Chapter 9, Problem 15Q

To determine

Which configuration of bricks is the more likely to be stable? Why?

Answer to Problem 15Q

Solution:

Configuration of figure 2 is more stable because net torque is zero.

Explanation of Solution

Compare figures 1 and 2; configuration of the figure 2 is more stable. This is because the CG of the system on figure 2 is just above the pivot point, this means that the weight of the system passes through the pivot and therefore the net torque is zero. Instead, the CG on figure 1 is more displaced to the right and therefore the weight of the system makes a clockwise torque which implies that the system is more unstable. Therefore, the system of bricks of configuration in Fig. 2 is more stable.