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When tightening a bolt, you push perpendicularly on a wrench with a force of 165 N at a distance of 0.140 m from the center of the bolt. (a) How much torque are you exerting in newton × meters (relative to the center of the bolt)? (b) Convert this torque to footpounds.
Question by OpenStax is licensed under CC BY 4.0.
  1. $23.1 \textrm{ N}\cdot\textrm{m}$
  2. $17.0 \textrm{ ft}\cdot\textrm{lbs}$

Note: The video incorrectly shows the conversion to $\textrm{ft}\cdot\textrm{lbs}$ by dividing instead of multiplying by 0.7356. The calculator screenshot has been corrected, and the final answer above is correct.

Solution Video

OpenStax College Physics Solution, Chapter 9, Problem 2 (Problems & Exercises) (0:34)

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Calculator Screenshots

OpenStax College Physics, Chapter 9, Problem 2 (PE) calculator screenshot 1
Video Transcript

This is College Physics Answers with Shaun Dychko. We are going to calculate the torque applied about the bolt when applying a force of 165 newtons on the wrench at a distance that's perpendicular to the pivot, 0.140 meters away. So we multiply these two together and get 23.1 newton meters and converting that into foot pounds by multiplying by 1 ft lbs for every 0.73756 newton meters, this is 31.3 ft lbs.


Submitted by NoOneReally on Tue, 06/02/2020 - 22:29

You inverted the conversion factor in Part B. 1 Newton meter =.73756ftlbs; your final answer should be 17.0ftlbs, not 31.

Submitted by ShaunDychko on Wed, 06/03/2020 - 13:13

Thank you very much for pointing this out SomeOneReally :) I've corrected the final answer, the calculator screenshot, and made a note below the final answer. The video is flagged for correction later.

In reply to by NoOneReally