Question

Explain the whole concept that when is W = F * cos theta * s

Answer 1

Answer:

(a) i . i = (1)(1) cos 00 = 1

(b) i . j = j . i = (1)(1) cos 900 = 0

(c) j . j = (1)(1) cos 00 = 1

(d) W = F . s = 20 N j . 4 m i = 80 J(j . i) = 0

(e) W = F . s = (3i + 4j)N . (2i - 2j)m = 6J(i . i) - 6J(i . j) + 8J(j . i) - 8J(j . j)

= 6 J - 0 + 0 - 8 J = -2 J

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