Motion in 2 Dimensions - Pulleys

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SUMMARY

The discussion centers on calculating the acceleration, tension, net force, and kinetic energy of two connected masses (1.6kg and 2.4kg) using a frictionless pulley system. Key equations include Newton's second law and kinematic equations. Users emphasize the importance of drawing free body diagrams to analyze forces acting on each mass. The correct acceleration is determined to be 1.6 m/s², and it is clarified that this value is not to be confused with velocity.

PREREQUISITES
  • Understanding of Newton's second law (F=ma)
  • Familiarity with kinematic equations (e.g., v² = u² + 2as)
  • Ability to draw and interpret free body diagrams
  • Basic knowledge of gravitational force (9.8 m/s²)
NEXT STEPS
  • Study how to derive acceleration in pulley systems using free body diagrams
  • Learn about tension in strings and its calculation in connected mass problems
  • Explore the concept of net force and how it applies to multiple masses
  • Investigate kinetic energy calculations in dynamic systems
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and dynamics, as well as educators looking for problem-solving strategies in pulley systems.

TheKovac
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Homework Statement


Two masses A and B and of mass 1.6kg and 2.4kg respectively are connected be a light string which passes over a a frictionless trolley.
Calculate:
a) The accelaration of the 1.6kg mass.
b) The tension in the string
c) The net force on the 2.4kg mass
d) The Kinetic Energy of the 1.6kg Mass 0.5s the two masses are released.

Homework Equations


P=MV - M yes, V no, P no
u= v+at
v^2 = U^2 + 2as

The Attempt at a Solution


On first glance, it seems there is not enough data to be able to work out Acceleration. Am I right?

I request that some helpful user will be able to show a way to work the problem out, with the given data, and how Tension can be calculated. I am not asking that someone will do my homework, just that someone will help me work acceleration because I don't think there's enough data

Thank you in Advance.

Kindest Regards,
The Kovac
 
Last edited:
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Yes there is sufficient info I believe.

Start with drawing a free body diagram.

What are the forces acting on the 1.6kg mass? Similarly, what are the forces on the 2.4kg mass?

Assume the motion is downward with respect to the 2.4kg mass (meaning the 2.4kg mass moves down). ( Both would accelerate at the same rate so...)

What is the equation relating the resultant force for the 2.4kg mass?
What is the equation relating the resultant force for the 1.6kg mass?

If you did it correctly, you should see a way to get the acceleration and tension.
 
draw free body dig.and use
net f(on a body)=ma(of that body).
 
IS not the acceleration Zero? The question does not mention any details regarding any movement, so there has to be no acceleration, no?

If there is acceleration, would not that be 9.8m/s due to gravity? The answer is 1.6m/s but little data a figure such as that I am struggling to find.

Thank you for the assistance.
 
The acceleration would not be that of gravity, as there are other forces you must take into consideration. Also, there is an acceleration.
 
Also, I would hope the answer for acceleration is not 1.6 m/s; that is velocity.
 

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