Tagged Questions
0
votes
1answer
21 views
Question on friction
Please look at the figure carefully. The question is written, and one has to match the two columns 1 and 2 given under "choices and explanation". Please tell me if I am really wrong, i.e. would you ...
1
vote
1answer
62 views
Friction on a conveyor belt
I was surfing through an Olympiad paper and I was caught with this question.
A block of mass 1 kg is stationary with respect to a conveyor belt that is accelerating with $1\, \tfrac{m}{s^2}$ ...
0
votes
0answers
19 views
newton's laws - involving block and conveyor belt [closed]
i was surfing through a physics book when i encountered this problem-
A block of mass 1 kg is stationary with respect to a conveyor belt that is accelerating
with 1 m/s^2 upwards at an angle of ...
-1
votes
1answer
53 views
Comparing Static Frictions
In this figure, which of the static frictional forces will be more?
My aim isn't to solve this particular problem but to learn how is static friction distributed . Since each of the rough-surfaces ...
0
votes
0answers
50 views
Work And Energy Question [closed]
$H = 3\text{ m}$,$m=2\text{ kg}$
The right side is rough.
I want to figure:
what is the coefficient of friction $\mu$?
How high and exceed the maximum return on the plane right body?
I know ...
-2
votes
0answers
69 views
Man ,Pulley, block system? [closed]
In the figure $m_{A}=m_{B}=m_{C}=60 kg$. The coefficient of friction between $C$ and ground is $0.5$, $B$ and ground is $0.3$, $A$ and $B$ is $0.4$. $C$ is pulling the string with the maximum possible ...
2
votes
1answer
126 views
Two masses attached to a spring
I'm trying to understand the solution of the following problem.
Two masses $m_{1}$ and $m_{2}$ slide freely in a horizontal frictionless track and are connected by a spring whose force constant is ...
3
votes
3answers
65 views
Friction on roads
I have a question with which I am having trouble.
A 71m radius curve is banked for a design speed of 91km/h. Given a coefficient of static friction of 0.32, what is the range of speeds in which a car ...
0
votes
1answer
60 views
How to find work done due to friction [closed]
The force F=40N is applied on a 10kg block at an angle of 36 with the horizontal. The block moves a distance of 15m. If the surface is frictionless. If the coefficient of kinetic friction is 0.25, ...
1
vote
2answers
165 views
Projectile Motion with Drag
The overall goal is to write a Mathematica program that will compute the launch angle that will yield the greatest range with using [RandomInt] function, but I was having trouble with the physics.
In ...
0
votes
0answers
56 views
Work done by friction (homework) [closed]
A 40 kg case is pushed across a floor at a steady speed of 1.5 m/s. When the pushing stops, the case slides a further distance of 1.2m before coming to rest. Calculate the frictional force acting on ...
0
votes
0answers
46 views
Work, energy and friction [closed]
A car loaded with bricks has a total mass of 18kg and is pulled at a constant speed by a rope. the rope is inclined 30 degrees with above the horizontal, and the cart moves 20.0 m on a horizontal ...
2
votes
1answer
280 views
Static Friction in Free Body Diagram (FBD) of Car parked on Incline
I'm working on a sample problem and it asks on how steep of an incline can a car park? From what I learned the friction is in the opposite direction if there was motion in said friction-less ...
0
votes
1answer
109 views
Determining the frequency of a ruler laying on two spinning cylinders [closed]
I am stuck on this homework problem. Any help would be appreciated, even if it's a push in the right direction.
A ruler of mass m = 75g and L = 3.0 meters is placed so that it is exactly balanced ...
1
vote
2answers
174 views
Preventing a block from sliding on a plane (with friction)
Assume a small square block $m$ is sitting on a larger wedge-shaped block of mass $M$ at an upper angle $\theta$ such that the little block will slide on the big block if both are started from rest ...
4
votes
3answers
179 views
How can a vertical force cause motion at an angle?
