The laws of motion-a block pulled by a light cord

In summary: F-f=ma10cos14.5-0.4x(2.2x9.8-0.1sin14.5)=2.2aOh,i have made a stupid mistake.I can find the correct answer now.In summary, the conversation discussed a problem involving a block of mass 2.20 kg being accelerated across a rough surface by a light cord passing over a small pulley. The tension in the cord was maintained at 10.0N and the pulley was 0.100m above the top of the block. The conversation also mentioned the coefficient of kinetic friction and the
  • #1
haha1234
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Homework Statement


A block of mass 2.20 kg is accelerated across a rough surface by a light cord passing over a small pulley as shown in figure.The tension T in the cord is maintained at 10.0N,and the pulley is 0.100m above the top of the block.The coefficient of kinetic friction is 0.400m.
Determine the acceleration of the block when x=0.400.

Homework Equations





The Attempt at a Solution


Are there any mistake?
tanθ=0.4/0.1
θ=76.0°
F-f=ma
10sinθ-0.4x(2.2x9.8-0.1cosθ)2.2a
 

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  • #2
haha1234 said:
Are there any mistake?
It is a mistake to present a problem like this without an accompanying diagram, and a mistake to attempt to solve it without drawing a forces diagram to help you.

You also haven't indicated the tension in the cord.

http://imageshack.us/scaled/landing/109/holly1756.gif
 
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  • #3
NascentOxygen said:
It is a mistake to present a problem like this without an accompanying diagram, and a mistake to attempt to solve it without drawing a forces diagram to help you.

You also haven't indicated the tension in the cord.

http://imageshack.us/scaled/landing/109/holly1756.gif

Sorry.:shy:
 
Last edited by a moderator:
  • #4
Okay, third mistake, you have attached the wrong pic!
 
  • #5
NascentOxygen said:
Okay, third mistake, you have attached the wrong pic!

Sorry again.
 
  • #6
hi haha1234! :smile:

what is this? :confused: …
haha1234 said:
(2.2x9.8-0.1cosθ)
 
  • #7
tiny-tim said:
hi haha1234! :smile:

what is this? :confused: …

(2.2x9.8-0.1cosθ) is the normal force of the block.
 
  • #8
haha1234 said:
(2.2x9.8-0.1cosθ) is the normal force of the block.

but 0.1cosθ isn't a force, it's a distance :confused:
 
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  • #9
tiny-tim said:
but 0.1cosθ isn't a force, it's a distance :confused:

Oh,i have made a stupid mistake.
I can find the correct answer now.
Thank you!
 
  • #10
deleted
 
Last edited:
  • #11
tanθ=0.1/0.4 <- check it.
 

FAQ: The laws of motion-a block pulled by a light cord

What are the three laws of motion?

The three laws of motion, also known as Newton's laws of motion, are fundamental principles that describe the behavior of objects in motion. The first law states that an object at rest will remain at rest and an object in motion will remain in motion at a constant velocity unless acted upon by an external force. The second law states that the force acting on an object is equal to its mass multiplied by its acceleration. The third law states that for every action, there is an equal and opposite reaction.

How does a block pulled by a light cord demonstrate these laws?

In this scenario, the first law is demonstrated by the block remaining at rest until a force is applied to it by the light cord. The second law is demonstrated by the block's acceleration being directly proportional to the force applied by the cord and inversely proportional to its mass. The third law is demonstrated by the block pulling back on the cord with an equal and opposite force to the force applied by the cord.

What is the role of friction in this scenario?

Friction is the force that opposes motion between two objects in contact. In this scenario, friction is present between the block and the surface it is resting on. This force must be overcome by the applied force of the light cord in order for the block to move. Friction also plays a role in determining the acceleration of the block, as it can decrease the overall force acting on the block.

How does the mass of the block affect its motion?

According to Newton's second law, the mass of an object affects its acceleration when a force is applied. In this scenario, a lighter block will accelerate more quickly than a heavier block when pulled by the same force. This is because the lighter block has less mass, so the force has less mass to accelerate. However, the overall motion of the block will still follow the same laws regardless of its mass.

Can the laws of motion be applied to objects in different environments?

Yes, the laws of motion can be applied to objects in any environment, as long as the forces acting on the objects are known. These laws are universal principles that govern the behavior of all objects in motion, regardless of their location or surroundings.

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