Concept explainers
Tilting trains, such as the Acela Express that serves the Northeast Corridor in the Northeast United States, are designed to travel safely at high speeds on curved sections of track which were built for slower, conventional trains. As it enters a curve, each car is tilted by hydraulic actuators mounted on its trucks. The tilting feature of the cars also increases passenger comfort by eliminating or greatly reducing the side force Fs (parallel to the floor of the car) to which passengers feel subjected. For a train traveling at 100 mi/h on a curved section of track banked through an angle θ = 6° and with a rated speed of 60 mi/h, determine (a) the magnitude of the side force felt by a passenger of weight W in a standard car with no tilt (ϕ = 0), (b) the required angle of tilt ϕ if the passenger is to feel no side force. (See Sample Prob. 12.7 for the definition of rated speed.)
Fig. P12.53 and P12.54
Want to see the full answer?
Check out a sample textbook solutionChapter 12 Solutions
VECTOR MECH. FOR EGR: STATS & DYNAM (LL
Additional Engineering Textbook Solutions
Thermodynamics: An Engineering Approach
Automotive Technology: Principles, Diagnosis, and Service (5th Edition)
Degarmo's Materials And Processes In Manufacturing
Thinking Like an Engineer: An Active Learning Approach (4th Edition)
Fundamentals of Aerodynamics
Heat and Mass Transfer: Fundamentals and Applications
- Clutch Mechanism 8. In the clutch mechanism shown, two flat circular disks of radius R are mounted so that they can be brought into contact causing a net frictional force. The contact pressure in general depends on the distance from the center and in one specific case may be modeled buy P(r) = Poe-kr, where k is a constant and r is the distance from the center of the discs. The integral cR F = 2m " P(r)rdr gives the total contact force between the discs. Cross-section a. In your own words explain where this formula comes from.arrow_forwardQ2. In a spring loaded governor of the Hartnell type, the mass of each ball is 5 kg and the lift of the sleeve is 50 mm. The speed at which the governor begins to float is 240 rpm, and at this speed the radius of the ball path is 110 mm. The mean working speed of the governor is 20 times the range of speed when friction is neglected. If the lengths of ball and roller arm of the bell crank lever are 120 mm and 100 mm respectively. If the distance between the center of pivot of bell crank lever and axis of governor spindle is 140 mm, determine the initial compression of the spring. If friction is equivalent to a force of 3O N at the .sleevearrow_forwardB r P F A UBC Engineering Your team is prototyping a simple braking system for your model car. The 3.4 kg wheel with a radius of r = rad 0.15 m is rotating at w = 18 - .A servo motor can apply a variable force F, which in its first two seconds of operation is equal to F = 10t N and afterwards is equivalent to a constant force of F = 20 N . If the coefficient of kinetic friction between the braking arm and the wheel is μ= 0.2, determine the time needed for the wheel to come to a full stop. The point of contact P between the wheel and the arm is a distance r = -0.2 + 0.26 ĵ m from point A. The force of the servo motor is applied at exactly half of the horizontal distance to A from the point of contact. Assume the wheel can be treated as a disk and that the braking arm is massless. t =arrow_forward
- : Tom is interviewing for a new job – a test driver. He was asked to determine whether a vehicle built to test the effects of Problem 1 high accelerations on people is safe. The car moving at a speed of 20 m/s runs into a piston that compresses the air in a cylinder and stops the car in 0.30 m. The 70-kg passenger stops in the same distance due to the force of shoulder straps and seat belts on her body. Draw free-body diagram for the passenger when he is slowing down to a stop inside a car. Assume that the force of the shoulder straps and seat belt is horizontal. Do not forget to draw acceleration vector as well. Choosing the passenger as your system and applying energy conservation law, find the work that the force of shoulder straps b. and seat belts did on his body in this process. C. Now that you have determined the work in the previous part, determine the magnitude of the average force of these restraints on the person during the stop.arrow_forwardFor the delivery truck shown: The mass of the truck is 4000 kg. The horizontal distance from the rear tires to the center of mass, G, is L1 = 3 m The vertical distance from the ground to G is d = 3m The horizontal distance from the rear tires to the front tires is L2 = 5 m. d The delivery truck is traveling at 20 m/s when the brakes are applied. The truck skids to a stop, so that the friction force is applied to the tires by the road.* The coefficient dynamic friction is uk = 0.60 *If it did not skid, then the friction force would be between the brake pads and the brake disc, which would be above the road. Calculate the distance that the truck travels before it stops. Use Σ MA = Ia + d x m*a for the following: 'O' Calculate the left side of this equation: Σ MA G L1 → L2 Calculate the right side of this equation: I*α + d x m*a d+ x m*a is from r x m*a (cross product), so, determine the sign by considering the cross product. Set the left and right right sides equal to each other and…arrow_forwardParvinbhaiarrow_forward
- How fast was the car moving the moment the driver removed their foot from the pedal?arrow_forwardThe 20-lb crate A rests on the surface. The coefficients of static and kinetic friction between the crate A and the surface are ?? = 0.15, ?? = 0.1. Determine the speed of crate A at t = 2 s if P = (?2 + 1.5?) lb where t is in seconds, using the method of Linear Impact and Momentum. Hint: first determine the moment when the crate starts to move.arrow_forwardThe lower block of mass m2 = 3.2 kg is pulled on by a rope with a tension force of 28 N. The upper block has mass m1 = 1.8 kg. The coefficient of kinetic friction between the lower block and the surface is 0.32. The coefficient of kinetic friction between the lower block and the upper block is also 0.32. What is the acceleration of the 3.2 kg block?arrow_forward
- Two blocks of the same mass, m, are connected by a light string and rest on the slope and in the air, respectively (0<8<90). The friction force on the mass siting on the slope will be 0 zero upward along the incline the same magnitude with the tension in the string downward along the incline E none of abovearrow_forwardFor a technology project, a student has built a vehicle, of total mass 6.00 kg, that moves itself. As shown, it runs on four light wheels. A reel is attached to one of the axles, and a cord originally wound on the reel goes up over a pulley attached to the vehicle to support an elevated load. After the vehicle is released from rest, the load descends very slowly, unwinding the cord to turn the axle and make the vehicle move forward (to the left as shown). Friction is negligible in the pulley and axle bearings. The wheels do not slip on the floor. The reel has been constructed with a conical shape so that the load descends at a constant low speed while the vehicle moves horizontally across the floor with constant acceleration, reaching a final velocity of 3.00î m/s. (a) Does the floor impart impulse to the vehicle? If so, how much? (b) Does the floor do work on the vehicle? If so, how much? (c) Does it make sense to say that the final momentum of the vehicle came from the floor? If…arrow_forwardQ.arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY