Question
Question: A hollow cylinder of radius 4R is rotating about fixed horizontal axis passing through point 'O' wit...
A hollow cylinder of radius 4R is rotating about fixed horizontal axis passing through point 'O' with angular velocity ω0. A solid cylinder of radius 'R' is rolling without slipping with respect to inner surface of hollow cylinder. At the given instant, the line OC has angular velocity of 2ω0. Point A and B are topmost and bottom most point of solid cylinder respectively and C is its centre. Then, at the given instant
Angular velocity of solid cylinder about its own axis is 10ω0
Magnitude of acceleration of point A of solid cylinder is 88ω02R
Magnitude of acceleration of point B of solid cylinder with respect to contact surface of hollow cylinder is 112ω02R
Radius of curvature of point A is 1132R
Magnitude of acceleration of point A of solid cylinder is 88ω02R
Solution
Let Rh=4R be the radius of the hollow cylinder and Rs=R be the radius of the solid cylinder. The hollow cylinder rotates about O with angular velocity ωh=−ω0k^ (clockwise). The line OC rotates about O with angular velocity ωOC=−2ω0k^ (clockwise). The distance OC is Rh−Rs=4R−R=3R. At the given instant, C is at (0,−3R). The velocity of the center of the solid cylinder C is vC=ωOC×rC=(−2ω0k^)×(−3Rj^)=−6ω0Ri^.
Let ωs be the angular velocity of the solid cylinder about its own axis C. The point of contact P is the bottommost point of the solid cylinder, so rCP=−Rj^. The velocity of the point P on the solid cylinder is vP=vC+ωs×rCP. The point of contact P on the hollow cylinder is on the inner surface at a distance 4R from O, so rOP=−4Rj^. The velocity of the point P on the hollow cylinder is vP′=ωh×rOP=(−ω0k^)×(−4Rj^)=−4ω0Ri^. Since there is no slipping, vP=vP′. vC+ωs×rCP=vP′. −6ω0Ri^+ωs×(−Rj^)=−4ω0Ri^. ωs×(−Rj^)=2ω0Ri^. Let ωs=ωsk^. Then (ωsk^)×(−Rj^)=Rωsi^. Rωsi^=2ω0Ri^, so ωs=2ω0. The angular velocity of the solid cylinder about its own axis is ωs=2ω0k^ (counter-clockwise). Option (A) is incorrect.
Let's find the acceleration of C. vC=−6ω0Ri^. aC=dtdvC. The velocity vC is given by the rotation of rC about O with angular velocity ωOC. aC=αOC×rC+ωOC×(ωOC×rC). Assuming ωOC=2ω0 is constant, αOC=0. aC=ωOC×vC=(−2ω0k^)×(−6ω0Ri^)=12ω02R(k^×i^)=12ω02Rj^.
Let's find the angular acceleration of the solid cylinder. The no-slip condition is vC+ωs×rCP=vP′. Differentiating with respect to time: aC+αs×rCP+ωs×vP/C=aP′. vP/C=ωs×rCP=(2ω0k^)×(−Rj^)=2ω0Ri^. aP′ is the acceleration of the point on the hollow cylinder at P. vP′=−4ω0Ri^. Since ωh=ω0 is constant, αh=0. aP′=αh×rOP+ωh×(ωh×rOP). aP′=0+(−ω0k^)×((−ω0k^)×(−4Rj^))=(−ω0k^)×(−4ω0R(k^×j^))=(−ω0k^)×(4ω0Ri^)=−4ω02R(k^×i^)=−4ω02Rj^.
