A train has a 500,000 kg engine towing 20 cars on a level track. Each car has a mass of 100,000 kg. The train is speeding up at a rate of 0.1 m/sec2. The wheels of the train do not skid. What is the minimum coefficient of static friction between the engine wheels and the track? (Note: I do not want you to look up the coefficient of static friction between steel and steel. Instead use FBD’s to find the smallest coefficient that will work.)
1. A train has a 500,000 kg engine towing 20 cars on a level track. Each car has a mass of 100,000 kg. The train is speeding up at a rate of 0.1 m/sec2. The wheels of the train do not skid. What is the minimum coefficient of static friction between the engine wheels and the track? (Note: I do not want you to look up the coefficient of static friction between steel and steel. Instead use FBD’s to find the smallest coefficient that will work.)
2. A train has a 500,000 kg engine towing 20 cars on a level track. Each car has a mass of 100,000 kg. The train is speeding up at a rate of 0.1 m/sec2. The wheels of the train do not skid. What is the force in the coupling between the 10th and 11th cars (counting the car immediately behind the engine as car 1)?
3. Three rectangular boxes are stacked on top of each other. All the boxes have the same mass of 1.2 kg. The kinetic coefficients of friction between the boxes are all 0.6 and the static coefficient of friction is 0.7. There is no friction between the bottom box and the floor. A rope is attached to the lowest box and pulls on the lowest box with a force of 5.0 N. Is the friction between the boxes static or kinetic?
4. Three rectangular boxes are stacked on top of each other. All the boxes have the same mass of 1.2 kg. The kinetic coefficients of friction between the boxes are all 0.6 and the static coefficient of friction is 0.7. There is no friction between the bottom box and the floor. A rope is attached to the lowest box and pulls on the lowest box with a force of 5.0 N.
Suppose the force on the rope is slowly increased. How large can the force be before the boxes begin to slide on each other?
Trending now
This is a popular solution!
Step by step
Solved in 2 steps with 5 images
