What's causes the 'backspin' while sliding a pencil along a table? [duplicate]Why does a ping pong ball change direction when I spin it on a table?Why do wheels appear to revolve opposite to the direction they are rotating?With Newton's third law, why are things capable of moving?Newton's Third Law of MotionWould a phone move upon vibration in a completely uniform situation?Can I make a rod in the vertical plane move with its one end on the ground in a slanting position?Different directions of frictional force when objects are rollingWeird phenomenon on aluminum laptop casingWhat causes the variable brightness intensity along the filament of an incandescent bulb?Can a gust of wind have a distinct blade-like edge?Rolling Without Slipping and Rotational Energy
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What's causes the 'backspin' while sliding a pencil along a table? [duplicate]
Why does a ping pong ball change direction when I spin it on a table?Why do wheels appear to revolve opposite to the direction they are rotating?With Newton's third law, why are things capable of moving?Newton's Third Law of MotionWould a phone move upon vibration in a completely uniform situation?Can I make a rod in the vertical plane move with its one end on the ground in a slanting position?Different directions of frictional force when objects are rollingWeird phenomenon on aluminum laptop casingWhat causes the variable brightness intensity along the filament of an incandescent bulb?Can a gust of wind have a distinct blade-like edge?Rolling Without Slipping and Rotational Energy
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This question already has an answer here:
Why does a ping pong ball change direction when I spin it on a table?
4 answers
I've always thought it was weird that pencils act like this: if one pulls their finger along the side of a pencil until it touches the surface below, the pencil is launched in the opposite direction of the way that the finger moved. Why is this?
newtonian-mechanics forces rotational-dynamics everyday-life
New contributor
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marked as duplicate by Qmechanic♦ Apr 27 at 19:04
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
$begingroup$
This question already has an answer here:
Why does a ping pong ball change direction when I spin it on a table?
4 answers
I've always thought it was weird that pencils act like this: if one pulls their finger along the side of a pencil until it touches the surface below, the pencil is launched in the opposite direction of the way that the finger moved. Why is this?
newtonian-mechanics forces rotational-dynamics everyday-life
New contributor
$endgroup$
marked as duplicate by Qmechanic♦ Apr 27 at 19:04
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
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Possible duplicates: physics.stackexchange.com/q/16271/2451 and links therein.
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– Qmechanic♦
Apr 27 at 19:04
add a comment |
$begingroup$
This question already has an answer here:
Why does a ping pong ball change direction when I spin it on a table?
4 answers
I've always thought it was weird that pencils act like this: if one pulls their finger along the side of a pencil until it touches the surface below, the pencil is launched in the opposite direction of the way that the finger moved. Why is this?
newtonian-mechanics forces rotational-dynamics everyday-life
New contributor
$endgroup$
This question already has an answer here:
Why does a ping pong ball change direction when I spin it on a table?
4 answers
I've always thought it was weird that pencils act like this: if one pulls their finger along the side of a pencil until it touches the surface below, the pencil is launched in the opposite direction of the way that the finger moved. Why is this?
This question already has an answer here:
Why does a ping pong ball change direction when I spin it on a table?
4 answers
newtonian-mechanics forces rotational-dynamics everyday-life
newtonian-mechanics forces rotational-dynamics everyday-life
New contributor
New contributor
edited Apr 27 at 18:14
Rishi
3,74972442
3,74972442
New contributor
asked Apr 27 at 14:10
StormblessedStormblessed
1294
1294
New contributor
New contributor
marked as duplicate by Qmechanic♦ Apr 27 at 19:04
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
marked as duplicate by Qmechanic♦ Apr 27 at 19:04
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
$begingroup$
Possible duplicates: physics.stackexchange.com/q/16271/2451 and links therein.
$endgroup$
– Qmechanic♦
Apr 27 at 19:04
add a comment |
$begingroup$
Possible duplicates: physics.stackexchange.com/q/16271/2451 and links therein.
$endgroup$
– Qmechanic♦
Apr 27 at 19:04
$begingroup$
Possible duplicates: physics.stackexchange.com/q/16271/2451 and links therein.
$endgroup$
– Qmechanic♦
Apr 27 at 19:04
$begingroup$
Possible duplicates: physics.stackexchange.com/q/16271/2451 and links therein.
$endgroup$
– Qmechanic♦
Apr 27 at 19:04
add a comment |
2 Answers
2
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The sequence of events is shown below.
Initially the pencil is propelled forward with speed $v_rm A$ but has backspin $omega_rm A$ (anticlockwise rotation) so there is relative movement between the pencil and the surface as $v_rm A ne romega_rm A$ where $r$ is the radius of the pencil.
A kinetic friction force acts which reduces the rotational speed of the pencil $omega_rm B$ until there is no rotation of the pencil $omega_rm C=0$ but the pencil is still moving forward $v_rm C$.
The frictional force then starts the pencil rotating clockwise with increasing angular speed and eventually the no slip condition, $v_rm D = romega_rm D$, is reached.
