Need help in determining normal force the question is from ss krotov

Click For Summary
SUMMARY

The discussion focuses on calculating the normal force (N) exerted by a cylinder of mass m and radius r on a stationary support while it rolls between two supports, one fixed and the other sliding with velocity v. The problem involves neglecting friction and analyzing the forces acting on the cylinder, leading to the equation mgcos45 - N = mv²/r. The user struggles to derive the correct expression for N and seeks clarification on the horizontal component of the cylinder's velocity, which the provided solution states is v/2.

PREREQUISITES
  • Understanding of classical mechanics, specifically dynamics of rolling motion
  • Knowledge of moment of inertia, particularly for a solid cylinder
  • Familiarity with energy conservation principles in physics
  • Basic trigonometry, especially properties of right triangles
NEXT STEPS
  • Study the derivation of normal force in rolling motion scenarios
  • Learn about the relationship between linear and angular velocity in rolling objects
  • Explore the concept of work-energy principle in mechanics
  • Investigate the effects of friction in rolling motion and its absence
USEFUL FOR

Students of physics, particularly those studying mechanics, engineers working on dynamic systems, and educators seeking to clarify concepts related to rolling motion and forces.

ishanp
Messages
2
Reaction score
0
cylinder of mass m and radius r rests on two supports of same height. one is fixed other slides with velocity v.determine normal force N by the cylinder on stationary support at the moment when distance between the point of contacts A and B of cylinder and support) is r√2assuming supports were very close to each other at the initial moment. friction between cylinder and support should be neglected.


my attempt;

r^2 +r^2=(r√2)^2

since friction is neglected the forces exerted on cylinder by supports are always normal to its surface they do zero work. only graviy does work on it. since the triangle formed by radii and AB is rt angled other angles are of 45 degree. work done till that moment=mg(r-r√2/2) . i think that the cylinder rolls without slipping about point of contact with stationary axis(A). moment of inertia about it is 3/2mr^2.if i take v=rω and put work equal to KE will get v of centre of mass and then since com moves in circle centered at A
mgcos45-N=mv^2/r ans is not coming
it is my first post here . thanks
 
Physics news on Phys.org
ishanp said:
cylinder of mass m and radius r rests on two supports of same height. one is fixed other slides with velocity v.determine normal force N by the cylinder on stationary support at the moment when distance between the point of contacts A and B of cylinder and support) is r√2assuming supports were very close to each other at the initial moment. friction between cylinder and support should be neglected.


my attempt;

r^2 +r^2=(r√2)^2

since friction is neglected the forces exerted on cylinder by supports are always normal to its surface they do zero work. only graviy does work on it. since the triangle formed by radii and AB is rt angled other angles are of 45 degree. work done till that moment=mg(r-r√2/2) . i think that the cylinder rolls without slipping about point of contact with stationary axis(A). moment of inertia about it is 3/2mr^2.if i take v=rω and put work equal to KE will get v of centre of mass and then since com moves in circle centered at A
mgcos45-N=mv^2/r ans is not coming
it is my first post here . thanks

problem is 1.45
solution at back says horizontal component of cylinder's velocity is v/2 .
i don't know how
 

Similar threads

Replies
13
Views
2K
  • · Replies 5 ·
Replies
5
Views
4K
Replies
13
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 12 ·
Replies
12
Views
4K
  • · Replies 47 ·
2
Replies
47
Views
9K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 7 ·
Replies
7
Views
6K
  • · Replies 2 ·
Replies
2
Views
3K