Concept explainers
A light train made up of two cars is traveling at 90 km/h when the brakes are applied to both cars. Knowing that car A has a mass of 25 Mg and car B a mass of 20 Mg, and that the braking force is 30 kN on each car, determine (a) the distance traveled by the train before it comes to a stop, (b) the force in the coupling between the cars while the train is slowing down.
Fig. P12.12
Want to see the full answer?
Check out a sample textbook solutionChapter 12 Solutions
Vector Mechanics for Engineers: Statics and Dynamics
Additional Engineering Textbook Solutions
Manufacturing Engineering & Technology
Fundamentals Of Thermodynamics
Thinking Like an Engineer: An Active Learning Approach (4th Edition)
Automotive Technology: Principles, Diagnosis, And Service (6th Edition) (halderman Automotive Series)
Engineering Mechanics: Statics
Heat and Mass Transfer: Fundamentals and Applications
- A 2000-kg automobile starts from rest at point A on a 6° incline and coasts through a distance of 50 m to point B. The brakes are then applied, causing the automobile to come to a stop at point C, 20 m from B. Knowing that slipping is impending during the braking period and neglecting air resistance and rolling resistance, determine the speed of the automobile at point B. The speed of the automobile at point B is ___ m/s.arrow_forwardIn order to determine the weight of a freight train of 40 identical boxcars, an engineer attaches a dynamometer between the train and the locomotive. The train starts from rest, travels over a straight, level track, and reaches a speed of 30 mi/h after three minutes. During this time interval, the average reading of the dynamometer is 120 tons. Knowing that the effective coefficient of friction in the system is 0.03 and air resistance is negligible, determine (a) the weight of the train (in tons), (b) the coupling force between boxcars A and B.arrow_forwardIt is shown in mechanics of materials that the stiffness of an elastic cable is k=AE It is shown in mechanics of materials that the stiffness of an elastic cable is L, where A is the cross-sectional area of the cable, E is the modulus of elasticity, and L is the length of the cable. A winch is lowering a 4000-lb piece of machinery using a constant speed of 3 ft/s when the winch suddenly stops. Knowing that the steel cable has a diameter of 0.4 in., E = 29 × 106 lb/in2, and when the winch stops L = 30 ft, determine the maximum downward displacement of the piece of machinery from the point it was when the winch stopped.arrow_forward
- A 1-kg block B is moving with a velocity v0 of magnitude v0 = 2 m/s as it hits the 0.5-kg sphere A , which is at rest and hanging from a cord attached at 0 . Knowing that μk= 0.6 between the block and the horizontal surface and e = 0.8 between the block and the sphere, determine after impact (a) the maximum height h reached by the sphere, (b) the distance x traveled by the block.arrow_forwardTwo swimmers A and B, of weight 190 lb and 125 lb, respectively, are at diagonally opposite corners of a floating raft when they realize that the raft has broken away from its anchor. Swimmer A immediately starts walking toward B at a speed of 2 ft/s relative to the raft. Knowing that the raft weighs 300 lb, determine (a) the speed of the raft if B does not move, (b) the speed with which B must walk toward A if the raft is not to move.arrow_forwardAn advanced spatial disorientation trainer allows the cab to rotate around multiple axes as well as to extend inwards and outwards. It can be used to simulate driving, fixed-wing aircraft flying, and helicopter maneuvering. In one training scenario, the trainer rotates and translates in the horizontal plane where the location of the pilot is defined by the relationships where r,0, and t are expressed in feet, radians, and seconds, respectively. Knowing that the pilot has a weight of 175 lbs, (a) determine the magnitude of the resulting force acting on the pilot at t= 5 s, (b) plot the magnitudes of the radial and transverse components of the force exerted on the pilot from 0 to 10 seconds.arrow_forward
- A 1.36 kg particle is acted upon by a force F ti tj 2 ˆ 24cos2 ˆ 20sin where F is expressed in Newton and t in seconds. Determine the magnitude and direction of the velocity of the particle at t = 6 s, knowing that its velocity is zero at t = 0.arrow_forwardA satellite will travel indefinitely in a circular orbit around a planet if the normal component of the acceleration of the satellite is equal to g(R/r)2, where g is the acceleration of gravity at the surface of the planet, R is the radius of the planet, and r is the distance from the center of the planet to the satellite. Knowing that the diameter of the sun is 1.39 Gm and that the acceleration of gravity at its surface is 274 m/s2, determine the radius of the orbit of the indicated planet around the sun assuming that the orbit is circular.arrow_forwardPrinciple of Angular Impulse and Momentum To apply the principle of angular impulse and momentum to find final speed and the time to reach a given speed. As shown, ball B, having a mass of 10.0 kg, is attached to the end of a rod whose mass can be neglected. Finding the final speed of the ball If the rod is 0.550 m long and subjected to a torque M=(1.95t2+3.75) N⋅m, where t is in seconds, determine the speed of the ball when t=4.80 s. The ball has a speed of v=2.25 m/s when t=0 Finding the time needed to reach a specific speed If the shaft is 0.250 m long, the ball has a speed of v=2.85 m/s when t=0, and the rod is subjected to a torque M=(3.40t+2.15) N⋅m, where t is in seconds, determine the time it will take for the ball to reach a speed of 5.80 m/s.arrow_forward
- A 180-lb man and a 120-lb woman stand side by side at both ends of the 300-lb boat, ready to dive, each with a 16-ft/s speed relative to the boat. Determine the speed of the boat after they both dive, if (a) the woman dives first, (b) the man dives first. (show your solution) choices of correct answer: 3.0723 km/hr ; 0.251 km/hr 13.0723 km/hr ;1.251 km/hr 10.095 km/hr; 10.2815 km/hr 18.0723 km/hr; 0.521 km/hr 0.251 km/hr; 8.0723 km/hrarrow_forwardA 1400-kg automobile starts from rest and travels 400 m during a performance test. The motion of the automobile is defined by the relation x= 4000 ln(cosh 0.03t), where x and t are expressed in meters and seconds, respectively. The magnitude of the aerodynamic drag is D = 0.35v2 , where D and v are expressed in newtons and m/s, respectively. Determine the power dissipated by the aerodynamic drag when (a) t= 10 s, (b) t= 15 s.arrow_forwardA constant force P is applied to a piston and rod of total mass m to make them move in a cylinder filled with oil. As the piston moves, the oil is forced through orifices in the piston and exerts on the piston a force of magnitude kv in a direction opposite to the motion of the piston. Knowing that the piston starts from rest at t= 0 and x = 0, show that the equation relating x, v, and t, where x is the distance traveled by the piston and v is the speed of the piston, is linear in each of these variables.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