Force needed to raise a backpack

Thread starter syllll_213
Start date Mar 16, 2025
Tags

Force Work

Click For Summary

The discussion highlights a misunderstanding regarding the diagram depicting a hiker pulling a backpack with a force at an angle to the vertical, which is labeled incorrectly as a vertical force. It questions the relationship between the force exerted by the hiker on the rope and the tension in the lateral section of the rope. Additionally, it points out the oversight of not considering the contribution from the right half of the rope in the analysis. Clarifying these points is essential for accurately understanding the mechanics involved in raising the backpack. Overall, the conversation emphasizes the importance of correctly interpreting forces and tensions in such scenarios.

Mar 16, 2025

syllll_213

Homework Statement: The question is asking how the force needed to raise the pack change, but I am unsure if my working and reasoning is right. Particularly, I am unsure if I can assume both the angles (theta) I labelled to be equivalent because I sort of assumed the force pulled by the guy to be equal to the force pulling on the backpack. Some comment on my working would be appreciated thank you TT.

Relevant Equations: F=ma

Physics news on Phys.org

Mar 16, 2025

haruspex

Science Advisor

Homework Helper

Insights Author

Gold Member

2024 Award

The diagram provided seems to have misled you a little. It shows the hiker pulling down at some angle to the vertical but labels a vertical force ##\vec F##.
How does the force with which the hiker pulls on the rope relate to the tension in the lateral section of the rope?

Also, you seem to have forgotten the contribution from the right half of the rope.

Thread 'Bernoulli vs real life experiment'

If have close pipe system with water inside pressurized at P1= 200 000Pa absolute, density 1000kg/m3, wider pipe diameter=2cm, contraction pipe diameter=1.49cm, that is contraction area ratio A1/A2=1.8 a) If water is stationary(pump OFF) and if I drill a hole anywhere at pipe, water will leak out, because pressure(200kPa) inside is higher than atmospheric pressure (101 325Pa). b)If I turn on pump and water start flowing with with v1=10m/s in A1 wider section, from Bernoulli equation I...

View full post »