• Post a New Question
• Current Questions
• Chat With Live Tutors

Homework Help: physics

Posted by Samuel on Monday, October 13, 2008 at 2:28am.

An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm is 75.0 cm long and has a mass of 5.28 kg. What is the magnitude of the torque about his shoulder if he holds his arm straight out to his side, parallel to the floor?


Responses


Physics - bobpursley, Saturday, October 11, 2008 at 9:36pm
The torque has to be the weight of the ball x distance plus the weight of the arm x 1/2 the length of the arm(assuming the cg is at the midpoint).

Is distance 0.75 m?


Responses


physics - drwls, Sunday, October 12, 2008 at 11:35am
What distance? The arm length is 0.75 m, but half of that is 0.375 m

If you want torque in units of Newton-meters, the lengths must be in meters when you do the calculation

---------------------
Torque = the weight of the ball x distance plus the weight of the arm x 1/2 the length of the arm

= 4.33 kg x 0.75 m + 5.28 kg x 0.375 m
= 3.2475 + 1.98
= 5.23 N

What am I doing wrong?

• physics - drwls, Monday, October 13, 2008 at 2:37am

  Torque is not measured in Newtons. You failed to include g as a factor to convert mass to weight.
  

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Physics - An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 5.29 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 1.2 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 1.2 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm ...
physics - An athlete at the gym holds a 4.33 kg steel ball in his hand. His arm ...
Physics!! - An athlete at the gym holds a 5.54kg steel ball in his hand. His arm...

For Further Reading