0
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0answers
25 views

How torque and friction cause wheel to roll

I apologize if this question has been answered before, but I did not find the explanation that I needed. If a torque is applied to a wheel situated on a frictional surface, what forces cause the ...
1
vote
0answers
38 views

Tension Problem: Solve for T for two sliding blocks connected by a string [on hold]

The problem: Two blocks made of different materials connected together by a thin cord, slide down a plane ramp inclined at an angle θ to the horizontal as shown in the figure (block B is above ...
1
vote
1answer
38 views

Static and kinetic friction [on hold]

Say you have block1 on top of block 2 and the whole system is accelerating toward the right at a certain acceleration. Due to inertia block 1 wants to move backward to the left so there has to be a ...
0
votes
0answers
15 views

Elementary thermodynamics problem? [on hold]

The maximum height reached by an aluminum rocket is $115\,\text{km}$. Upon reaching Earth, it is traveling with a speed of $1500\, \text{m}/\text{s}$. if 50% of the heat generated by friction with the ...
1
vote
1answer
20 views

Calculate coefficient of friction from deceleration with and without conservation of energy

How can I solve the following problem? A block that moves at the speed of 120 cm / s keep going for 70 cm before stopping. What's the coefficient of friction between block and table calculated ...
3
votes
1answer
86 views

Could $\int (\ddot\phi + \mu\dot\phi^2)d\phi$ ever be negative? How to show it?

I am working on the following problem: Given a mass $m$ at rest at the base of an incline surface shaped like 1/12th of a circle with radius $R$. The mass is pulled up the incline by a rope that ...
1
vote
2answers
41 views

Finding coefficient of friction between block and plane [closed]

An inclined plane makes angle $\theta$ with horizontal. Upper half plane is perfectly smooth where as lower half is rough. The block of mass m starts sliding from top. If the block again comes to rest ...
1
vote
1answer
44 views

Modeling a stool with three legs pushed on one leg

If a stool with three legs is pushed (horizontally) on one leg in the direction of the axis passing through the other two legs, it starts both moving and rotating. Is it correct to assume 1/3 of ...
1
vote
1answer
93 views

Moving wedge and pulley system

A wedge of mass $M$ rests on a rough horizontal surface with coefficient of static friction $\mu$. The face of the wedge is a smooth plane inclined at an angle $ \alpha$ to the horizontal. A mass ...
1
vote
0answers
30 views

Inclined plane problem with friction [closed]

A block of mass 6.0 kg slides from rest at a height of 2.0 m down to a horizontal surface where it passes over a 1.5 m rough patch. After crossing this patch it climbs up another incline which is at ...
0
votes
2answers
38 views

Work done by a frictional force on a cylinder

A cylinder of mass $m$ and radius $R$, is rolled on surface with coefficient of kinetic friction $\mu_{k}$ about the axis passing through the center and parallel to the surface, with initial ...
0
votes
1answer
35 views

Kinematics - moving body [duplicate]

If I have an inclined plane, which has acceleration $\alpha$, will a block placed on the inclined plane slip back with the same acceleration? (considering that the surface is frictionless)
1
vote
1answer
99 views

Block and Pulley Problem with Friction [closed]

1.) What is the acceleration of the hanging mass? (Indicate the direction with the sign of your answer.) 2.) Determine the tension in the cord. (Indicate the direction with the sign of your ...
1
vote
0answers
54 views

Friction force problem for a 4 wheel drive Car [closed]

The car is a 4 wheel drive in equilibrium, the car doesn't touch the ground with the front wheel (A) but is in contact in B with the sidewalk (the sidewalk has a hight equal to $h$), the friction ...
1
vote
3answers
251 views

Why is using Newton's First Law failing me?

A factory worker pushes a 29.7kg crate a distance of 5.0m along a level floor at constant velocity by pushing downward at an angle of 32$^\circ$ below the horizontal. The coefficient of kinetic ...
1
vote
1answer
32 views

Clarification what exactly this question wants regarding force [closed]

I would like to ask you if the question asked What is the minimum force parallel to the plane, which can be prevent the block from slipping down the plane? I just did the calculation and and ...
0
votes
3answers
56 views

Solving for Normal Force

I'm working through The Nature of Code, which is an awesome book, lots of fun. I've come across Exercise 3.13 and I'm not sure how to solve it. I'm assuming that the force of gravity and the force of ...
0
votes
1answer
45 views

graphing velocity and time (v-t graph) [closed]

The question goes like this: If we push a body shortly uphill and it gets a starting velocity of $v \ ms^{-1}$,the coefficient of friction between the body and the surface is constant, represented by ...
1
vote
2answers
102 views

Why neglect friction when computing torque?

