# Tagged Questions

The resistance a surface or object encounters when moving over another.

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### Does really a spring compresses placed between two blocks when one block is given force on a frictionless surface?

When Spring is placed between two bodies on a frictionless surface it gets compressed when one block is given kinetic energy as told by my physics teacher. But it should not compress as there's no ...
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### Sliding and rolling friction

I heard that friction depends only on the normal force but not on the contact area. Let's take a cube and a sphere which are of same weight (then normal force will also same ) but the force needed to ...
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### Friction between needle and bearing

I have a question about friction and its effect on materials. Please forgive my long description of the problem. I have made a Device that is designed to slowly oscillate a magnetically suspended ...
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### Calculating constant velocity from friction [closed]

I'm unsure if my Book is wrong. Either way, we send a pinball through a cylinder filled with oil, the forces that apply are. Fpinball = 15,8 ∙ 10^−6 ∙ 9,82 = 5,69 ∙ 10^−5N Foil = 𝜌 ∙ 𝑔 ∙ 𝑉 = 0,...
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### A false proof of drag force being conservative

Consider a particle moving along some trajectory in the $x$-$y$ plane, in a viscous medium. Then its equation of motion is given by: $$\mathbf{F}_d = - b \mathbf{v} .$$ it's well-known from the ...
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### How does magnetic field gets generated by friction between high temperature molten metallic cores?

I was watching "Strip the cosmos" show on Discovery science channel last day and they explained that earth produces magnetic field due to rubbing of the two concentric cores, both the molten metal ...
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### Finding the coefficient of friciton [closed]

I'm asked to find the coefficient of friction before the bar starts sliding. Here is my solution -> ∑M = 0 -mg * 1.4863 + 1.8159*T = 0 (T*1.8159) i found by using a cross product ( -2.9726i+ 2....
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### work done in observer frame

I had a few questions. 1) Is work done independent of the refrance frame? 2) Suppose a cart-A with rough surface is accelerating with an acceleration a and another cart-B with acceleration b. Now to ...
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### Must one include friction and gravitational force in the work term?

Example problem: "A sled has an initial velocity up a ramp of 5 m/s, the ramp has an angle of 20 degrees to the horizontal, and the coefficient of dynamic friction between the sled and the plane ...
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### Accelerated pure rolling and friction

I know that if a body is pure rolling with no acceleration then friction acting on it is zero. But what about if the CM has an acceleration? Then can we say that friction is present? Suppose that ...
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### In practical, how to find the friction of rubber vs plastic? [duplicate]

I did an experiment. The experiment was to use a gripper which had rubber fingers to grip a plastic rod which attached to a mass. After that I had a linear motor to move the gripper. What I wanted ...
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### Sliding Wine Glass [duplicate]

Earlier today, I came across a strange phenomenon involving a just-washed wine glass and a countertop. The gist of it is: when you place a warm wine glass upside-down on the wet countertop, it starts ...
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### Simultaneous: static friction and acceleration

I need help thinking about two events happening simultaneously. I have a heavy block on a surface with static and kinetic coefficients of friction, though they are unknown. The block is connected to ...
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### Circular Motion and Simulated Gravity

People have proposed that a spinning cylindrical shape could be used to simulate gravity. Will gravity be simulated if the cylinder is frictionless? My brain can't seem to wrap around the idea that ...
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### The role of mass in the tablecloth trick

Apologies if this has already been answered, but I have a question about the role of mass in the classic tablecloth trick, where the demonstrator pulls the tablecloth out from underneath a set of ...
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### Using resultant vectors to calculate how long it takes to travel a distance [closed]

A box of books weighing $320 \;\mathrm{N}$ is shoved across the floor of an apartment by a force of $569 \;\mathrm{N}$ exerted downward at an angle of $36.5^\circ$ below the horizontal. The ...
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### Zero gravity means zero friction?

The frictional force acting on a body placed on a horizontal plane is $F=\mu{R}$ where $R$ is the normal reaction and is equal to weight of a body in this case. And $\mu$ is the coefficient of ...
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### If a body slides down a frictionless inclined plane what will be the net normal force?

If a body(m) slides down a frictionless inclined plane (M), will the net normal force between the ground and the inclined plane be (M+m)g ? I feel it should be less than (M+m)g. This is because one ...
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### How to develop the static and kinetic friction formula? [duplicate]

How do you end up with the formula for Amontons' first law of friction? ($F_s = \mu_s \times N$) or ($F_k = \mu_k \times N$). I know how to use the formula. Now I need to know how to get to it.
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### Static vs. kinetic friction and the “normal-force” considered

Consider two cases. First, we have a box that a person applies a force to (say to the right). The force of friction (static) is then directed to the left. Second, say that the box is moving at ...
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### Is cause of this equilibrium - tension or friction?

This is a very odd problem which I have. As you can see in the diagram, the string is taut. So, if there was no friction you could clearly say that tension is balancing it or if there was no tension ...
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### Why does a block 2 on a oscillating block 1 start sliding at the maximum acceleration?

A block of mass $m_{1}$ is oscillating horizontally with another block on it of mass $m_{2}$. There's friction "k" between both blocks, so the thing is why the second mass starts sliding at the ...
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### Terminal velocity and distance traveled with constant but limited power

I'm trying to model how far to move an object over time according to a power applied resisted by friction. So maybe... an object accelerates at a certain rate until the power provided can no longer ...
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### Why consider only $x$ component of accelerating block pulled by cord at an angle?

A $5 \, \text{kg}$ block is pulled along a horizontal frictionless floor by a cord that exerts a force $F=12 \, \text{N}$ at an angle $\theta = 25 \, \text{deg}$ above horizontal. What is acceleration ...