickly or even break. The tension on a pulley must be carefully calculated and controlled to ensure the object moves at the desired speed and direction.

5. Can the tension on a pulley be adjusted?

Yes, the tension on a pulley can be adjusted by changing the mass of the object being lifted, the angle of the rope or cable, or the acceleration due to gravity. Additionally, using different materials or sizes for the pulley may also affect the tension. It is important to carefully consider and calculate these factors to achieve the desired tension on a pulley.

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