Kinetic friction Definition and 509 Threads

Homework Statement This is what I was given: A block is placed on a rough wooden plane it is found that when the plane is tilted 30° to the horizontal, the block will slide down at a constant speed. Homework Equations I'm not sure which equations to use other than sinΘmg but I'm not getting the...

A flight attendant pulls her 70.0 N flight bag a distance of 269 m along a level airport floor at a constant speed. The force she exerts is 32.0 N at an angle of 52.0° above the horizontal. (a) Find the work she does on the flight bag. _5299_J (b) Find the work done by the force of friction...

Homework Statement A box of textbooks of mass 24.6 kg rests on a loading ramp that makes an angle theta with the horizontal. The coefficient of kinetic friction is 0.23 and the coefficient of static friction is 0.35. A. As the angle theta is increased, find the minimum angle at which the...

Homework Statement (a) suppose the coefficient of μκ between m1 and the plane in Fig 4-57 is 0.15, and that m1=m2=2.7 kg. As m2 moves down, determine the magnitude of the acceleration of m1 and m2, given θ = 25°. (b) What smallest value of kinetic friction will keep this system from...

Can the kinetic friction be in the direction of acceleration? I am thinking of the example of a box on a flatbed truck accelerating to the right from rest. The box accelerates to the left due to the inertial force as seen by an observer on the truck where the kinetic friction is opposite to the...

Homework Statement A 12g coin slides upward on a surface that is inclined at an angle of 14degrees above the horizontal. The coefficient of kinetic friction between the coin and the surface is 0.25; the coefficient of static friction is 0.40. Find the magnitude of the force of friction when...

i feel really dumb but i have this physics homework question i can't get. a 20kg sled is being pulled across a horizontal surface at constant velocity. the pulling force has a magnitude of 80N at a 30 degree angle above the horizontal. find the coefficient of kinetic friction.

Homework Statement A block(7 kg) is released from rest on an inclined plane of 23 degrees and moves 2.8 m during the next 4.7 s. The acceleration of gravity is 9.8 m/s^2. What is the magnitude of the acceleration of the block? What is the coefficient of kinetic friction for the incline...

I have this homework question: A sled is pulled with a horizontal force of 15 N along a level trail, and the acceleration is found to be 0.40 m/s2. An extra mass m = 4.3 kg is placed on the sled. If the same force is just barely able to keep the sled moving, what is the coefficient of kinetic...

Homework Statement At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails, weigh 10kg (box 1) and 20kg (box 2), respectively and are both the same...

Homework Statement A pig is sliding down a ramp that has an angle of 35 degrees from the horizontal plane. If the friction coefficient was 0 the ride would only take half the time. What is the kinetic friction coefficient between pig and ramp?Homework Equations Fnet = ma v² = u² + 2as a =...

Homework Statement A grindstone in the shape of a solid disk with diameter .52m and mass 50 kg is rotating at 850 rev/min. You press an ax against the rim with a normal force of 160 N and the grindstone comes to a rest in 7.5 seconds. Find the coefficient of kinetic friction of the ax on the...

Anybody know where I can find data on normal street-tire friction coefficients on dry asphalt? I'd like both the static, and the kinetic coefficients. If not, can somebody give me a range of reasonable values? While I'm at it... What about racing slicks on asphalt? I found one source...

Hi, So I've read that kinetic friction does not depend upon velocity, but that air resistance does depend upon velocity. I hope those two statements are correct from the get go. I can see why the force of kinetic friction does not depend upon speed using a simple thought experiment. You...

Hi, The problem attached is a kinetic problem. problem # 50. This is from belts friction that this question is from. All my other problems have dealt with static, and now with kinetic, I am stuck on what to do. There is no impending motion that I know. Would I take the rope with the 45...

Homework Statement A block of mass 15.0 kg sits on a plane that is inclined at a 37.0° angle to the horizontal. A 227 N force, pointing up the plane, is applied to the block. The coefficient of kinetic friction is 0.500. What is the speed of the block after 2.00 s? Homework Equations m =...

Homework Statement A child goes down a playground slide with an acceleration of 1.32 {m/s^2}. Find the coefficient of kinetic friction between the child and the slide if the slide is inclined at an angle of 35.0 deg below the horizontal. Homework Equations Fnet=ma Fg=mg Ff=uFn I...

