Structures and Forces: Going Further
Loads, stress and failure, worked out rather than described.
8 questions, free, marked as you go with a worked explanation on every one.
What this covers
- structures and forces
The questions
- A footbridge deck has a mass of 1800 kg and must also carry up to 25 people of 70 kg each. What is the total load in kilograms that the supports must carry?
- A shelf sags in the middle under a row of books. Which describes what the material is doing at the top and bottom of the shelf?
- Which of these make a structure stiffer without adding much mass? Select all that apply.
- A column has a cross-sectional area of 0.05 square metres and carries a load of 12000 newtons. What is the stress on the column, in newtons per square metre?
- Why is a triangle used so heavily in bridge trusses, while a plain rectangle is not?
- A student tests two paper columns of the same mass: one rolled into a cylinder, one folded into a flat strip. The cylinder holds far more books. Why?
- A crane's cable is rated to hold 8000 N safely. Engineers apply a safety factor of 5, meaning the cable is built to withstand five times the rated load before breaking. At what force, in newtons, is the cable expected to break?
- A tall structure is more likely to topple in wind than a short one of the same mass. Which explanation is best?