# Friction and Pulleys

I think the top part of the string should be

haruspex
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I think the top part of the string should beView attachment 81886
That cannot be string, or the pulley would fall down. Must be a rod.
The upper part of the string runs drom the wall to the pulley. How much longer does that get when the car advances 1m?

How much longer does that get when the car advances 1m?
Same as distance covered by small block.

haruspex
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Same as distance covered by small block.
No. Forget the block for the moment, and concentrate on the car, the pulley, the wall, and the length of string from wall to pulley. If the car moves 1m further from the pulley, how much longer is that part of the string?

How much longer does that get when the car advances 1m?
Total length of string - length of the top part of the string ?

haruspex
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Total length of string - length of the top part of the string ?
No, I'm asking about that top part of the string, the part that runs horizontally from the wall to the pulley.

Total length of string -(minus) length of the top part of the string .Right?/QUOTE]

Thank you for your patience .

haruspex
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If the car moves 1m further from the wall, how much further is the pulley from the wall? So how much longer is the piece of string from the wall to the pulley?

1 meter?

haruspex
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1 meter?
Right. So what would be the change in length of the lower part of the string, the part that runs from the block to the pulley?

So what would be the change in length of the lower part of the string
1 meter .

haruspex
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1 meter .
Longer or shorter?

Longer or shorter?
Shorter?

haruspex
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Shorter?
Right. So how much closer is the block to the pulley?

So how much closer is the block to the pulley?
1 meter.so distance covered by block is 1 meter,right?

haruspex
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1 meter.so distance covered by block is 1 meter,right?
It is one metre closer to the pulley. But the pulley has moved how far?

But the pulley has moved how far?
1 meter?

haruspex
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1 meter?
Right. So the pulley is one metre further from the wall, and the block is one metre closer to the pulley. So how far has the block moved away from the wall?

gracy
So how far has the block moved away from the wall?
1 meter.

Right. So how much closer is the block to the pulley?
It is one metre closer to the pulley. But the pulley has moved how far?
Right. So the pulley is one metre further from the wall, and the block is one metre closer to the pulley. So how far has the block moved away from the wall?
By all these questions do you want to say that distance covered by car=distance covered by block

BvU
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No: if the block would NOT be connected to the wall by this wire (and it would NOT move wrt the flat car), THEN the distance covered by the block would be equal to the distance covered by the flat car. So

So the pulley is one metre further from the wall, and the block is one metre closer to the pulley. So how far has the block moved away from the wall?
try again. You have one more attempt left

gracy
Is my post #70 correct?

BvU