One hollow and one solid cylinder of the same radius are rolling down an inclined plane. Which of them will reach the end of the plane first?
Correct answer: A. Solid cylinder
- A. Solid cylinder
- B. Hollow cylinder
- C. Both simultaneously
- D. Depends upon the behavior among them
Explanation
mgcos∅ will get balanced by the normal force For rolling without slipping (pure rolling), we have a = àR ... (1) I am using symbol à for angular acceleration Two forces are acting, f and mgsin∅ submission of F =ma mg sin∅ -f= ma ... (2) (Here f is the friction force, a = linear acceleration à = angular acceleration) As we know, T= là (T=torque, I=inertia) from eqn(1)....à=a/R T=I(a/R) We know torque equals force into the radius But we also know the force of friction and radius are also perpendicular so T = f×R f×R = I ( a/R ) f =I ( a/R² ).......(3) From eqn (2) and (3), mgsin∅ - I ( a/R² ) =ma a = (mgsin∅) / (1/R²+m) a = (mgR²sin∅) / I+mR² m, R and ∅ are constant So, a is proportional to 1/I (I=inertia) The body whose inertia will less reach the bottom first We know, Inertia of solid cylinder = ½ mR² Inertia of hollow cylinder= ½ m ( R2² +R1²) I (solid) < I (hollow) So solid cylinder will have greater acceleration So, it will reach the end first
This question appeared on the ETEA MDCAT 2005 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Angular and Linear Quantities
Rotational motion relates angular displacement, angular velocity and angular acceleration to linear displacement, tangential velocity and tangential acceleration through the radius. Questions use radians, v equals r omega and tangential acceleration, while distinguishing tangential velocity from centripetal acceleration and angular quantities from their linear counterparts.
Practise Rotational and Circular Motion
521 free Rotational and Circular Motion MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Angular and Linear Quantities questions
A particle of mass 'm' is moving on a circular path of radius 'r' with velocity 'v', then centripetal force acting on it is F. if the velocity of particle increases by 2 times and radius of circular path increases by 4 times then new centripetal force F' will be;
The centripetal acceleration of an object moving along a circle of radius 'r' with an angular speed 'w' is given by the formula:
A fighter plane is moving in a vertical circle of radius r. Its minimum velocity at the highest point of the circle will be?
Diver curls his bosy when diving so that he can perform some quick somersaults. This is because:
A particle is moving in a circle of radius r with a constant angular speed . Its acceleration directed towards the center of the circle is:
The vectoral form of centripetal force is: