Static friction Definition and 507 Threads

Homework Statement Suppose I have a brick that's sitting at the edge of a disc that is rotating clockwise with uniform circular motion. I what direction(s) are the forces of static friction acting? Homework Equations a = v^2/r The Attempt at a Solution I know that a...

Homework Statement If a curve with a radius of 85m is properly banked for a car traveling 65 km/h what must the coefficiant of static friction be for a car not to skid when traveling at 95km/h Homework Equations For this question i tried using a few equations such as centripical force...

Problem: A top-loading washing machine has a spin cycle that rotates at 8.5 cycles per second. The spinning drub that holds the clothes has a radius of 35 cm. What is the linear speed of the clothes? ω = (8.5 cycles/s) / (2pi rad) = 53.4 rad/s v = ωr = (53.4 rad/s) * (0.35 m ) = 19 m/s...

Homework Statement If a curve with a radius of 87.5 m is perfectly banked for a car traveling 71.8 km/hr, what must be the coefficient of static friction for a car not to skid when traveling at 93.8 km/hr? Homework Equations tan \theta = v^{2} / r*g The Attempt at a Solution I...

Homework Statement If a curve with a radius of 77.0 m is perfectly banked for a car traveling 65.8 km/hr, what must be the coefficient of static friction for a car not to skid when traveling at 91.2 km/hr? Homework Equations \mus = v^2/(g*r) The Attempt at a Solution 1 Incorrect...

Homework Statement To test the performance of its tires, a car travels along a perfectly flat (no banking) circular track of radius 412 m. The car increases its speed at uniform rate of, at= 4.14m/s^2, until the tires start to skid. If the tires start to skid when the car reaches a speed of...

Homework Statement A boy has stacked two blocks on the floor so that a 5.0 kg block is on top of a 2.0 kg block. 1. If the coefficient of static friction between the two blocks is 0.40, and the coefficient of static friction between the bottom block and the floor is 0.22, with what force...

Homework Statement A woman attempts to push a box of books that has mass 36.5 kg up a ramp inclined at an angle 27.5 degrees above the horizontal. The coefficients of friction between the ramp and the box are mu_s and mu_k. The force F applied by the woman is horizontal. Assume that mu_s is...

Homework Statement A block of mass 1.2 kg rests on top of another block of mass 1.8 kg, which rests on a frictionless surface. The coefficient of static friction between the blocks is mu_s = 0.3. (a) What is the maximum horizontal force that can be applied to the upper block so that the...

Homework Statement To test the performance of its tires, a car travels along a perfectly flat (no banking) circular track of radius 331 m. The car increases its speed at uniform rate of at ≡ d|v|dt = 3.68 m/s^2 until the tires start to skid. If the tires start to skid when the car reaches a...

Homework Statement You are in a car accelerating the car at 15 m/s^2 without spinning tires out. determine the minimum coeff of static friction between the tires and the road to make this possible Homework Equations The Attempt at a Solution

how can i find static friction...if i don't have a spring balance of any material to find it...pls help!we need this to our defense...thank you...:shy:

Homework Statement 2 blocks are connected with wire each on its own angle area. Body 1 (B1) has weight 900N, angle 30, µ = 0,35 B2 wight = 1100N, angle 45 and µ=0.30 There is no friction on at the T ( picture ) How big F has to be to pull block1 down following shown path? Homework...

Homework Statement A 2000kg car makes a left run of radius 6.5 m. If this turn is made in 2 seconds, what isthe force of static friction of the car during the turn? Homework Equations a = v^2/r, F = (m*v^2)/r ; d = v*t; The Attempt at a Solution d/t = v = 3.25 m/s Fc =...

A 5kg block is placed on top of a 15kg block that rests on a frictionless table. The surface between the top and bottom blocks is roughened so that there is no slipping between the blocks. A 40N horizontal force is applied to the top block. What is the minimum coefficient of static friction...

Homework Statement A block of mass m1 = 2.0 kg is stacked on top of a block of mass m2 = 3.0 kg which is resting on top of a table Both blocks and the table are made of the same material; so the coefficients of friction between all surfaces are the same They are (attempt at a mew) ms = .60...