There is a block of wood on a plank, with friction, and the block is moving down with uniform speed. They are asking what is the torque acting through the center of the block. My doubt is that ...
1
vote
0answers
56 views

Uniform Circular Motion with Banked Road and Car [closed]

In Uniform Circular Motion, if a car is rounding a curve at a certain speed, and the angle of the road allows the car to drive around at that speed, that speed is called the "design speed." If the ...
1
vote
1answer
193 views

Mechanics question - ladder leaning against a wall

I am struggling with part a) of this question: Here is the solution: In part a) they prove that $F \leq \mu R$ is false for this system. So as $F$ is neither less than nor equal to $\mu R$ it ...
3
votes
0answers
40 views

How much weight is lifted from each side? [closed]

I don't know the math to do this, so I am asking here if someone can work this out with all of the details I'm providing. Total mass EST.: 2,400 lbs. Length from front to back: 14 feet 6 inches. ...
1
vote
1answer
60 views

High-School Physics with inclines [closed]

The figure below shows two blocks with a rope that runs over a pulley. The mass of $m_2$ is 5.0 kg and the incline is 35 degrees. The coefficient of static friction between $m_1$ and the inclined ...
0
votes
1answer
111 views

Finding friction forces of stacked boxes on a table

Consider the following system. The given friction coefficients are for static. Let $g=10$ (meter per square second). If the $F(t)=10t$, for example, determine the friction forces $f_{AB}(t)$ ...
2
votes
1answer
210 views

How is circular motion possible on a banked road when there is no Friction?

It is given here that the maximum safe speed of a vehicle on a banked road having coefficient of friction $0$, is $V =\sqrt{R g \tan \theta}$, where $\theta$ is the angle of banking. I can't ...
1
vote
1answer
105 views

Calculating the time to stop a wheel with friction [closed]

I'm trying to solve the following problem, but i have no idea how to begin. A wheel of mass $M$, radius of gyration $k$, spins smoothly on a fixed horizontal axle of radius a which passes through ...
1
vote
4answers
365 views

How long does it take for an electric car to go from 0 to 60 mph?

I found the freefall motion equation which describes terminal velocity of a falling body, but I can't find a similar equation for a vehicle subject to constant traction force, so I tried determining ...
4
votes
4answers
1k views

Blocks stacked on an incline connected by rope around pulley

Two objects A and B, of masses 5 kg and 20 kg respectively, are connected by a massless string passing over a frictionless pulley at the top of an inclined plane, as shown in the figure. The ...
0
votes
1answer
165 views

Help understanding a potential energy problem [closed]

Apologies if the following problem does not seem to involve potential energy, it is a homework problem that is labeled under the potential energy chapter. Question While a roofer is working on a ...
2
votes
0answers
58 views

Can I use the reduced mass principle in a spring-damper system?

http://hyperphysics.phy-astr.gsu.edu/hbase/orbv.html#rm I want to know, if I can use the reduced mass principle to solve a two object spring-damper system. In the books and webpages that I have ...
0
votes
0answers
321 views

Damping ratio and damping coefficient of two objects connected by spring

There are two objects m1 and m2 connected by a spring and a viscous damper (e.g car body and wheel connected by spring) From wiki: $\zeta ={c \over 2{\sqrt {mk}}}$ ζ is damping ratio, c is damping ...
0
votes
1answer
140 views

Contradiction regarding friction of a rolling cylinder in an inclined plane

I came upon this while wondering whether the friction of a rolling cylinder on an inclined plane depends on the value of friction coefficient. now, $$f\leqq\upsilon N$$ Again after calculating I ...
1
vote
1answer
1k views

Calculate work done in an inclined plane [closed]

How can you calculate the work done by a force (of unknown quantity) exerted on a 10kg block on an inclined plane. The force is pointing upwards and parallel to the incline (which is inclined 30 ...
1
vote
1answer
86 views

Angular Velocity after a frictional impulse

I am modelling 2D physics collision into simulations. In Physics for Game Programmers, Grant Palmer book, the velocity Vn1 after collision is mentioned to be independent of the friction coeff. ...
-3
votes
1answer
67 views

Forces: why are the theta's equal?

