0
votes
0answers
21 views

What is the frictional coefficient between blocks? [closed]

1) 30 N 2) 27 N 3) 25 N 4) 48 N This question came in one exam. I have many confusions : 1) How the question is talking about minimum force? If I apply very large force then obviously they won't ...
3
votes
0answers
28 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
votes
0answers
13 views

Falling rod on a frictional surface [duplicate]

Suppose there is a rod balancing on a table.the rod tips vertical and begins to fall. derive an equations of normal force and friction force on the bottom as a function of angle between the rod and ...
1
vote
1answer
50 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
43 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
81 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
66 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
3answers
252 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
262 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
84 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
36 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
66 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
78 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
424 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
57 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
59 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 ...
-6
votes
1answer
169 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
53 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
47 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
419 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
124 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
96 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
57 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
93 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, ...
-1
votes
2answers
176 views

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

Explain what is limiting force of static friction.
-1
votes
1answer
61 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
70 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
227 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
39 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 ...
-1
votes
1answer
3k 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
99 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 ...
0
votes
1answer
71 views

Interpretation of Free Damped Vibrations

I'm studying vibrations; so I'm using Beer-Johnston-Cornwell Dynamics book. I am worry about the equation for Underdamped Vibration, which in the book it is: $$x_{(t)}=x_0e^{-\lambda ...
2
votes
0answers
172 views

Loop-the-Loop with Friction [closed]

Let's consider a track that begins vertically becomes a 450 degree loop, and level off. (See diagram) We drop a block from height $H$ that falls and goes around the loop. Ignoring air resistance, ...
1
vote
2answers
948 views

Finding max height of a mass lanuched by a spring?

I have the following problem on my homework. The actual problem has numbers, but I figure using symbolic notation will help me understand the concept in the long run. A block of mass $M$ is launched ...
3
votes
3answers
188 views

How can a block which is not receiving the direct force have a greater acceleration?

I solved it like this: $$F(\text{st max})=5\text{ N}$$ For the top block, $$\begin{align} 6\text{ N} - 5\text{ N} &= 1a \\ a &= 1\ \mathrm{m/s^2} \end{align}$$ For the lower block, the ...
0
votes
3answers
389 views

Resistive force proportional to velocity

Find the displacement and velocity of horizontal motion in a medium in which the retarding force is proportional to the velocity. I kind of understand how to do this problem. We know that the ...
1
vote
0answers
214 views

Forces on two boxes

This is a problem from my problem sheet but we haven't yet covered the material or received our books. There is a small box of mass $m_{1}$ resting on a plank, of mass $m_{2}$ and length $L$, which ...
2
votes
2answers
183 views

Would box on the floor rotate?

There is a floor that friction is proportional to its velocity (like $F=-kv$) and there is a box with its width as $l$ and its height as $h$. (you may assume that $l$ is longer than $h$). It is on the ...
1
vote
1answer
603 views

Calculating the frictional force

Here's my problem and the work I've done. The time is already past for me to submit the answer, but I want to know where I went wrong and why I was wrong. The 2-kg box slides down a vertical wall ...
3
votes
5answers
335 views

Ball rolling into a bowl - where is its maximum KE (speed)… given there is friction. See diagram

Please examine this diagram and answer the apparently trivial questions. I am particularly interested in reasoned answers for part (a)(ii) - where is the maximum Kinetic energy? I say it is at B ...
0
votes
2answers
642 views

Friction problem having two blocks on separate inclined planes connected by a string

This is a question I found in my old high-school textbook(I'm revising the topics for a course).Two blocks A and B of masses $1kg$ and $2kg$ are placed on a fixed triangular wedge by a massless ...
1
vote
1answer
206 views

Circular motion question

(Q) Find the maximum speed at which a truck can safely travel without toppling over, on a curve of radius 250m. The height of the centre of gravity of the truck above the ground is 1.5m and the ...
1
vote
2answers
672 views

Object with friction in circular motion caused by a string

A physics problem in my textbook reads: A 0.40kg ball, attached to the end of a horizontal cord, is rotated in a circle of radius 1.3m on a frictionless horizontal surface. If the cord will ...
5
votes
0answers
105 views

Particle sliding on a semisphere - solving the differential equations analytically [closed]

I have the following problem: A particle of mass $m$ is at rest at the top of a semispherical surface of radius $R$. After an impulse, it starts to slide along a meridian with speed $v_0$. The ...
1
vote
1answer
237 views

What is the friction between cylinder and wall (ground)?

A hollow cylinder (radius $R$) is rolling against the wall at angular speed $\omega$. The coefficient of friction between the cylinder and the wall(ground) is $\mu$. After how many rotations the ...
2
votes
2answers
378 views

Falling chain with friction

I really need some help with a physics problem, and I guess my doubt is more conceptual, than question based. But still, let me pose it to you: A uniform chain of mass $M$ and length $L$ lies on ...
5
votes
3answers
685 views

Why do we take small steps while walking on ice?

When we walk on ice we should take small steps. Small steps ensure: a.)larger friction. b.)small friction. c.)larger normal force. d.)smaller normal force. The correct ...
3
votes
2answers
434 views

A block on a wedge

The system is as follows - Friction exists only between the 2 blocks. I am trying to find out the accelerations of $m_1$ and $m_2$. Let $a_2$ be acceleration of $m_2$, and $a_x$ and $a_y$ be the ...
-2
votes
1answer
76 views

A question about speed [closed]

A object with mass 0.5 kg slides in straight line for 200 m, where the friction act on it is 0.4 times the normal reaction acting on it. Find its initial speed. I let $u$ be the speed. ...
-3
votes
1answer
265 views

Question on static friction [closed]

This is the question, and the answer is given as 2). Now my basic doubt is, are they asking us the direction of the total contact force on the object by the floor? Or, are they asking the direction ...