Figure shows a quick return mechanism. The cranks OA rotates

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Figure shows a quick return mechanism. The cranks OA rotates clockwise uniformly. OA = 2 cm, OO' = 4 cm. The ratio of time for forward motion to that for return motion is

1. 0.5
2. 2.0
3. √2
4. 1

Correct Option: B

Ratio of time of forward motion to return motion

=	180 + 2α	=	180 + 60	=	240	= 2
	180 − 2α		180 − 60		120

(Given OD = 2 cm, OO ' = 4 cm, sin α = 2/4 = 0.5 ⇒ α = 30°)