Lesson plan
Jack (device)
using a jack to lift a staff car, January 1945 A jack is a mechanical lifting device. Most often, the term "jack" denotes equipment used to apply great forces or lift heavy loads. There are also smaller, more delicate jacks used as part of the action of keyboard instruments. Of the jacks of the first category (heavy lifting), a mechanical jack employs a screw thread. A hydraulic jack uses hydraulic power. The most common function of a jack is as a car jack, floor jack or garage jack, which lift vehicles so that maintenance can be performed. Jacks are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons). Industrial jacks can be rated for many tons of load.
Article summary
using a jack to lift a staff car, January 1945 A jack is a mechanical lifting device. Most often, the term "jack" denotes equipment used to apply great forces or lift heavy loads. There are also smaller, more delicate jacks used as part of the action of keyboard instruments. Of the jacks of the first category (heavy lifting), a mechanical jack employs a screw thread. A hydraulic jack uses hydraulic power. The most common function of a jack is as a car jack, floor jack or garage jack, which lift vehicles so that maintenance can be performed. Jacks are usually rated for a maximum lifting capacity (for example, 1.5 tons or 3 tons). Industrial jacks can be rated for many tons of load.
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.