Find the pebble's position, velocity, and acceleration

AI Thread Summary
The discussion focuses on determining the position, velocity, and acceleration of a pebble lodged in a tire rolling without slipping. The velocity is expressed as a combination of the tire's constant speed and angular motion. To find the acceleration, the proposed formula incorporates both radial and tangential components. The position of the pebble over time can be calculated by integrating the velocity function. Cartesian coordinates are recommended for clarity, necessitating transformations based on the tire's movement.
tronter
Messages
183
Reaction score
1
A tire rolls in a straight line without slipping. Its center moves with constant speed V. A small pebble lodged in the read of the tire touches the road at t = 0. Find the pebble's position, velocity, and acceleration as functions of time.

So \bold{v} = \dot{r} \bold{\hat{r}} + r \theta \bold{\hat{\theta}}.

Would it just be \bold{v} = V \bold{\hat{r}} + Vt \omega \bold{\hat{\theta}} and \bold{a} = -Vt \omega^{2} \bold{\hat{r}} + 2V \omega \bold{\hat{\theta}}?

Then to find the position as a function of time, integrate the velocity?

Thanks
 
Last edited:
Physics news on Phys.org
You need to do this in cartesian coords, because the center keeps moving.
 
So use the transformations x = r \cos \theta, y = r \sin \theta?
 
I had to do a problem similar to this, and I still don't understand it...
 
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...
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...
Back
Top