newtons laws contradiction question
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Originally posted by CaiHongRainx:
LOL is this the explaination? These 2 forces arent opposite to each other, which N3L say that the forces must be equal and opposite. So its 0N.
Wrong.
For an object in free fall, it is accelerating downwards at 10m/s2. This means it's downwards force must be it's weight. If there is any upwards contact force, that means that the acceleration is less than 10, which means the object isn't in free fall anymore.
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So, is this gavitational force of the earth or due to atmospheric density and particles etc that generated this force. In the water, the force is not the same. In the dead sea, its float. In space, we knew that it also has some degrees of force that resulted in object floating rather than moving upwards towards the peak of the solar system and can it crosses over to other solar system. The upward arrows are signifying the "forces" and something to note is the area and perimeter of the object that will contribute the way it goes downward. Which mean, if the object of a rectangle falls down directly, the arrows(equal) of upward and downward forces on the rectangle is equal, why isn't the rectangle object landed squarely on the surface.
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my god... contact force and gravitational force can never be action reaction pair because they're different fundamental forces!
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ME too same quires if you know answer means please upload that.......
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Originally posted by Amitayus48:
So, is this gavitational force of the earth or due to atmospheric density and particles etc that generated this force. In the water, the force is not the same. In the dead sea, its float. In space, we knew that it also has some degrees of force that resulted in object floating rather than moving upwards towards the peak of the solar system and can it crosses over to other solar system. The upward arrows are signifying the "forces" and something to note is the area and perimeter of the object that will contribute the way it goes downward. Which mean, if the object of a rectangle falls down directly, the arrows(equal) of upward and downward forces on the rectangle is equal, why isn't the rectangle object landed squarely on the surface.
Sorry, I don't understand your English.
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Originally posted by wayne471:
my god... contact force and gravitational force can never be action reaction pair because they're different fundamental forces!
This is correct.
For gravitational force, the g-force acting on an object by the Earth and the g-force acting by the object on the Earth is an action-reaction pair.
However, the 2nd portion is usually beyond most O level students as it is not in the syllabus.
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Originally posted by eagle:
This is correct.
For gravitational force, the g-force acting on an object by the Earth and the g-force acting by the object on the Earth is an action-reaction pair.
However, the 2nd portion is usually beyond most O level students as it is not in the syllabus.
Another way to look at it is the action-reaction pair never acts on the same body. Weight and normal reaction act on the same object so its totally wrong. How's that?
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Originally posted by wayne471:
Another way to look at it is the action-reaction pair never acts on the same body. Weight and normal reaction act on the same object so its totally wrong. How's that?
Correct as well. We have to know that action-reaction pairs have the following properties
1) equal in magnitude
2) opposite in direction
3) same nature of force
4) acting on different bodies -
then y would it be 0N for contqct force? i thought the hand which is travelling with the same acc would also exeet a contact force on the book? thanks n sorry cos im using my phone to write this n there isnt auto correct
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Chong Mei Kao Tim ?!!
In my opinion, please help for those who are current or had studied this subject (Applied Mechanic).
Please do not troll.
New guys will only get more confuse. You can see SgStudentStressed's questions that he is way off in his understanding. Therefore ask a lot of "unrelated" questions.
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Originally posted by SgStudentStressed:
then y would it be 0N for contqct force? i thought the hand which is travelling with the same acc would also exeet a contact force on the book? thanks n sorry cos im using my phone to write this n there isnt auto correct
You have to look at the free body diagram again.
What is the resultant acceleration? And hence what is your resultant force?
Have you gotten your tutor to teach you the free body diagram yet? -
yes forces acting on the job onli. so if the object is on the hand and travelling with 10m/s2 means that there is a resultant force downwards n 0N contact force or else it would be balanced n not move. but then since the hand is touching the book then y wouldnt there be a contact force. or is it onli when it doesnt move then it causes a contact force? thanks
as for punggolmeegoreng, i am sec 3 taking pure physics so i only touched a bit of contact force n other stuff as most of the stuff i learnt is based on the second law which is net F=ma
thanks eagle
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To : SgStudentStressed
I wanted to pitch in to help. But I guess I may confuse you even further.