Laws of Motion | Learn About Newton's Laws

[haha1234]

The photo shows below is my attempted solution.
Is there any mistake so I cannot get the correct answer?

 

[Andrew Mason]

The photo shows below is my attempted solution.
Is there any mistake so I cannot get the correct answer?

You have the right idea. But you have not taken into account the fact that the mug is moving during this process. So how far does the table cloth have to move?

AM

 

[haha1234]

I still cannot figure out the right answer

 

[Tanya Sharma]

I cannot understand your working .

Please answer the following questions:

1) What is the acceleration of the mug ?
2) What is the relative acceleration of the cloth with respect to the mug?
3) How much time does it take to pull the cloth completely out from under the mug?

 

[haha1234]

I cannot understand your working .

Please answer the following questions:

1) What is the acceleration of the mug ?
2) What is the relative acceleration of the cloth with respect to the mug?
3) How much time does it take to pull the cloth completely out from under the mug?

(1)I don't know if it is correct.
I found the acceleration of the mug is f=ma→0.1=0.2a→0.5ms^-1
(2)3-0.5?
(3)I don't know.

 

[Tanya Sharma]

(1)I don't know if it is correct.
I found the acceleration of the mug is f=ma→0.1=0.2a→0.5ms^-1

Correct...except the units are ms^-2

(2)3-0.5?

Correct...So the relative acceleration is 2.5ms^-2

(3)I don't know.

Okay...First answer this - What is the distance cloth has to move with respect to the mug so that the cloth is completely out ? (Read the question carefully ,you may get the answer in question itself )

 

[haha1234]

Correct...except the units are ms^-2



Correct...So the relative acceleration is 2.5ms^-2


Okay...First answer this - What is the distance cloth has to move with respect to the mug so that the cloth is completely out ? (Read the question carefully ,you may get the answer in question itself )

I don't know.
I still cannot understand and still think that the solution is as follow.- -"
0.3=0.5(3)t^2
T=0.447s

s=ut+0.5at^2
=0.5X0.5X0.447^2
=0.05m
However the correct answer is 0.06m

 

[Tanya Sharma]

0.3m?

Correct...

So the cloth has to move .3m with respect to the mug such that it is completely out.The relative acceleration of the cloth is 2.5ms^-2 .

Now use the kinematics equation x=ut+(1/2)at² ,where u=0 ,x=0.3m and a=2.5ms^-2 .

This will give you the value of 't' i.e time it takes to pull the cloth completely out from under the mug .

What do you get ? Let the answer be in square root only.

 

[haha1234]

Correct...

So the cloth has to move .3m with respect to the mug such that it is completely out.The relative acceleration of the cloth is 2.5ms^-2 .

Now use the kinematics equation x=ut+(1/2)at² ,where u=0 ,x=0.3m and a=2.5ms^-2 .

This will give you the value of 't' i.e time it takes to pull the cloth completely out from under the mug .

What do you get ? Let the answer be in square root only.

Thank you!
I can get the correct answer now.

 

[Tanya Sharma]

Thank you!
I can get the correct answer now.

:thumbs: