Consider two rods forming V-shape with angle θ and a ball, of radius r, mass m, and moment inertia I, on it. See picture below.
The ball is released at position l from rods' adjacent and start moving because of gravitational acceleration, g. The rods are rough enough, so it prevents the ball from slipping in its movement.
Calculate the initial angular acceleration of the ball!

Click here to read the solution.

V-shaped Rod PathSocialTwist Tell-a-Friend


Anonymous said... @ February 18, 2009 at 1:21 PM

I am not able to feel how this ball will rotate...some prob is there . I guess direction of g will be parallel to plane of the rods ....
Please help me . and if possible provide solutions for all the questions.sometimes Its really difficult to solve.

Copycat91 said... @ February 18, 2009 at 4:22 PM

You can try it at your home, use two identical pens (or pencils) and one small ball, and arrange it like shown above.

g is perpendicular to plane of the rods. The rods are lied on xz-plane, and g is parallel to y-axis.

Sorry, I forgot linking it to the solution..

Anonymous said... @ February 18, 2009 at 5:41 PM

hey thnx for ur suggestion .... I was not able to visualise that one component of normal reaction will come in the direction of opening rod ...that why i was thinking that there is no tendency of motion. so friction wont act .... now after seeing the diagram given in solution it is clear to me :) . Thanks for ur valuable effort to clarify my doubt.

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