Rotational Dynamics - sphere,block,pulley

Click For Summary
SUMMARY

The discussion focuses on calculating the dynamics of a system involving a solid sphere and a block connected by a rope over a pulley. The solid sphere has a moment of inertia of I=(2/5)MR^2, a radius of R=0.10m, and a mass of 2kg, while the block has a mass of 1kg. Key calculations include determining the acceleration of the system, the tension in the rope, and the speed of the block after descending 0.25m using energy methods. The presence of friction is acknowledged, which influences both the linear and angular acceleration of the sphere.

PREREQUISITES
  • Understanding of Newton's 2nd Law of Motion
  • Knowledge of rotational dynamics and moment of inertia
  • Familiarity with the relationship between linear and angular motion
  • Basic principles of energy conservation in mechanical systems
NEXT STEPS
  • Study the derivation of Newton's 2nd Law in rotational systems
  • Learn about the relationship between linear acceleration (a) and angular acceleration (α)
  • Explore the concept of friction in rolling motion and its effects on acceleration
  • Investigate energy conservation methods in mechanical systems, particularly in pulley setups
USEFUL FOR

Physics students, mechanical engineers, and anyone interested in understanding rotational dynamics and the mechanics of pulley systems.

nyyfan0729
Messages
12
Reaction score
0
:confused: A solid sphere (I=(2/5)MR^2) with a radius R=0.10m is attatched to a massless rope by a frictionless axle that passes through the center of the sphere. The rope passes over an ideal pulley and is connected to a 1kg block. The sphere has a mass of 2kg. The surface has a meu that cannot equal 0. Assume that the ball always rolls without slipping and that the system is released from rest.
Calculate:
a. the acceleration of the system
b. the tension in the rope
c. the speed of the 1kg mass, by energy methods, after it has descended 0.25m.

PLEASE HELP. I HAVE NO IDEA WHAT TO DO!
 
Physics news on Phys.org
Finding the acceleration is a little bit involved.

There is a small amount of (unknown) friction acting on the sphere, call it R.
Now use Newton's 2nd law to get an expression, involving R, for the (linear) acceleration, a, of the sphere/block mass system.

The small amount of friction is what makes the sphere rotate as it moves along the table (?) surface.
Since this friction force rotates the sphere, then what is the angular acceleration of the sphere ?

If any object is rolling along a surface with a linear speed of v m/s, then what is the relationship between that speed and the object's angular velocity, ω ?

Similarly, what is the relationship between an objects linear acceleration, a, and its angular acceleration, α ?

You should now have three eqns invloving three unknown, R, a and α.
 

Similar threads

  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
13
Views
3K
  • · Replies 10 ·
Replies
10
Views
6K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 10 ·
Replies
10
Views
7K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 35 ·
2
Replies
35
Views
5K