Homework Statement 9. A 2000 kg car is racing around a banked circular path whose radius of curvature is 50.0m. The coefficient of static friction between the car and the road is 0.100. What is the maximum possible speed for the car to remain on the road if the angle of the curve is 15°...

Homework Statement A block of mass m lies on a rough surface, inclined at angle theta to the horizontal. It is attached to a spring of force constant; the other end of the spring is fixed to a point on the table below the inclined block. The co-eff of static friction is mu-s and kinetic...

Homework Statement A spool rests on a horizontal surface on which it rolls without slipping. The middle section of the spool has a radius r and is very light compared with the ends of the cylinder which have radius R and together have mass M. A string is wrapped around the middle section so...

Okay, I have been coming across a lot of problems that share something in common; They all ask what is the minimum amount of force required to move the object. Alright, so I've been looking all over the internet and have been finding varying answers from If the Pushing force (P) equals Fsmax...

Homework Statement In a circular flat track of radius 50m, what is the maximum speed car can go without sliding? Assume the coefficient of static friction between the car tire and the road is 0.4. Homework Equations Unsure of what equations to use. The Attempt at a Solution Unsure...

Hello all. I'm having issues trying to figure out the following problem. A boy with a mass of 52 kg and on a 56-degree slope is hanging on to a cord with a breaking strength of 152 Newtons. What must be the coefficient of static friction between the boy and the surface?

Homework Statement A small metal cylinder of mass m=0.20 kg sits on a rotating turntable. The coefficient of static friction between the metal cylinder and the turntable is us=.08. The cylinder is located 0.15m from the center of the turntable. Find the maximum speed that the cylinder can...

Homework Statement A 25 kg chair intially at rest on a horizontal floor requires 365 N horizontal force to set it in motion. Once the chair is in motion, a 327 N horizontal force keeps it moving at a constant velocity. A: Find the coefficient of Static Friction between the chair and the...

Homework Statement http://img124.imageshack.us/img124/9997/problem3.jpg Homework Equations f=mgcos theta The Attempt at a Solution I am thinking the answer is f = mgcos theta because gravity only acts on y-component but the answer is f=mgsin theta . Can anyone explain?

Homework Statement a mass m is supported as shown in the figure by ideal strings connected to a rigid wall and to tal mass 3m sitting on a horizontal surface. what is the minimum coefficient of static friction between the larger mass and the surface that permits the system to remain in...

Not exactly a homework problem, but I'm trying to make sure I understand how the coefficient of static friction works. Given an object on an inclined plane and a question which asks for the minimum angle at which the object will begin to slide, I know that the formula to use is: mg...

Homework Statement The coefficient of static friction is 0.60 between the two blocks in figure. The coefficient of kinetic friction between the lower block and the floor is 0.20. Force causes both blocks to cross a distance of 5.0 m, starting from rest. What is the least amount of time in...

1. What is the actual static frictional force that acts on the block if an external force of 25.0 N acts horizontally on the block? ________N The mass of the block is 25.0kg. Assume g=9.80m/s^2 Homework Equations I am using: static frictional force=(coefficient of static...

Homework Statement A block of mass m is resting on a horizontal surface whose coefficient of static friction is μs. http://bcs.whfreeman.com/WebPub/Physics/tiplerphysics6e_bridge/question_bank_images/fig5-65.png?2439 Which of the following statements (if any) are true? A. If you...

Homework Statement http://img3.imageshack.us/img3/6618/5n6.jpg Image there. Homework Equations Well this is actually where the problem occurs. You make your own equations. The Attempt at a Solution It's the friction that is really messing me up. I'm just so confused, I'm going to...

Homework Statement What is the maximum speed with which a 1200 rubber-tired car can take around a banked curve with radius of 80.0 meters an angle of 19.0 degrees? (static friction coefficient is 1.0) Homework Equations Fs=mu*F(normal) F(netxdirection)/m=acceleration...

OK, so in my physics class we are doing friction. And the book states that static friction usually larger then kinetic. Then he posed a question to whether or not there might be some crazy scenario where the kinetic friction is larger than the static friction? Personally, I cannot think of...

