How Do You Calculate Work and Force for a Displaced Mail Bag?

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SUMMARY

The discussion focuses on calculating the horizontal force and work done on a displaced mail bag with a mass of 140 kg, suspended by a vertical rope of 8.00 m. The correct tension in the rope is 1272 N, and the angle from the vertical is 22 degrees. The user initially miscalculated the horizontal force, which should be derived from the tension and the angle, leading to the need for accurate trigonometric application in the calculations.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Basic trigonometry, specifically sine and cosine functions
  • Knowledge of work-energy principles
  • Familiarity with tension in ropes and forces in equilibrium
NEXT STEPS
  • Calculate horizontal force using the formula: F_horizontal = Tension * sin(angle)
  • Determine work done using the formula: Work = Force * distance * cos(angle)
  • Explore Mastering Physics resources for similar problems
  • Review concepts of static equilibrium in physics
USEFUL FOR

Students studying physics, particularly those tackling problems related to forces, work, and energy in mechanics. This discussion is beneficial for anyone preparing for exams or assignments in physics courses.

melodrameric
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Hi there, I'm new here, and I desperately need help with this work/energy business. Here's my problem:

A mail bag with a mass of 140 kg is suspended by a vertical rope of length 8.00 m.
a) What horizontal force is necessary to hold the bag in a position displaced sideways a distance 3.00 m from its initial position?
b) How much work is done by the worker in moving the bag to this position?

I know that the angle from the vertical will be 22 degrees, and that the tension in the rope will be 1272 N (or am I wrong?), but I don't know where to go from there.

By the way, this is for a Mastering Physics problem, and I've already found out that 476.5 N [1272*cos(68)]is a wrong answer.

Thank you!
 
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You got the tension wrong, that's all. It looks like your method is OK.
 

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