An toànCâu 453 / 521
A straight or extension ladder should be set at a safe angle by placing its base at what distance from the wall?
a.4 feet out for every 4 feet of height
b.2 feet out for every 4 feet of height
c.3 feet out for every 4 feet of height
d.1 foot out from the wall for every 4 feet of ladder working length (the 4-to-1 rule)
Giải thích
The 4-to-1 rule places the ladder base 1 foot away from the wall for each 4 feet of working length, giving a stable climbing angle of about 75 degrees. Setting it 2, 3, or 4 feet out for every 4 feet of height makes the ladder too flat and likely to slide out at the base.
Trích dẫn luật: Cal/OSHA Title 8 §3276Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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