A Model of FrictionThese ideas can be summarized in a model of friction:TABLE 6.1 Coefficients of frictionStatic Kinetic RollingStatic: f, < (µzn, direction as necessary to prevent motion)Kinetic: FRolling: ,Materials= (uk n, direction opposite the motion)= (µ,n, direction opposite the motion)(6.15)Rubber onconcrete1.000.800.02Steel on steel(dry)0.800.600.002Here “motion" means “motion relative to the surface." The maximum value of staticSteel on steelfriction f. max = µ̟n occurs at the point where the object slips and begins to move.(lubricated)0.100.05NOTE > Equations 6.15 are a “model" of friction, not a “law" of friction. Theseequations-a simplification of reality-provide a reasonably accurate, but not per-fect, description of how friction forces act. They are not a “law of nature" on a levelWood on wood0.500.20Wood on snow0.120.06Ice on ice0.100.03with Newton's laws. « The skiing duo of Brian (81 kg ) and Ashley (54 kg ) is always a crowd pleaser. In oneroutine, Brian, wearing wood skis, starts at the top of a 290-m-long, 20° slope. Ashleywaits for him halfway down. As he skis past, she leaps into his arms and he carriesher the rest of the way down. Hint. Use coefficient of kinetic friction from Table 6.1 inthe textbook.Part AWhat is their speed at the bottom of the slope?Express your answer to two significant figures and include the appropriate units.?v =ValueUnitsSubmitRequest Answer

Given, Mass of Brian, mB = 81 kg Mass of ashley, mA = 54 kg Length L=290m Distance d=145m Angle, θ=20°Coefficient of friction, μk=0.06 [from table 6.1 (wood on snow)]As net force, Fnet=ma =mgsin(θ)-μkmg(cosθ)⇒a=gsinθ-μkgcosθ =10(sin20°-0.06cos20°) =2.85 ms2 This is the acceleration found. From using equation of motions, Velocity becomes, v2=u2+2as⇒v=02+2(2.85)(145)⇒v=28.74 ms Using conservation of momentum, Initial momentum equals final momentum, mBv=(mA+mB)vf⇒81(28.74)=(81+54)vf⇒vf=17.24 ms Using same equation of motion again, we get, v2=u2+2as⇒v=(17.24)2+2(2.85)(145) [As vf=u]⇒v=297.21+826.5⇒v=33.52 msHence, their speed at the bottom of the plane is 33.52 m/s

Science

Physics

The skiing duo of Brian (81 kg ) and Ashley (54 kg ) is always a crowd pleaser. In one routine, Brian, wearing wood skis, starts at the top of a 290-m-long, 20° slope. Ashley waits for him halfway down. As he skis past, she leaps into his arms and he carries her the rest of the way down. Hint Use coefficient of kinetic friction from Table 6.1 in the textbook. Part A What is their speed at the bottom of the slope? Express your answer to two significant figures and include the appropriate units.

The skiing duo of Brian (81 kg ) and Ashley (54 kg ) is always a crowd pleaser. In one routine, Brian, wearing wood skis, starts at the top of a 290-m-long, 20° slope. Ashley waits for him halfway down. As he skis past, she leaps into his arms and he carries her the rest of the way down. Hint Use coefficient of kinetic friction from Table 6.1 in the textbook. Part A What is their speed at the bottom of the slope? Express your answer to two significant figures and include the appropriate units.

