What Is the Final Angular Speed of a Spinning Disk with a Running Person?

AI Thread Summary
To determine the final angular speed of a spinning disk with a running person, the conservation of angular momentum principle is applied. The moment of inertia for both the person and the disk is calculated using the formula I = mr². The initial angular momentum is zero since the disk is stationary, leading to the equation 0 = I(person)ω(final person) + I(disk)ω(final disk). The person’s tangential speed and distance from the axis are used to find their contribution to the system's angular momentum. Rearranging the equations correctly allows for the calculation of the disk's final angular speed in rad/s.
teddygrams
Messages
3
Reaction score
0
A flat uniform circular disk (radius = 4.69 m, mass = 280 kg) is initially stationary. The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the center of the disk. A 55.0-kg person, standing 1.59 m from the axis, begins to run on the disk in a circular path and has a tangential speed of 1.70 m/s relative to the ground. Find the resulting angular speed (in rad/s) of the disk.

i know that i have to use :

0=I(person)w(final person) + I(disk)w(final disk)

and i know I=mr^2

but i just don't know how to rearrange everything...correctly..
 
Physics news on Phys.org
post this in the homework section
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Calculating Final Angular Speed of a Rotating Disk with a Horizontal Axis
Replies
8
Views
3K
Angular speed calculation after an inelastic collision
Replies
20
Views
3K
Conservation of Energy and Angular Momentum in a Rotating Train-Disk System
Replies
30
Views
3K
Masses Moving Radially on a Rotating Disk
Replies
8
Views
2K
Minimum initial speed to spin a particle around a disk (with gravity)
Replies
9
Views
2K
What is the final angular displacement of a disk hit by two masses?
Replies
3
Views
2K
Time required for disk to reach angular speed?
Replies
11
Views
2K
Calculating Angular Velocity of Disk w/ Angular Momentum
Replies
1
Views
1K
Determining the Speed of a Rotating Disk with a Constant Force
Replies
10
Views
3K
Angular Velocity & Acceleration for a Series of Connected Objects
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top