Question 130: Laws of Motion

Question

Two forces P and Q, of magnitude 2F and 3F, respectively, are at an angle $$	heta $$ with each other. If the force Q is doubled, then their resultant also gets doubled. Then, the angle $$	heta $$ is -

Accepted Answer

4F
2
+ 9F
2
+ 12F
2
cos $$	heta $$ = R
2
4F
2
+ 36F
2
+ 24F
2
cos $$	heta $$ = 4R
2
4F
2
+ 36F
2
+ 24F
2
cos $$	heta $$
= 4(13F
2
+ 12F
2
cos$$	heta $$) = 52F
2
+ 48F
2
cos$$	heta $$
cos $$	heta $$  =  $$-$$ $${{12{F^2}} \over {24{F^2}}}$$ = $$-$$ $${1 \over 2}$$

Answer

90o

Answer

60o

Answer

30o

Answer

120o

Laws of Motion

Two forces P and Q, of magnitude 2F and 3F, respectively, are at an angle $\theta with each other. If the force Q is doubled, then their resultant also gets doubled. Then, the angle \theta $ is -

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