All Questions
81
questions
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1
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56
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Why is hookes law not obeyed in vertical circular motion? [closed]
We know that $$T=-kx=-k(R-L)$$where $L$ is the natural length of string, so the tension force must be constant. but in vertical circular motion the tension force is not constant (via analysis of ...
- 89
0
votes
1
answer
93
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Does Weighing machine measure normal force or gravity or both?
A weighing machine measures the normal force applied by an object.
However 2 forces act simultaneously on the machine ( normal and mg )
Under normal conditions (a=0) N=mg .
So this would mean that a ...
-4
votes
1
answer
64
views
Find the acceleration of a block sliding down on an accelerating inclined place [closed]
I don't understand the solution provided in the image. Using Newton's second law for forces along the x-axis (parallel to the inclined plane), shouldn't the equation be $ma = mg\sin \theta+ mb\cos \...
0
votes
0
answers
69
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Dynamic equilibrium of planets
We can describe statical equilibrium ( forces, moments ) in a cuboid $$ \Sigma F_x=0,\Sigma F_y=0,\Sigma F_z=0~$$ In dynamics can we describe similar dynamic equilibrium within an inertial ...
- 1,032
1
vote
2
answers
252
views
Chain hitting a scale
a standard problem in textbooks is to calculate the force of a chain of length $L$ as it hits a scale and has fallen a length $x$. It is found to be $3gMx/L$ by the gravitational force $xmg/L$ and ...
- 139
2
votes
6
answers
879
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If there is no gravitational force on the earth (i.e. acceleration due to gravity is 0m/s^2), will bodies in contact still experience a normal force?
My question arises from this post by Ashish Arora, where he asks: "If $g$ becomes zero suddenly, a body at rest on a fixed table will start moving away from it."
In the above question $g$ is ...
- 123
1
vote
6
answers
541
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How does unbalanced force ever create? [duplicate]
This question rather seems elementary but has been bugging me for a while! How does even unbalanced forces create? The main driving force of this question is Newton's third law
Let's take Free Fall:
...
- 648
0
votes
1
answer
57
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How can vertical force due to gravity vary in a column?
Non-physicist asking.
Suppose I have a tall building or column. The downward pressure on the walls near the foundations is intuitively greater than at the top of the building. Yet according to Newton, ...
- 3,006
-1
votes
2
answers
61
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Theoretical question about elevators [closed]
Question
Imagine we put a bascule/weighing machine in an elevator, and that elevator starts to acelerate downwards with a certain aceleration that we don't know of. Is it true that the bascule will ...
user348118
0
votes
3
answers
547
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Why is the normal force always perpendicular to the surface rather than opposing the force?
In the classic "box on a ramp" example, how does it know which way is perpendicular? If the normal force was opposite of gravity, the force being applied, it would still constrain the box ...
1
vote
1
answer
89
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In simple terms, why does a skateboard slide in the opposite direction of its falling rider?
I would like to have a better understanding of something I’ve observed:
If I stand on a skateboard at rest, there is no movement.
If I lift my left leg, my body of course starts to fall to the left, ...
- 11
2
votes
1
answer
130
views
How is the weight of a hanging block communicated to a scale?
I read in a physics text (Tipler, Physics for Scientists and Engineers, 5th ed.) that if we have a scale, and on the scale is a hollow box of mass $M$, and inside the box is a block of mass m hanging ...
- 693
1
vote
1
answer
43
views
What is opposite to $\mathbf{w}_\parallel$ in a FBD of a box on a ramp?
I tried doing research on this but to no avail so my question is this:
If the normal force of an object with mass $m$ on a ramp inclined with angle $0<\theta<90^\circ$ is equal and opposite to ...
0
votes
2
answers
124
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If a box is at rest on an inclined plane, as you increase $\theta$, $F_n$ decreases but $F_f$ increases? [closed]
If $F_f =\mu× F_n$, then why does $F_f$ increase when $F_n$ decreases?
[Here $F_f$ is frictional force, $F_n$ is normal force and $\mu$ is coefficient of friction]
- 65
-3
votes
1
answer
154
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Accelerating downwards faster than gravity
What would happen if you were in an elevator that was falling downwards with a acceleration and a>g? I found an answer on this site that said that you'd hit the ceiling of the elevator. I ...
- 801