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Grade 11Mechanics

The end `A` of a uniform rod AB of length `l` touches a horizontal smooth fixed surface. Initially makes an angle of 30° with the vertical. Find the magnitude of displacement of the end B just before it touches the ground after the rod is released.

Profile image of Mohit Soni
8 Years agoGrade 11
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1 Answer

Profile image of Shirish Shrivastav
8 Years ago
When rod is released it falls due to gravity so no external force acts along horizontal direction so center of mass will not displace along horizontal. Initial horizontal distance of B from C. O. M is l/2sin30Final horizontal distance of B from C is l/2.There fore horizontal displacement of B is l/2 - l/4= l/4Vertical displacement of B is l cos 30Write displacement of B in vector form, -l/4 i - root 3/2 l j and find its magnitude. Answer is root 13 l/4