Homework Statement http://img182.imageshack.us/img182/8174/p560.gif An aluminum block, m1 = 5.00 kg, and a copper block, m2 = 15.36 kg, are connected by a light string over a frictionless pulley. They sit on a steel surface as shown in the figure below, where θ = 30.0°. (See the table...

One of our new labs states that the coefficient of static friction is USUALLY higher than the coefficient of kenitic friction. Is this true? If so, for what types of materials is the coefficient of static friction less than the coefficient of kenitic friction?

HI guys, i was wondering what is the difference between inertial and static friction? If a car is on a frictionless ground, does it have static friction and the inertial is the same even if it is on a rough surface right?

Homework Statement You try to push a crate of weight M with a force F on a horizontal floor. The coefficient of static friction is μ and you exert the force F under an angle θ below the horizontal. a) Determine the minimum value of F that will move the crate b) Assume you have not...

State the Problem End A of a slender, uniform rod of weight w and length L bears on a horizontal surface ash shown, while end B is supported by a cord BC of length L. Knowing that the coefficient of static friction is 0.40, determine (a) the value of theta for which motion is impending, (b)...

[b]1. A box sits on a horizontal wooden board. The coefficient of static friction between the box and the board is 0.22. You grab one end of the board and lift it up, keeping the other end of the board on the ground. What is the angle between the board and the horizontal direction when the box...

Homework Statement The 70-kg climber is supported in the "chimney" by the friction forces exerted on his shoes and back. The static coefficients of friction between his shoes and the wall, and between his back and the wall, are 0.80 and 0.60, respectively. What is the minimum normal force he...

Homework Statement A bug crawls outward from the center of a compact disc spinning at 190 revolutions per minute. The coefficient of static friction between the bug's sticky feet and the disc surface is 1.4. How far does the bug get from the center before slipping? Homework Equations...

Ok so this is only my second thread (and post) on this site. My question is that if you push something that doesn't deform very much (like wood) or move because of static friction how is energy conserved. Only going to be in 8th grade so try to keep it simple please. :smile: <-- just...

Homework Statement okay, I know it says be descriptive and all, but I'll present a watered down problem with some insignificant data already calculated by me. my problem is to understand the logic behind the solution, I know the solution, I simply think my textbook is... false. here goes...

I am having a lot of problems with the tension/force questions on my homework. Here is the last question I don't understand in my homework set: The drawing shows a circus clown who weighs 860 N. The coefficient of static friction between the clown's feet and the ground is 0.41. He pulls...

Homework Statement Suppose the rod in the figure has mass m= 0.44 kg and length 26 cm and the current through it is I= 40 A. Part A: If the coefficient of static friction is mus= 0.45, determine the minimum magnetic field B (not necessarily vertical) that will just cause the rod to...

Homework Statement There's a ride called the Cajun Cliffhanger. it's a rotating drum that rotates and makes you stick to the walls. here's are the infomation The diameter is 5.3m the speed is 4.2 seconds per rotation at final speed it takes 10.1 seconds to reach the final speed You have...

Homework Statement A uniform 6.0m long ladder of mass 17.0 kg leans against a smooth wall (so the force F_w exerted by the wall, , is perpendicular to the wall). The ladder makes an angle of 22.0 with the vertical wall, and the ground is rough.Determine the coefficient of static friction at...

Homework Statement The coefficient of static friction between your hand and a pie is 0.70. if you want to put a cream pie pie in someone's face, what is the minimum acceleration needed to keep it from sliding down your vertical hand? The Attempt at a Solution Im not sure how to go about this...

If an object slides down a slope at a constant speed is the coefficient of static friction the same as the coefficient of dynamic friction? If yes, is this true in every situation?

Homework Statement If a curve with a radius of 90 m is properly banked for a car traveling 68 \frac{km}{h}, what must be the coefficient of static friction for a car not to skid when traveling at 98 \frac{km}{h}?Homework Equations I know I need \Sigma \vec{F} = m \vec{a}f_s <= \mu_s N and...