Why coin drop down into the glass?

  • Context: High School 
  • Thread starter Thread starter Aladin
  • Start date Start date
  • Tags Tags
    Drop Glass
Click For Summary

Discussion Overview

The discussion centers around the phenomenon of a coin dropping into a glass when a boardcard, on which the coin is placed, is struck. Participants explore the underlying physics concepts, particularly inertia and friction, and how they relate to the motion of the coin.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that the inertia of the coin is a key factor in understanding why it drops into the glass when the boardcard is hit.
  • Others mention that the force of friction between the coin and the board is insufficient to overcome the inertia of the coin, leading to its downward motion.
  • A participant compares the situation to the trick of pulling a tablecloth while leaving dishes behind, illustrating the concept of inertia.
  • There is a discussion about the role of static versus kinetic friction, noting that static friction can move the coin with the card if the card is moved slowly, while kinetic friction is less effective when the card is moved quickly.
  • One participant expresses confusion about the original question, indicating that clarity is needed for a proper answer.

Areas of Agreement / Disagreement

Participants generally agree that inertia plays a significant role in the coin's behavior, but there is some confusion regarding the initial question and the specifics of the physics involved. Multiple perspectives on the role of friction and inertia are presented, indicating that the discussion remains somewhat unresolved.

Contextual Notes

Some assumptions about the level of understanding of the participants are not explicitly stated, and the discussion does not resolve the nuances of how inertia and friction interact in this scenario.

Who May Find This Useful

Individuals interested in basic physics concepts, particularly those related to motion, inertia, and friction, may find this discussion informative.

Aladin
Messages
77
Reaction score
0
When we put a coin on a boardcard and both the boardcard and coin put on a glass.
when we hit the boardcard,why the coin drop down into the glass.??
 

Attachments

  • 1.GIF
    1.GIF
    909 bytes · Views: 1,297
  • 2.GIF
    2.GIF
    1.2 KB · Views: 1,524
Physics news on Phys.org
what?? I don't understand...
 
Are you asking about the inertia of the coin or the surface tension of the water?\
 
inertia...it seems to say nothing bout water at all.
 
Well the short answer is that the force of friction between the coin and the board is not great enough to overcome the inertia of the coin

I suppose he knew that though...?
 
subodei said:
the force of friction between the coin and the board is not great enough to overcome the inertia of the coin

I suppose he knew that though...?
Apparently not, or he wouldn't have asked. We have no idea how old this lad is, or what his level of education is.
The inertial of the coin is very high, and as suodei said, overpowers the forces that hold it to the board. When the board is abruptly removed, the coin stays behind. It's the same principle as the old trick of pulling a tablecloth off while leaving the dishes behind. With a slower movement, the coin would stay with the card.
 
Aladin said:
When we put a coin on a boardcard and both the boardcard and coin put on a glass.
when we hit the boardcard,why the coin drop down into the glass.??
As several have noted, the answer relates to the inertia of the coin. All objects that have mass require a force to get them moving (or change their state of motion). The only horizontal force on the coin is the friction between card and coin. If there were no friction, then you could slide the card away at any speed and the coin wouldn't move (until it started falling, of course).

But there is friction. If you move the card slowly, then static friction will move the coin along with the card. But if you move the card quickly, the much lower kinetic friction will be acting: the coin will move, but not as quickly as the card. Now if you move the card real quick, that friction force won't have much time to accelerate the coin; it appears to fall straight down (actually it must move a little to the side as well).
 
Doc Al said:
As several have noted, the answer relates to the inertia of the coin.

Of course there is no answer if the question is not understood. :frown:
 
Thank you Doc Al my problem is solved by your answer.
 

Similar threads

Undergrad Why Does a Glass Move Outward When Opening the Fridge Door?
  • · Replies 154 ·
6
Replies
154
Views
9K
High School Pressure of air inside a glass
  • · Replies 3 ·
Replies
3
Views
2K
Graduate Bubbles in a falling glass of champagne
  • · Replies 20 ·
Replies
20
Views
5K
High School Can Dropping Glass on the Floor Cause Spalling and Ejection of Particles?
  • · Replies 5 ·
Replies
5
Views
7K
Undergrad Relative speed and coin dropping
  • · Replies 10 ·
Replies
10
Views
2K
High School Conversion of Potential Energy: Sound or Heat?
  • · Replies 12 ·
Replies
12
Views
3K
High School Quiz Question -- What happens to the cork?
  • · Replies 8 ·
Replies
8
Views
2K
High School Unanswered Questions about Tossed Coins
  • · Replies 46 ·
2
Replies
46
Views
12K
High School Coin Experiment: Upright on Rim, Why?
  • · Replies 7 ·
Replies
7
Views
3K
High School Is the Coin Biased Towards Heads? Statistical Test and Conclusion
  • · Replies 21 ·
Replies
21
Views
4K