IF F=MGcos θ AND THE ANGLE BETWEEN F AND D IS θ
THEN WILL THE WORK BE MGcos2θ?
MGDcos²θ, yes. But I'm a bit concerned about your formulas to begin with. What's the setup? You might be accounting for θ once more than you need to.
serway problem 7,20
I'm not sure why you assume we all have access to every textbook used for physics lectures.
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