Activity 2.1.5 Calculating Moments
Introduction
Why would the Leaning Tower of Pisa be more likely to fall over with a group of people on the top floor rather than the bottom floor? The people weigh no more or less on one floor than the other. This is because the tower is anchored at the bottom. If the tower fell, the top would rotate around the base where it is pivoted. As more weight gathers at the top of the tower, a greater tendency to rotate exists because the weight has shifted further from the base. Such force is referred to as a moment. Engineers must be able to understand and calculate moments. Sometimes they need large moments to perform work, but they also must account for all moments inherent in any system in order to be sure that the design is safe and functions as intended.
Why would the Leaning Tower of Pisa be more likely to fall over with a group of people on the top floor rather than the bottom floor? The people weigh no more or less on one floor than the other. This is because the tower is anchored at the bottom. If the tower fell, the top would rotate around the base where it is pivoted. As more weight gathers at the top of the tower, a greater tendency to rotate exists because the weight has shifted further from the base. Such force is referred to as a moment. Engineers must be able to understand and calculate moments. Sometimes they need large moments to perform work, but they also must account for all moments inherent in any system in order to be sure that the design is safe and functions as intended.
Conclusion
1. Calculate the moment if you were to hold a 15 lb bowling ball with your arm straight out and your forearm perpendicular to your body. What is the pinned connection?
M: FxD; M: (15lb) x (Length of my arm)
2. Why are clockwise moments considered negative when they are summed with counterclockwise moments?
Clockwise moments are considered negative when summed with counterclockwise moments because they are opposites of each other, but also because counterclockwise moments are positive since when acting upon an object, they move the object up on the Y-Axis.
1. Calculate the moment if you were to hold a 15 lb bowling ball with your arm straight out and your forearm perpendicular to your body. What is the pinned connection?
M: FxD; M: (15lb) x (Length of my arm)
2. Why are clockwise moments considered negative when they are summed with counterclockwise moments?
Clockwise moments are considered negative when summed with counterclockwise moments because they are opposites of each other, but also because counterclockwise moments are positive since when acting upon an object, they move the object up on the Y-Axis.