Calculating Force Needed to Lift 79kg Mass at Const. Speed

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SUMMARY

The discussion focuses on calculating the force required to lift a 79 kg mass at a constant speed. The gravitational force acting on the mass is determined using the equation Fg = mg, resulting in a force of 774.2 N. To maintain constant speed, the upward force (Fp) must equal the gravitational force, leading to the conclusion that the woman must pull with a force of 774.2 N. Understanding the mechanics of the lifting process, such as the use of a rope and pulley, is essential for a complete analysis.

PREREQUISITES
  • Understanding of Newton's Second Law (ΣF = ma)
  • Basic knowledge of gravitational force calculations (Fg = mg)
  • Familiarity with concepts of force equilibrium
  • Ability to interpret simple mechanical systems (e.g., rope and pulley)
NEXT STEPS
  • Study the principles of force equilibrium in static and dynamic systems
  • Learn about the mechanics of pulleys and their applications in lifting
  • Explore advanced topics in Newtonian physics, focusing on forces and motion
  • Investigate real-world applications of force calculations in engineering
USEFUL FOR

Physics students, mechanical engineers, and anyone interested in understanding the principles of force and motion in practical scenarios.

daltomagne
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A woman raises herself in a bucket. How hard must she pull downward to raise herself slowly at constant speed? The mass of the person plus the bucket is 79 kg.

m=79kg
g=9.8m/s^2 (downward)

i know \SigmaF=ma so i end up with 774.2 N. I'm a little lost as where to go now.
 
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Sum the forces in the y direction, if speed is constant that acceleration is zero

Forces in y =Fp- Fg = 0

Solve for fp
 
You actually already solved it. For something to move at a constant speed, the net force has to be 0. So she just has to pull hard enough to overcome the gravitational force. Which you already calculated.
 
You need to understand how she is raising herself. A simple rope and pulley arrangement? A diagram would be helpful.
 

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