Substituting into the differentiated no-slip condition: 12ω02Rj^+αs×(−Rj^)+(2ω0k^)×(2ω0Ri^)=−4ω02Rj^. 12ω02Rj^+αs×(−Rj^)+4ω02R(k^×i^)=−4ω02Rj^. 12ω02Rj^+αs×(−Rj^)+4ω02Rj^=−4ω02Rj^. 16ω02Rj^+αs×(−Rj^)=−4ω02Rj^. αs×(−Rj^)=−20ω02Rj^. Let αs=αsk^. Then (αsk^)×(−Rj^)=−Rαs(k^×j^)=Rαsi^. Rαsi^=−20ω02Rj^. This equation implies αs=0 and 0=−20ω02Rj^, which is a contradiction unless ω0=0. There must be a mistake in setting up the equations or assumptions.
Let's recheck the calculation of aC. C is moving in a circle of radius 3R about O with angular velocity 2ω0. At the instant shown, C is at (0,−3R), so rC=−3Rj^. The velocity is vC=−6ω0Ri^. The acceleration is purely centripetal towards O, since the speed is constant if ωOC is constant. aC=−ωOC2rC=−(2ω0)2(−3Rj^)=4ω02(3Rj^)=12ω02Rj^. This matches the previous calculation.
Let's recheck the calculation of aP′. P' is moving in a circle of radius 4R about O with angular velocity ω0. At the instant shown, P' is at (0,−4R), so rOP′=−4Rj^. The velocity is vP′=−4ω0Ri^. The acceleration is purely centripetal towards O. aP′=−ωh2rOP′=−(ω0)2(−4Rj^)=4ω02Rj^. The calculation of aP′ was incorrect.
Substituting into the differentiated no-slip condition: aC+αs×rCP+ωs×vP/C=aP′. 12ω02Rj^+αs×(−Rj^)+(2ω0k^)×(2ω0Ri^)=4ω02Rj^. 12ω02Rj^+αs×(−Rj^)+4ω02Rj^=4ω02Rj^. 16ω02Rj^+αs×(−Rj^)=4ω02Rj^. αs×(−Rj^)=−12ω02Rj^. Let αs=αsk^. Then Rαsi^=−12ω02Rj^. This still leads to a contradiction.
Let's consider the acceleration of P on the solid cylinder relative to C: aP/C=αs×rCP+ωs×(ωs×rCP). ωs×rCP=2ω0Ri^. ωs×(ωs×rCP)=(2ω0k^)×(2ω0Ri^)=4ω02Rj^. So, aP=aC+αs×rCP+ωs×(ωs×rCP). aP=12ω02Rj^+αs×(−Rj^)+4ω02Rj^=16ω02Rj^+αs×(−Rj^). No slip condition aP=aP′. 16ω02Rj^+αs×(−Rj^)=4ω02Rj^. αs×(−Rj^)=−12ω02Rj^. Let αs=αsk^. Then Rαsi^=−12ω02Rj^. Still a contradiction.
Let's assume the figure is in the vertical plane, and the rotation is about a horizontal axis perpendicular to the plane. Let the x-axis be horizontal to the right, and the y-axis be vertically upwards. Let O be the origin. At the given instant, C is at (0,−3R). The hollow cylinder rotates clockwise with ω0 about O. The line OC rotates clockwise with 2ω0 about O. ωh=−ω0k^. ωOC=−2ω0k^. rC=−3Rj^. vC=ωOC×rC=(−2ω0k^)×(−3Rj^)=−6ω0Ri^. aC=ωOC×vC=(−2ω0k^)×(−6ω0Ri^)=12ω02Rj^. Point P on hollow cylinder: rOP=−4Rj^. vP′=ωh×rOP=(−ω0k^)×(−4Rj^)=−4ω0Ri^. aP′=ωh×vP′=(−ω0k^)×(−4ω0Ri^)=4ω02Rj^. Let ωs be the angular velocity of the solid cylinder about C. Let ωs=ωsk^. Velocity of P on solid cylinder: vP=vC+ωs×rCP=−6ω0Ri^+(ωsk^)×(−Rj^)=−6ω0Ri^+Rωsi^. No slip: vP=vP′. −6ω0Ri^+Rωsi^=−4ω0Ri^. Rωs=2ω0R, so ωs=2ω0. ωs=2ω0k^.
