Angular Momentum and Torque of a Moving Particle

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SUMMARY

The discussion focuses on calculating the angular momentum and torque of a 2.9-kg particle located at coordinates (3.3 m, 1.8 m) and moving with a velocity of (-4.1 m/s, 2.6 m/s). The relevant equations used are L = r x mv for angular momentum and T = r x F for torque. The participant initially struggled with determining the direction and magnitude using the cross product method but later clarified their approach and successfully solved the problem. This highlights the importance of considering vector directions and angles in calculations.

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  • Understanding of vector operations, specifically cross products
  • Familiarity with angular momentum and torque concepts
  • Knowledge of Newton's laws of motion
  • Basic proficiency in physics equations related to motion
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  • Study the properties of cross products in vector mathematics
  • Learn about angular momentum conservation in closed systems
  • Explore torque calculations in different coordinate systems
  • Review examples of force applications in rotational dynamics
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agargento
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Homework Statement



A 2.9-kg particle P is located at [(r)\vec] = 3.3 m [^(x)] + 1.8 m [^(y)] from the origin of the x-y coordinate system shown in the Figure. It moves with a velocity of [(v)\vec] = −4.1 m/s [^(x)] + 2.6 m/s [^(y)]. A force, [(F)\vec] = 2.7 N [^(x)] + 1.4 N [^(y)] acts on the particle.

a) What is the magnitude and direction of the angular momentum of the particle with respect to the origin of the coordinate system?
b) What is the magnitude and direction of the torque acting on the particle with respect to the origin of the coordinate system?

‏‏לכידה.PNG


Homework Equations



L = r x mv
T = r x F

The Attempt at a Solution



At first I tried to take the magnitude of the radius r, the mangitude of v, and multiply by the mass. But this doesn't give me the direction... I also tried taking the cross product but it didn't go well, I got confused with the direction and the multiplication... would love some guidance.

Edit: Got the answer. Sorry for littering the forum ;)
 
Last edited:
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agargento said:
At first I tried to take the magnitude of the radius r, the mangitude of v, and multiply by the mass. But this doesn't give me the direction...
It also won't give you the correct magnitude if you ignored the angle between the vectors...
agargento said:
I also tried taking the cross product but it didn't go well, I got confused with the direction and the multiplication...
Show the details of your attempt using the cross product method. We can't critique what we can't see :smile:
 

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