Examkin

Question

Difficulty: EasyLoad Distribution and Balancing

Three identical 1010-foot planks are each placed across two sawhorses, one sawhorse at the left end (Support X) and one at the right end (Support Y). A single 6060-pound bag of cement is placed on each plank at a different location. Rank the scenarios below based on the amount of downward force carried by Support X, from greatest to least.

  1. 1The bag of cement is placed 33 feet from Support X.
  2. 2The bag of cement is placed exactly in the middle of the plank.
  3. 3The bag of cement is placed 22 feet from Support Y.

Answer

The bag closest to Support X places the greatest load on it, followed by the centered bag, while the bag closest to Support Y places the least load on Support X.
Support X must carry the largest portion of the load when the weight is closest to it. As the weight moves further away across the plank, the amount of force supported by X decreases.

Step-by-Step Solution

1
Understand the principle of load distribution.
The closer a weight is to a given support, the more of that weight the support must carry.
This is a basic rule of mechanical balance and levers.
2
Evaluate the load on Support X for the bag placed 33 feet from it.
This bag is very close to Support X, so Support X carries more than half the weight.
The distance to X is smaller than the distance to Y.
3
Evaluate the load on Support X for the centered bag.
This bag is exactly 55 feet from both supports, so Support X carries exactly half the weight.
A centered load is shared evenly.
4
Evaluate the load on Support X for the bag placed 22 feet from Support Y.
This bag is 88 feet away from Support X, so Support Y carries almost all the weight, leaving very little for Support X.
The distance to X is much larger than the distance to Y.

Key Concept

The proportion of a load carried by a support increases as the center of gravity moves closer to that support.
Rate this question

Topics

Load Distribution and Balancing

More questions from this topic