Table cloth pulled from underneath a block?

In summary, a block with mass "m" is at rest on a tablecloth that is 80 cm from one end of the table. When the other end of the tablecloth is pulled horizontally with a speed of 1.5 m/s, the block starts to slip and continues to do so until the end of the cloth passes under it. The block then slides on the table until it comes to rest. The coefficient of friction between the block and the table and between the block and the cloth is 0.1. The problem asks for the velocity of the block when it first touches the table and the distance it travels from its initial position before coming to rest. This can be solved by using Newton's second law and considering the
  • #1
draymire
1
0

Homework Statement


A very small block (mass "m") is at rest on a tablecloth on a flat table. the block is 80 cm from end A of the tablecloth. Suddenly, end B of the table cloth is pulled horizontally with speed Vo = 1.5 m/s. the block immediately slips on the cloth and continues to do so until the end of the cloth passes under it. Then the block slides on the table until it comes to rest. (mu) = 0.1 between the block and the table and between the block and the cloth.

a) What is the velocity of the block when it first makes contact with the table?

b) How far from its initial position does the block finally come to rest?


Homework Equations




Vertically

Fnet=ma=N-G

Horizontally

Fnet=P-Ff

Ff=(mu)N

N=mg

The Attempt at a Solution



time before cloth is out from under is 0.8/1.5 seconds


I have no clue where to go on this. if anyone could give me pointers on where to go with this question would be extremely appreciated. I don't want the work done for me just an explanation on how to go about this question.

Thanks!
 
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  • #2
Start by drawing a Free Body Diagram of the small block to determine the net horizontal force acting on it while the tablecloth is being pulled. Then think Newton 2 to determine its acceleration, and it's speed and distance moved based on your time calculation for the length of time it is in touch with the tablecloth. Then repeat this calculation in similar manner to determine the answer to part b.
 
  • #3
draymire said:

Homework Statement


A very small block (mass "m") is at rest on a tablecloth on a flat table. the block is 80 cm from end A of the tablecloth. Suddenly, end B of the table cloth is pulled horizontally with speed Vo = 1.5 m/s. the block immediately slips on the cloth and continues to do so until the end of the cloth passes under it. Then the block slides on the table until it comes to rest. (mu) = 0.1 between the block and the table and between the block and the cloth.

a) What is the velocity of the block when it first makes contact with the table?

b) How far from its initial position does the block finally come to rest?


Homework Equations




Vertically

Fnet=ma=N-G

Horizontally

Fnet=P-Ff

Ff=(mu)N

N=mg

The Attempt at a Solution



time before cloth is out from under is 0.8/1.5 seconds


I have no clue where to go on this. if anyone could give me pointers on where to go with this question would be extremely appreciated. I don't want the work done for me just an explanation on how to go about this question.

Thanks!

Wow, estimating using physics...that's great!

I also measure the size of my Burgundy Tablecloths. Hahaha...can't hardly made it.
 

FAQ: Table cloth pulled from underneath a block?

What is the science behind pulling a table cloth from underneath a block?

The science behind pulling a table cloth from underneath a block is based on inertia and friction. Inertia is the tendency of an object to resist changes in its state of motion, and friction is the force that resists the motion of two surfaces sliding against each other.

How does the table cloth stay in place while the block falls?

The table cloth stays in place due to the property of inertia. As the block is pulled, it creates a force that tries to keep it in its position. This force is strong enough to overcome the force of friction between the table cloth and the table, causing the block to fall while the table cloth stays in place.

What factors affect the success of pulling a table cloth from underneath a block?

The success of pulling a table cloth from underneath a block depends on several factors, such as the type and weight of the block, the type of table cloth, the material and texture of the table, and the speed and angle at which the table cloth is pulled. A smooth and lightweight block, a slick table cloth, and a smooth table surface tend to increase the chances of success.

Is there a specific technique to successfully pull a table cloth from underneath a block?

Yes, there are a few techniques that can increase the chances of success. These include pulling the table cloth quickly and smoothly in a horizontal motion, making sure the table cloth is evenly spread out and free of wrinkles, and pulling at a slight angle to reduce the friction between the cloth and the table.

Can pulling a table cloth from underneath a block be dangerous?

Yes, pulling a table cloth from underneath a block can be dangerous if not done properly. If the table cloth is pulled too slowly or at a wrong angle, the block can fall towards the person pulling it, potentially causing injury. It is important to take proper precautions and practice the technique before attempting it with a heavy or delicate object.

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