Cylinder Rotational Motion Question

In summary, the problem involves a sphere of radius a rolling without slipping on top of a fixed rough circular cylinder of radius R. The angle θ to the vertical made by the line joining the centre of the sphere directly to the axis of the cylinder is related to the angular velocity squared (w)^2 by the formula (w)^2 = [10g(1 - cos θ)] / [7(R+a)], where g is the acceleration due to gravity. By using the equation for kinetic and potential energy and considering when the normal force becomes zero, it can be shown that the sphere will leave the surface of the cylinder when θ = arccos (10/17).
  • #1
kongieieie
6
0
A sphere of radius a rests on top of a fixed rough circular cylinder of radius R which is lying with its principal axis horizontal. The sphere is disturbed and rolls, without any slipping, around the surface of the cylinder. Show from energy considerations that, if theta is the angle to the vertical made by the line joining the centre of the sphere directly to the axis of the cylinder, then

(w)^2 = [10g(1 - cos theta)] / [7(R+a)]

where (w)^2=angular velocity squared, g=acceleration due to gravity

Hence, show that the sphere will leave the surfacve of the cylinder at

theta = arccos (10/17)
 
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  • #2
Welcome to PF!

Hi kongieieie! Welcome to PF! :smile:

(have a theta: θ and an omega: ω and try using the X2 tag just above the Reply box :wink:)
kongieieie said:
Show from energy considerations …

Hence, show that the sphere will leave the surfacve of the cylinder …

Use KE + PE = constant, and v = rω, and remember the sphere will lose contact when the normal force is zero. :wink:

Show us how far you get, and where you're stuck, and then we'll know how to help! :smile:
 
  • #3
Problem solved. Thanks for the hint. :)
 

1. What is cylinder rotational motion?

Cylinder rotational motion refers to the movement of a cylinder around its axis, where one end of the cylinder remains fixed while the other end rotates.

2. What causes cylinder rotational motion?

Cylinder rotational motion is caused by a force applied to the cylinder at a distance from its axis of rotation. This creates a torque, causing the cylinder to rotate.

3. How is the rotational speed of a cylinder calculated?

The rotational speed of a cylinder is calculated by dividing the angular displacement by the time taken for the displacement to occur. It can also be calculated by dividing the linear speed of a point on the cylinder's surface by the cylinder's radius.

4. What is the difference between uniform and non-uniform cylinder rotational motion?

In uniform cylinder rotational motion, the angular speed remains constant, while in non-uniform motion, the angular speed changes over time. This can be caused by varying torque or a change in the distribution of mass on the cylinder.

5. How does friction affect cylinder rotational motion?

Friction can cause a decrease in the rotational speed of a cylinder by creating a torque in the opposite direction of the motion. It can also cause the cylinder to come to a complete stop if the frictional force is greater than the applied force.

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