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

See similar textbooks

Similar questions

A 2.0 kg particle moving along the x-axis experiences the force shown in (Figure 1). The particle's velocity is 3.0 m/s at x=0 m. At what point on the x-axis does the particle have a turning point?
A rifle with a barrel length of 60 cm fires a 15 g bullet with a horizontal speed of 350 m/s. The bullet strikes a block of wood and penetrates to a depth of 13 cm. You may need to review (Page). For general problem-solving tips and strategies for this topic, you may want to view a Video Tutor Solution of Ready for takeoff. Part A What resistive force (assumed to be constant) does the wood exert on the bullet? Express your answer with the appropriate units. Part B. How long does it take the bullet to come to rest after entering the wood? Express your answer with the appropriate units.
When serving a tennis ball, the player hits it when its velocity is zero (at the highest point of a vertical toss). The racket exerts a force of 530 N on the ball for 5.00 ms, giving it a final velocity of 44.0 m/s. Using these data, find the mass of the ball. g Additional Materials I Reading
A pile driver lifts a 250 kgkg weight and then lets it fall onto the end of a steel pipe that needs to be driven into the ground. A fall of 1.5 mm before striking the pipe drives the pipe in 40 cmcm. Part A What is the average force that the weight exerts on the pipe? (Hint: Let the weight be the system)
An 8.00 kg crate sits on an inclined plane that is inclined at 33.0 above the horizontal. The coefficient of kinetic friction between the crate and the surface of the plane is 0.300. A constant horizontal force F = 28.0 N is applied to the crate (Figure 1), and the crate moves down the plane. Part A If the crate is initially at rest, find its speed 2.00s after the force is applied? Express your answer with the appropriate units. HA Value Units Figure 1 of 1> Submit Request Answer Provide Feedback F 33.0°
A physics professor is pushed up a ramp inclined upward at an angle 30.0° above the horizontal as he sits in his desk chair that slides on frictionless rollers. Part A The combined mass of the professor and chair is 86.0 kg. He is pushed a distance 2.10 m along the incline by a group of students who together exert a constant horizontal force of 610N. The professor's speed at the bottom of the ramp is 1.85 m/s Use the work-energy theorem to find his speed at the top of the ramp. Express your answer in meters per second. V ΑΣφ ? V = m/s 國
It is friction that provides the force for a car to accelerate, so for high-performance cars the factor that limits acceleration isn't the engine; it's the tires. For the steps and strategies involved in solving a similar problem, you may view a Video Tutor Solution. Part A For typical rubber-on-concrete friction, what is the shortest time in which a car could accelerate from 0 to 50 mph? Suppose that us = 1.00 and k = 0.80. Express your answer with the appropriate units. 20 Submit μA Δt = |11.404 S Previous Answers Request Answer ? Review | Constants | Periodic Table X Incorrect; Try Again; 4 attempts remaining 7:54 PM
A 2.2×104 kg rocket has a rocket motor that generates 2.7×105 N of thrust. Part A What is the rocket's initial upward acceleration? Express your answer with the appropriate units. Part B At an altitude of 5000 m the rocket's acceleration has increased to 7.5 m/s². What mass of fuel has it burned? Express your answer with the appropriate units.
n the figure to the right, the hanging mass m) is 2.50kg. What would be the required mass on the table (M) for the system to move with an acceleration of a=7.25m/s²? part of your solution, you are required to fill out the following: As
A small block with mass 0.0450 kg slides in a vertical circle of radius 0.0710 m on the inside of a circular track. There is no friction between the track and the block. At the bottom of the block's path, the normal force the track exerts on the block has magnitude 3.70 N Part A What is the magnitude of the normal force that the track exerts on the block when it is at the top of its path?
A medium-sized jet has a 3.8-m-diameter fuselage and a loaded mass of 85,000 kg. The drag on an airplane is primarily due to the cylindrical fuselage, and aerodynamic shaping gives it a drag coefficient of 0.37. Part A How much thrust must the jet's engines provide to cruise at 240 m/s at an altitude where the air density is 1.9 kg/m³? Express your answer with the appropriate units.
Ⓒ Macmillan Learning A block of mass m = 6.23 kg is attached to a spring that is resting on a horizontal, frictionless table. The block is pushed into the spring, compressing it by 5.00 m, and is then released from rest. The spring begins to push the block back toward the equilibrium position at x = 0 m. The graph shows the component of the force (in newtons) exerted by the spring on the block versus the position of the block (in meters) relative to equilibrium. Use the graph to answer the questions. How much work W is done by the spring in pushing the block from its initial position at x = -5.00 m to x = 2.20 m? W = V = -59.04 Incorrect What is the speed of the block when t reaches x 2.20 m? 2.41 Incorrect Umax = What is the maximum speed max of the block? 3.63 J Incorrect m/s m/s 6 5. 4. 3. 2 ↓ L₁ -3. -4. -5. -6. F (N) x(m) $