Chapter 9, Problem 4P

What is the mass of the diver in Fig. 9-49 if she exerts a torque of 1800m. N on the board, relative the left (A) support post?

To determine

Mass of the diver relative to left post support.

Answer to Problem 4P

Solution:45.91 kg

Explanation of Solution

Given: Diver exerts torque = 1800 m-N

Formula Used:

Torque:

  $\tau =F\times r=\text{(}ma\text{)}\times \text{(}r\text{)}$

Here, F is the exerted force and r is the distance from the rotational axis.

Calculation:

Torque about A:

  $\begin{array}{l}\tau =\text{(4m)(mg)}\text{=}\text{1800 m }\cdot \text{N}\\ \Rightarrow \text{m = }\frac{\text{1800 m}\cdot \text{N}}{4\text{m}\times 9.8\text{m}\cdot {\text{s}}^{-2}}\\ \Rightarrow \text{m = 45}\text{.91 kg}\end{array}$

Conclusion:

Mass of the diver is 45.91 kg relative to left post support (A).