Homework Statement Sam, whose mass is 71.0 kg , takes off down a 51.0 m high, 11.0 degree slope on his jet-powered skis. The skis have a thrust of 210 N . Sam's speed at the bottom is 41.0 m/s . Homework Equations I'm not sure which equation(s) to use. Net Force= ma and some kinematic...

1. A block is projected up an incline making an angle theta with the horizontal. It returns to its initial position with half its initial speed. Show that the coefficient of kinetic friction is μk = (3/5)tan(theta) (For a 'properly formatted' version of the question, see number 3 on the...

A skier is traveling at a constant speed of 4 m/s on a ski slope. The kinetic coefficient of frictionbetween her skis and the slope is 0.2. Find the angle of the slope. attempt: sin feda = f/w but i have no weight f=mgsinfeda and N=mg cos feda all of this ends up being mu=tan feda but...

Homework Statement A car is moving with a velocity of 20m/s when the brakes are applied and the wheels lock (stop spinning), The car then slides to a stop in 40m. FInd the coefficient of kinitic friction between the tires and the road. Homework Equations F=ma Ffriction=coefficient...

Homework Statement The lower block in the figure is pulled on by a rope with a tension force of 20 N. The coefficient of kinetic friction between the lower block and the surface is 0.30. The coefficient of kinetic friction between the lower block and the upper block is also 0.30. Find the...

1. The problem statement A 10 kg block is released from point A on a track ABCD. The track is frictionless except for the portion BC, of length 6 m. The block travels down the track and hits a spring of force constant k = 2250 N/m and compresses it a distance of 0.3 m from its equilibrium...

Homework Statement A box is held on a rough plank inclined at an angle of 60° to the horizontal. The box is released from rest and slides down the plank with a constant acceleration of 5 m/s2. Calculate the coefficient of kinetic friction between the box and the plank. Homework...

Homework Statement mA=5kg , mB =10kg , coeff of friction is same for static and kinetic friction = 0.15 g=10ms-2 2 blocks a , b are in contact with each other resting against a rigid wall on a horizontal surface. There is fricition acting between the blocks and the surface . A force of...

Homework Statement The task was to find the kinetic friction of a puck that is shot from an elastic string. The puck was sliding on a cardboard plane. To do this, I was advised find the work done on the puck, and have therefore collected the following data: Distance Traveled Force the...

Homework Statement It is known that 1500 revolutions are required for the 6000-lb flywheel to coast to rest from an angular velocity of 3000 rpm. Knowing that the radius of gyration of the flywheel is 36 in., determine the average magnitude of the couple due to kinetic friction in the...

Homework Statement A 25 kg box slides down a 26 degree ramp with an acceleration of 1.32 m/s2. The acceleration of gravity is 9.81 m/s2 Find the coefficient of kinetic friction between the box and the ramp. Homework Equations mass = m = 25 kg angle = (theta) = 26 degrees acceleration =...

Part A: A block of mass M resting on a 18.8° slope is shown. The block has coefficients of friction μs=0.620 and μk=0.314 with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass 2.97 kg. What is the minimum mass M1 that will stick...

Homework Statement 2 masses, are attached to a spring as follows: (trying my best to illustrate) [M1]----[M2] (the ---- represents a spring between 2 masses) M1 = 0.25kg M2 = 0.5kg The spring is compressed 0.08m, and then the 2 masses are released simultaneously. If the...

Homework Statement A boy pushes a light snow shovel at a uniform velo across a sidewalk. If the handle of the shovel is inclined at 55deg to a horizontal and he pushes along the handle with a force of 100N. What is the coefficient of kinetic friction. Homework Equations Ff=...

Homework Statement This is for a lab, I need help finding the coefficient of kinetic friction since when I solve I get a negative answer. In the lab we have a block of wood that has a downward weight of 2.12 N. It is on a ramp set at 20 degrees and we pulled it UP THE RAMP. Using the laptop...

Homework Statement Find the force(F) needed to move a 50kg box up a ramp angled at 40 degrees with an acceleration of 1m/(s^2) while pulling at an angle of15 degrees above parallel to the ramp. the ramp has a frictional constant of .1 a=1m/(s^2) m=50kg angle of ramp=40 degrees angle...