I found this figure in my physics book, the task says that the incline got a angle of theta. How do figure out that the gravity and the y-axis got the same angle as the incline? There is no ...
-5
votes
1answer
482 views

Is it possible to find the coefficient of friction without frictional force? [closed]

I am working on the following problem: The braking acceleration for a car based on data in a driver’s handbook is –12.2 m/s2. If the car has a mass of 925 kg, find the frictional force and state the ...
-1
votes
1answer
72 views

What is the frictional force of this car? [closed]

The breaking acceleration for a car is $-12.2\frac{m}{s^2}$. The car has a mass of 925kg. I want to find the frictional force. Here is what I have so far: $$\Sigma\vec{F} = m\vec{a}$$ $$\Sigma\vec{F} ...
1
vote
2answers
61 views

Position with respect to time with friction

I'm interested in equations of motion when friction is present for a little graphical side project I am working on. I'm really rusty with physics, so I apologize if this is a basic question or doesn't ...
0
votes
2answers
922 views

What is the direction of static friction?

Note: My question is duplicate of the following Direction of friction when a car turns Why does friction cause a car to turn? I've gone through many related questions especially the first. As ...
0
votes
1answer
166 views

Block Sliding Down a Plane (Perpendicular Velocity)

I'm having trouble understand the concepts for this problem. Here's the problem: A block is placed on a plane inclined at angle $\theta$. The coefficient of friction between the block and the ...
-1
votes
2answers
113 views

Friction acting on mass on string

Assume we have some stationary point mass that would slide, if not for some coefficient of friction, along a light, inextensible string, attached to two points at different heights. Considering ...
0
votes
1answer
66 views

Find the force used to press a book against a leaned desk so it doesn't slip

I know there are several threads concerning this issue, but none of it helped me, so I decided to open a new one. So, the task is to find a force $F_{\mathrm{push}}$ on a desk which is leaned for an ...
0
votes
1answer
111 views

How do I find angular and linear velocity after normal force and “infinite” friction force?

Look at this picture: http://i.imgur.com/mY8ShkV.png Here we have a ball resting on top of a platform (the contact point is marked red). I know the normal vector (marked green). I also know the mass, ...
-2
votes
2answers
467 views

Why is static friction called self adjusting force? [closed]

Explain what is limiting force of static friction.
-1
votes
1answer
69 views

friction between 2 bodies [closed]

There is a plank on which a block is kept. the block is given some velocity. Now if there is friction between block and plank it will act opposite to it's velocity for sure. but the plank is free to ...
0
votes
0answers
80 views

Finding kinetic friction coefficient

A box is thrown up an incline with degree $\alpha$. the kinetic-friction coefficient is $\mu_k$. the body returns back to its start point. a. prove ...
0
votes
2answers
251 views

Conservation of Angular Momentum and linear velocity

I have a problem where a cylinder is moving on a horizontal surface, starting with velocity $v_0$. It is given that its radius is $10\text{cm}$, its mass is $200\text g$ and the coefficient of ...
-3
votes
1answer
43 views

Acceleration on an inclined rail [closed]

I have to use $\vec{P}+\vec{R_N}+\vec{F_f}=m\vec{a}$ with $\|\vec{F_f}\|=\mu\|\vec{R_N}\|$ to express the acceleration as $$a_{x'}=g\sin\alpha(1-\frac{\mu}{\tan\alpha})$$ The configuration is (sorry ...
0
votes
1answer
4k views

Rope tension between two objects [closed]

Let me explain the picture just to make sure. Object with mass 2 kg is being pulled with a force of F = 14.4 N. The whole system has an acceleration of a = 2.8 m/s^2. The friction coefficient ...
0
votes
3answers
103 views

$P\sin(\alpha)$ and not $\sin(\alpha)/P$?

Why is the force parallel to the surface that pushes the object $P \sin(\alpha)$ and not $\frac{\sin(\alpha)}{P}$? I didn't understand when they showed me it. can someone give me an answer in full ...