Circular Motion and Forces: Net Force on Sliding Package?

Click For Summary

Homework Help Overview

The discussion revolves around a conceptual question regarding the net force acting on a package sliding in a car that is turning left along a circular path. Participants explore the dynamics of circular motion and the forces involved, particularly focusing on the concepts of centripetal force and inertia.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the nature of forces acting on the package, including the misconception of "centrifugal force" and the role of friction and inertia. Questions are raised about the direction of forces and the balance between friction and inertia during the turn.

Discussion Status

Some participants have provided insights into the forces at play, questioning the existence of centrifugal force and discussing the implications of inertia. There is an ongoing exploration of the correct interpretation of the forces involved, with some participants expressing uncertainty about their understanding.

Contextual Notes

Participants note the potential confusion surrounding the definitions and roles of forces in circular motion, particularly regarding the assumptions about friction and the net force on the package. There is a lack of consensus on the best answer to the original question, indicating a need for further clarification.

Greywolfe1982
Messages
60
Reaction score
0

Homework Statement



A car initially travels north and then turns to the left along a circular curve. This causes a package on the seat of the car to slide toward the right side of the car. Which of the following is true about the net force on the package while it is sliding?

1. The force is directed north.
2. There is not enough force directed toward the center of the circle to keep the package
from sliding.
3. There is not enough force tangential to the car’s path to keep the package from sliding.
4. There is not enough force directed north to keep the package from sliding.
5. The force is directed away from the center of the circle.

Homework Equations



N/A (I think? Conceptual question as far as I know)

The Attempt at a Solution



So from what I understand there is a centrifugal force that is created as the car turns, which wants to push the box outward, along the line perpendicular to the tangent of velocity. So I'll go over what I'm thinking for each answer -

1. Doesn't seem right at all to me. I believe the direction of the force is changing as the car is turning.
2. One of my first thoughts. Either friction or centripetal force (I'm thinking the latter) would be smaller than the centrifugal force causing the box to slide to the right.
3. Don't think this is right, because I'm not even sure of a force tangential to the path, just perpendicular to the tangent.
4. Again, I didn't think there was a force directed to the north...however two answers involving it make me question myself.
5. The second of my two best guesses - wouldn't the centrifugal force be directed away from the center?

I'm sure I'm missing something important - I assume there's a force I'm forgetting...but what is it?
 
Physics news on Phys.org
A. There is no such thing as "centrifugal force"... it does not exist... it is simply inertia's "reaction" to the centripetal force... (this is one of my physics teacher pet peeves...)

B. Now onto the question
1) The car turns so...
2) friction will be directed towards the center ... and what is true about the ability of friction in this case to balance out the packages inertia...
3) If there was a tangential force... which way would it accelerate?
4) see answer 1
5) what force is acting towards the outside of the circle? or is there one?

Hint: I like you order
 
bleedblue1234 said:
A. There is no such thing as "centrifugal force"... it does not exist... it is simply inertia's "reaction" to the centripetal force... (this is one of my physics teacher pet peeves...)

Damn you Yahoo Answers! Not sure why I trusted anything from there, but I was fuzzy on the names and needed a refresher, but apparently I looked in the wrong place.

bleedblue1234 said:
B. Now onto the question
1) The car turns so...
2) friction will be directed towards the center ... and what is true about the ability of friction in this case to balance out the packages inertia...
3) If there was a tangential force... which way would it accelerate?
4) see answer 1
5) what force is acting towards the outside of the circle? or is there one?

Hint: I like you order

1. Wouldn't the centripetal force always be directed towards the center, turning 90 degrees when pointing west to pointing south? Other than friction, that's the only force I know of, apart from the reaction to centripetal force (is that named? Is that even considered a force?)
2. I thought the basis of inertia was that an object in motion wants to stay in motion, an object in rest wants to stay at rest? Unless inertia wanted the box to stay at the start of the turn, wouldn't friction and inertia not balance each other out but be added to each other?
3. If there was a force tangential to the path, I assume it would accelerate along the tangent, which it is doing because of circular motion and the changing direction of velocity.
4. I see it, now just to understand it...
5. Just the reaction to centripetal force, which from what you're saying doesn't sound like a force at all - so I'm assuming it's safe to eliminate this one?

Also, I don't get the hint, I'm rather braindead right now. You think 1. is the best answer?
 
#2 is correct, i think
 
Yup, #2 was it. Thanks for the help.
 

Similar threads

Replies
55
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
Replies
4
Views
1K
Replies
11
Views
1K
Replies
1
Views
940
Replies
9
Views
2K
Replies
6
Views
4K
Replies
19
Views
4K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K