- #1
minimario
- 95
- 2
Homework Statement
Homework Equations
##v = r \omega ##??
The Attempt at a Solution
The answer is 0...why?
Why is the Instantaneous Speed Zero in this Rotational Motion Problem?
Click For Summary
Homework Help Overview
The discussion revolves around a rotational motion problem where the instantaneous speed of a rolling object is questioned. Participants explore the relationship between translational and rotational speeds in the context of rolling without slipping.
Discussion Character
- Exploratory, Conceptual clarification, Assumption checking
Approaches and Questions Raised
- Participants discuss the implications of rolling without slipping and question the definitions of instantaneous speed. They explore how translational and rotational speeds interact at the point of contact.
Discussion Status
Some participants have provided insights into the mechanics of rolling motion, noting that the translational and rotational speeds at the point of contact are equal and opposite. However, there is recognition of insufficient data to fully resolve the problem.
Contextual Notes
There is an acknowledgment of missing information necessary for calculating the rotational speed of the point of contact, which is central to the discussion.
##v = r \omega ##??
The answer is 0...why?
- #2
HallsofIvy
Science Advisor
Homework Helper
- 42,895
- 983
Because the "object is rolling without slipping". That means that any point on the objects circumfence that is in contact with the surface on which it is rolling does not move forward of backward on the surface.
(Oh, and saying "the instantaneous speed is 0" is NOT the same as saying "there is no instantaneous speed"!)
(Oh, and saying "the instantaneous speed is 0" is NOT the same as saying "there is no instantaneous speed"!)
- #3
spaghetti3451
- 1,311
- 31
The speed of any point of the rolling body is the sum of its speed due to translational motion and its speed due to rotational motion.
What is the translational speed of the point of contact of the rolling body?
What is the rotational speed of the point of contact of the rolling body?
What is the translational speed of the point of contact of the rolling body?
What is the rotational speed of the point of contact of the rolling body?
- #4
spaghetti3451
- 1,311
- 31
Well, I now see that there isn't enough data in the problem to calculate the rotational speed of the point of contact. But, the key idea is that the translational speed and the rotational speed are equal and opposite, leading to a net force of zero.
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