Let αs=αsk^ be the angular acceleration of the solid cylinder about C. Acceleration of P on solid cylinder: aP=aC+αs×rCP+ωs×(ωs×rCP). aP=12ω02Rj^+(αsk^)×(−Rj^)+(2ω0k^)×((2ω0k^)×(−Rj^)). (αsk^)×(−Rj^)=Rαsi^. (2ω0k^)×((2ω0k^)×(−Rj^))=(2ω0k^)×(2ω0Ri^)=4ω02Rj^. aP=12ω02Rj^+Rαsi^+4ω02Rj^=Rαsi^+16ω02Rj^. No slip: aP=aP′. Rαsi^+16ω02Rj^=4ω02Rj^. Rαsi^=−12ω02Rj^. This still gives a contradiction.
Let's check if the direction of ωs is correct. If the hollow cylinder moves left at the bottom, the solid cylinder should rotate clockwise relative to its center to roll left. So ωs=−ωsk^. Then vP=−6ω0Ri^+(−ωsk^)×(−Rj^)=−6ω0Ri^−Rωsi^. No slip: −6ω0Ri^−Rωsi^=−4ω0Ri^. −Rωs=2ω0R, so ωs=−2ω0. This means ωs is 2ω0 in the direction of −k^. So ωs=−2ω0k^.
Let's recalculate acceleration with ωs=−2ω0k^. ωs×rCP=(−2ω0k^)×(−Rj^)=−2ω0Ri^. ωs×(ωs×rCP)=(−2ω0k^)×(−2ω0Ri^)=4ω02Rj^. aP=aC+αs×rCP+ωs×(ωs×rCP). aP=12ω02Rj^+(αsk^)×(−Rj^)+4ω02Rj^=Rαsi^+16ω02Rj^. No slip: Rαsi^+16ω02Rj^=4ω02Rj^. Rαsi^=−12ω02Rj^. Still a contradiction.
Let's check option (B). Magnitude of acceleration of point A of solid cylinder is 88ω02R. Point A is the topmost point of the solid cylinder. rCA=Rj^. vA=vC+ωs×rCA=−6ω0Ri^+(−2ω0k^)×(Rj^)=−6ω0Ri^−2ω0R(k^×j^)=−6ω0Ri^−2ω0R(−i^)=−4ω0Ri^.
aA=aC+αs×rCA+ωs×(ωs×rCA). Assuming αs=0. ωs×rCA=(−2ω0k^)×(Rj^)=−2ω0Ri^. ωs×(ωs×rCA)=(−2ω0k^)×(−2ω0Ri^)=4ω02Rj^. aA=12ω02Rj^+0+4ω02Rj^=16ω02Rj^. Magnitude is 16ω02R. This does not match 88ω02R.
Let's recheck the calculation of ωs. Velocity of P on solid cylinder relative to C: vP/C=ωs×rCP. Velocity of P on hollow cylinder relative to C: vP′/C=vP′−vC=−4ω0Ri^−(−6ω0Ri^)=2ω0Ri^. No slip: vP/C=vP′/C. ωs×(−Rj^)=2ω0Ri^. Let ωs=ωsk^. Then Rωsi^=2ω0Ri^, so ωs=2ω0. So angular velocity of solid cylinder about its own axis is 2ω0. Option (A) is incorrect.
Let's assume there is a mistake in the problem statement or options. Let's review the options and see if any can be derived under some plausible assumptions.
Let's assume the angular acceleration of the solid cylinder is zero, αs=0. Then aA=16ω02Rj^. ∣aA∣=16ω02R.
Given that a solution B is provided, and our calculations consistently lead to contradictions or different values, it is highly likely there is an error in the problem statement or the options. However, if forced to choose from the options based on some hidden assumption or interpretation, it's difficult without further information or clarification.
Since I cannot rigorously derive the solution from the given information, I cannot provide a correct and detailed explanation. However, if we assume that the problem is well-posed and option B is correct, then the magnitude of acceleration of point A is 88ω02R.