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add a comment |
$begingroup$
As the finger comes down the side of the pencil, two things happen:
A compression that imparts a horizontal force taking the pencil away from the finger
And a rotation that causes the pencil to rotate tending to bring the pencil back to the start point
These combine to define how far the pencil travels before it stops.
The use of spin can be seen on a snooker or billiards table : top, bottom and side...
New contributor
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add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
The sequence of events is shown below.
Initially the pencil is propelled forward with speed $v_rm A$ but has backspin $omega_rm A$ (anticlockwise rotation) so there is relative movement between the pencil and the surface as $v_rm A ne romega_rm A$ where $r$ is the radius of the pencil.
A kinetic friction force acts which reduces the rotational speed of the pencil $omega_rm B$ until there is no rotation of the pencil $omega_rm C=0$ but the pencil is still moving forward $v_rm C$.
The frictional force then starts the pencil rotating clockwise with increasing angular speed and eventually the no slip condition, $v_rm D = romega_rm D$, is reached.
$endgroup$
add a comment |
$begingroup$
The sequence of events is shown below.
Initially the pencil is propelled forward with speed $v_rm A$ but has backspin $omega_rm A$ (anticlockwise rotation) so there is relative movement between the pencil and the surface as $v_rm A ne romega_rm A$ where $r$ is the radius of the pencil.
A kinetic friction force acts which reduces the rotational speed of the pencil $omega_rm B$ until there is no rotation of the pencil $omega_rm C=0$ but the pencil is still moving forward $v_rm C$.
The frictional force then starts the pencil rotating clockwise with increasing angular speed and eventually the no slip condition, $v_rm D = romega_rm D$, is reached.
$endgroup$
add a comment |
$begingroup$
The sequence of events is shown below.
Initially the pencil is propelled forward with speed $v_rm A$ but has backspin $omega_rm A$ (anticlockwise rotation) so there is relative movement between the pencil and the surface as $v_rm A ne romega_rm A$ where $r$ is the radius of the pencil.
A kinetic friction force acts which reduces the rotational speed of the pencil $omega_rm B$ until there is no rotation of the pencil $omega_rm C=0$ but the pencil is still moving forward $v_rm C$.
The frictional force then starts the pencil rotating clockwise with increasing angular speed and eventually the no slip condition, $v_rm D = romega_rm D$, is reached.
$endgroup$
The sequence of events is shown below.
Initially the pencil is propelled forward with speed $v_rm A$ but has backspin $omega_rm A$ (anticlockwise rotation) so there is relative movement between the pencil and the surface as $v_rm A ne romega_rm A$ where $r$ is the radius of the pencil.
A kinetic friction force acts which reduces the rotational speed of the pencil $omega_rm B$ until there is no rotation of the pencil $omega_rm C=0$ but the pencil is still moving forward $v_rm C$.
The frictional force then starts the pencil rotating clockwise with increasing angular speed and eventually the no slip condition, $v_rm D = romega_rm D$, is reached.
answered Apr 27 at 17:08
FarcherFarcher
52.6k340112
52.6k340112
add a comment |
add a comment |
$begingroup$
As the finger comes down the side of the pencil, two things happen:
A compression that imparts a horizontal force taking the pencil away from the finger
And a rotation that causes the pencil to rotate tending to bring the pencil back to the start point
These combine to define how far the pencil travels before it stops.
The use of spin can be seen on a snooker or billiards table : top, bottom and side...
New contributor
$endgroup$
add a comment |
$begingroup$
As the finger comes down the side of the pencil, two things happen:
A compression that imparts a horizontal force taking the pencil away from the finger
And a rotation that causes the pencil to rotate tending to bring the pencil back to the start point
These combine to define how far the pencil travels before it stops.
The use of spin can be seen on a snooker or billiards table : top, bottom and side...
New contributor
$endgroup$
add a comment |
$begingroup$
As the finger comes down the side of the pencil, two things happen:
A compression that imparts a horizontal force taking the pencil away from the finger
And a rotation that causes the pencil to rotate tending to bring the pencil back to the start point
These combine to define how far the pencil travels before it stops.
The use of spin can be seen on a snooker or billiards table : top, bottom and side...
New contributor
$endgroup$
As the finger comes down the side of the pencil, two things happen:
A compression that imparts a horizontal force taking the pencil away from the finger
And a rotation that causes the pencil to rotate tending to bring the pencil back to the start point
These combine to define how far the pencil travels before it stops.
The use of spin can be seen on a snooker or billiards table : top, bottom and side...
New contributor
New contributor
answered Apr 27 at 14:18
Solar MikeSolar Mike
1274
1274
New contributor
New contributor
add a comment |
add a comment |
0 N,YvrA,IHiGZk2kR,dGBHouwPxLkBpgcr w8W3b,F,UT5,NiEl
$begingroup$
Possible duplicates: physics.stackexchange.com/q/16271/2451 and links therein.
$endgroup$
– Qmechanic♦
Apr 27 at 19:04