I just started learning physics 3 days ago and am having trouble understanding what I am doing wrong. Can someone please explain my error(s)? Thanks!
We have a 1kg object on a plane at a 30 degree ...
1
vote
0answers
475 views
Newton's second-law word problems with coefficient friction [closed]
Here is an example problem:
A sled of mass 50kg is pulled along a snow-covered, flat ground. The static coefficient of friction is 0.30, and the kinetic coefficient friction is 0.100. What force ...
1
vote
0answers
79 views
What is the angle of the string with the vertical?
A heavy uniform sphere of radius $a$ has a light inextensible string
attached to a point on its surface. The other end of the string is
fixed to a point on a rough vertical wall. The sphere ...
0
votes
2answers
92 views
Energy problem: What's wrong here?
A car ($m=540\,\text{kg}$) engine, has a power of $60\,\text{kW}$. The static friction coefficient between wheels and road is $k=0.6$. How long does it take to reach the speed of ...
0
votes
2answers
195 views
What is the force of friction between two bodies given their masses and a force pulling them as a unit accross a surface?
Where a force of 200N pulls two blocks together(as one system) across a horizontal table top(ยต=0.800)
$m_A$ = 5.00kg, $m_B$ = 10.0kg
Find the acceleration of the system.
Find f$_k$ between B and A
...
5
votes
2answers
152 views
Boy and box on ice
I have a troubles. Can you help me?
I have a task, called "slippery activity".
Boy (he has $m=45kg$) Stands at ice and tries to move a big box ($M=90kg$) with a string (rope). Boy's Slip ratio is ...
2
votes
1answer
125 views
Understanding Work and the conservation of energy
We have a car with a mass of $780 kg$ with travels with a speed of $50 km/h$. The car brakes and after $4,2m$ is stops completely. Warmth is created. Calculate the friction.
I solved this easily, by ...
0
votes
0answers
74 views
Describing the movement of the object in a particular situation in Lagrangian way
Suppose there is a object M, (sliding motion) moving by the initial speed $v$ and the initial location $x_0$. Otherwise noted, friction is assumed to be nonexistent. It then meets a circular mold ...
3
votes
2answers
185 views
Does air resistance ever slow a particle down to zero velocity?
If a particle moves in a place with air resistance (but no other forces), will it ever reach a zero velocity in finite time? The air resistance is proportional to some power of velocity - $v^\alpha$, ...
1
vote
3answers
434 views
Is it possible to find out the distance traveled by a car if the force applied on it is given?
Say you have car which produces $F$ amount of force which is transferred to the wheels directly.
Now assuming that there is air friction which is causing a retarding force proportional to the ...
1
vote
1answer
278 views
Overcoming Friction
Let's say a box is moved by attaching a rope to it and pulling with an applied force at a certain angle. Now, let's say that this is being done on an inclined ramp. How would I find the acceleration?
...
1
vote
1answer
233 views
Kinematics - Find theta with Coefficient of Friction?
I recently found a problem that looked like this:
A box sits on a horizontal wooden ramp. The coefficient of static friction between the box and the ramp is ...
0
votes
1answer
2k views
How to calculate work done by variable kinetic friction force?
A heavy chain with a mass per unit length $\rho$ is pulled by the constant force $F$ along a horizontal surface consisting of a smooth section and a rough section. The chain is initially at rest on ...
2
votes
3answers
960 views
How do I find work done by friction over a curve represented by a polynomial?
I am facing a problem in Physics.
Problem: What will be the work done by the frictional force over a polynomial curve if a body is sliding on this polynomial($a+bx+cx^2+dx^3+\ldots$) curve from rest ...
0
votes
0answers
542 views
Capstan equation [closed]
This problem is from An Introduction To Mechanics book, chapter 2, problem #24.
A device called a capstan is used aboard ships in order to control
a rope which is under great tension. The rope is ...
