Question:

What is the mass of the diver in Fig. 9–49 if she exerts a torque of $1800 \textrm{ m}\cdot\textrm{N}$ on the board, relative to the left (A) support post?

Figure 9-49.

Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.

Quick Answer:

$46\textrm{ kg}$

### Transcript for this Giancoli solution

This is Giancoli Answers with Mr. Dychko. The torque exerted by this diver about support post A is gonna be the diver's weight*mg*multiplied by their distance to the support A which I have labeled

*l*subscript

*D*for the lever arm of the diver. And we can solve for mass by dividing both sides by

*gl D*and so that mass is gonna be torque divided by

*gl D*and that's 1800 newton meters divided by 9.8 newtons per kilogram times 3.0 meters plus 1.0 meter so that's a total of 4.0 meters away from between the support post and the diver and that gives about 46 kilograms.