Homework Statement A baggage handler drops your 7.00 kg suitcase onto a conveyor belt running at 2.30 m/s. The materials are such that µS= 0.410 and µK= 0.250. Homework Equations How far is your suitcase dragged before it is riding smoothly on the belt? The Attempt at a Solution...

Homework Statement A force of 25N accelerates a 9.0 kg wagon at 1.5 m/s2. Calculate the coefficient of the kinetic friction. Homework Equations Ff=MkFN ^^Or at least I think so. The Attempt at a Solution What does the coefficient of the kinetic friction mean first off? I...

Homework Statement A 22kg box is being pulled across a flat surface by a rope at a 25 degree angle with the floor. What is the kinetic friction coefficient? Homework Equations (Fnet)y= -mg + Tsin() + n(normal force) (Fnet)x= Tcos() + kf The Attempt at a Solution I cannot...

Homework Statement I have a lab on friction I did in class, I have missed couple of days and and its due today, what i need to know is how can i calculate the friction of the object if I have the following given , the time it took for the object to come down the raamp, the displacement , the...

1. I have a lab on friction I did in class, I have missed couple of days and and its due today, what i need to know is how can i calculate the friction of the object if I have the following given , the time it took for the object to come down the raamp, the displacement , the height of the...

Homework Statement you absolutely need to see the picture for this one, it has the question printed next to it http://s861.photobucket.com/albums/ab174/alkaline262/?action=view&current=ch6prob19-1.jpg Homework Equations well, i was thinking about using master conservation of energy theorem...

A crate of oranges weighing 176 N rests on a flatbed truck 2.0 m from the back of the truck. The coefficients of friction between the crate and the bed are μs = 0.30 and μk = 0.20. The truck drives on a straight, level highway at a constant 6.3 m/s. a. What is the force of friction acting on...

Homework Statement (1) Firstly, the block as it rest at incline of 10 degrees and mass is added on the other side of pulley to overcome static friction (0.0063kg). The block weighs 0.8kg. Calculate the tension. (2) The block is at same angle and mass but this time the block was lightly pushed...

max \mus is always larger than \muk. i think it's proven experimentally, but why exactly is this so?

How to find the degree of inclination if there is only coefficient of kinetic of friction is given & a constant velocity? the coefficient of kinetic friction between a wooden box and an inclined plane is 0.30. At what angle will the box slide with a constant velocity once set in motion?

Hello everyone, In electrophoresis the least dense one moved less (other factors been the same for every particle). I'm assuming this is due to higher volume and more resistance but, doesn't electrophoresis measure kinetic friction, so the one with lowest density should move further. What...

Homework Statement Assume that the driver begins to brake the car when the distance to the wall is d=107m, and take the car's mass as m-1400kg, its initial speed as vo= 35m/s and the static coefficient to be .50. Assume that the car's weight is distributed evenly on the four wheels, even...

Homework Statement What is the network done on the car during the time interval? Mass = 75,000kg Vi = 0 vf = 111.11m/s^2 t = 2.5s ∆x = 138.8875m Homework Equations W= F∆X ∆KE = (1/2)(m)(v)^2 W = ∆KE The Attempt at a Solution ∆KE = 1/2(75000kg)(111.11m/s)^2 ∆KE =...

Two blocks are connected by a cord on a horizontal surface. A force F pulls on the 15-kg block as shown in the figure. Find the tension in the cord connecting the two blocks to each other if the coefficient of kinetic friction between each block and the ground is 0.2. ----------T=?------- 25KG...

coefficient of kinetic friction, URGENT need today The system shown in the figure below has an acceleration of magnitude 0.51 m/s2, where m1 = 4.30 kg and m2 = 6.00 kg. Assume that the coefficient of kinetic friction between block and incline is the same for both inclines. Link to figure...

Homework Statement a force of 15 N {south} moves a case weighing 40 N { down} across a level surface at constant velocity. what is the coefficient of kinetic friction for the cae on the counter Homework Equations Force of friction = the coefficient of friction(μ) x normal forceThe Attempt at...

Homework Statement A man pushes a chair that weighs 60N with a force of 25N. The chair has a final speed of 4.0m/s. and a kinetic friction of .27. What is the acceleration? Homework Equations i have no idea where to start, i tired this formula that had me find distance but the...