1
vote
1answer
164 views
What controls whether a ball will skid or roll?
A billard ball is struck with a cue. The line of action of the applied impulse is horizontal and passes through the center of the ball. The initial velocity $v_0$ of the ball, its radius $R$, its mass ...
0
votes
0answers
107 views
A problem on mechanical energy and friction
I'm studying for a mid-term, and I'm trying to solve some mock-papers. The following are two problems which I have solved, but I'm missing a part:
$(1)$ A body of mass $ m_1= 8 \rm kg$ passes ...
0
votes
1answer
122 views
Does friction act in the same way in different directions?
A physics textbook is launched up a rough incline with a kinetic energy of $X$ joules. When the book comes momentarily to rest near the top of the incline, it has only gained ($X-20$) joules of ...
0
votes
2answers
340 views
Finding Distance an Object Travels Up an Incline After Launch
I've been doing a review for an introductory physics course final. I have a question on one problem though. Here is the problem:
A mass (M=2kg) is placed in front of a spring with k=900N/m,
...
0
votes
0answers
109 views
Load vs Leverage vs Friction on a floating pivot [closed]
If I had a standard 'cherry-picker' type of crane (lifting device), 7' high, with a 7' boom, suspending 1000# at its end,its vertical support mounted atop a 6" diameter ball-type pivot: how much force ...
0
votes
1answer
80 views
Is this a correct addition to a pipe friction loss calculation?
I've been using this online calculator to work out the difference in pressure and flow between two ends of a pipe:
Pipe Friction Calculation for Fluid Flow in a Pipe
So far most of it makes sense, ...
0
votes
2answers
379 views
Ropes and Pulleys - Really unintuitive answer
I usually don't want to do this, but please go to this link, the solution is too big to post it here
http://engineering.union.edu/~curreyj/MER-201_files/Exam2_2_26_09_Solution.pdf
And go to page 5 ...
-1
votes
1answer
122 views
Find largest angle
The two homogeneous bars AB and BC are connected with a pin at B and
placed between rough vertical walls. If the coefficient of static friction between
each bar and the wall is 0.4, determine the ...
0
votes
2answers
691 views
static friction problem without mass
I am having trouble with a physics problem. The problem is as follows:
A car is traveling at 54.0 mi/h on a horizontal highway.
A) If the coefficient of static friction between road and tires on a ...
0
votes
0answers
304 views
Newton's 2nd law (f=ma) to derive an expression for the resultant force on the block [closed]
A block. initially at rest , slides down a slope as shown. the frictional force is calculated to be 160N and the air resistance is 0.5v, where v is the velocity of the block.
if the weight acting down ...
0
votes
1answer
141 views
M1 vs M2 on a frictionless surface
I was wondering, if I had a frictionless surface and I had an M1 that was 100kg and an M2 that was 1kg and I pushed each separately with an equal force F would they move at the same speed or am I ...
1
vote
1answer
1k views
Two problems with free body diagrams. Contradictions (solutions are provided)
This problem is similar, but also different question from my previous question. They are both unfortunately long.
Problem/Solution #1
!
!
Quick Concept Check
a) Could someone briefly explain to me ...
-1
votes
1answer
377 views
please help with a friction problem! [closed]
My Problem is the #120 in this page (someone please edit and rotate this image, bcause i don't know how to rotate it):
http://i.stack.imgur.com/fBn9C.png
It is a regent practice question,any help ...
0
votes
0answers
349 views
Reynolds Number and relation to Moody Diagram for a Small Pipe
I am having the following problem on a lab write up:
Calculate the approximate distance downstream of the inlet that
corresponds to the hydrodynamic entry length for Reynolds numbers of
3,000 ...
3
votes
3answers
269 views
Braking distances on a rainy road
I am curious to find the braking distance for a car on a road.
In attempting to find this out, I found that the braking distance for a car (on a flat road) is
$$
d = \frac{v^2}{2\mu g}
$$
where
...
