Physics problem finding tension of a string

AI Thread Summary
The discussion revolves around calculating the tension in a string connecting two blocks with different masses on inclined and horizontal surfaces. The user initially calculated a tension of 4.7 N but questioned its validity since it was smaller than the normal force. Participants suggest using a combination of equations to solve for tension, emphasizing the need to consider both blocks' dynamics. The importance of understanding the relationship between tension and normal force is highlighted, with clarification that tension does not need to exceed the normal force. The conversation aims to refine the approach to accurately determine the tension in the string.
nothingatall
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Homework Statement



In Fig. 6-50, block 1 of mass 1.3 kg and block 2 of mass 2.5 kg are connected by a string of negligible mass and are initially held in place. Block 2 is on a frictionless surface tilted at θ = 31o. The coefficient of kinetic friction between block 1 and the horizontal surface is 0.16. The pulley has negligible mass and friction. Once they are released, the blocks move. What then is the tension in the string?


Homework Equations


Maybe T-muFN=m1a
Fn=m1a=12.74
Combined equation: T=-m2a+m2gsin(theta)


The Attempt at a Solution


My T came out to be 4.7N but since it is smaller than my Fn I know it can't be correct.
What equation will give me the correct answer?
 
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nothingatall said:

Homework Statement



In Fig. 6-50, block 1 of mass 1.3 kg and block 2 of mass 2.5 kg are connected by a string of negligible mass and are initially held in place. Block 2 is on a frictionless surface tilted at θ = 31o. The coefficient of kinetic friction between block 1 and the horizontal surface is 0.16. The pulley has negligible mass and friction. Once they are released, the blocks move. What then is the tension in the string?


Homework Equations


Maybe T-muFN=m1a
Yes, for the block on the horizontal surface
Fn=m1a=12.74
Yes, for the block on the horizontal surface, where a = g in this case.
Combined equation: T=-m2a+m2gsin(theta)
This is the equation for the block on the incline. It is not a combined equation. Use this equation in combination with your first 2 equations to solve for the tension.

The Attempt at a Solution


My T came out to be 4.7N but since it is smaller than my Fn I know it can't be correct.
What equation will give me the correct answer?
Mt T comes out slightly larger, but why do you think T needs to be greater than Fn?
 
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