Question

In: Physics

A train has a mass of 4.82E+6 kg and is moving at 69.9 km/hr. The engineer...

A train has a mass of 4.82E+6 kg and is moving at 69.9 km/hr. The engineer applies the brakes, which results in a net backward force of 1.91E+6 N on the train. The brakes are held on for 28.2 s. What is the new speed of the train?

How far does it travel during this period?

Solutions

Expert Solution

Speed of the train = 69.9 km/hr = 19.42 m/s

Mass of the train = 4.82 x 106 kg

Backward acceleration of the train = (1.91 x 106)/(4.82 x 106) = 0.4 m/s2

So, velocity of train after 28.2 s is

                         

Now we know that

                           

Putting all the values in this equation, we get

                         

                   or,    

Hence, the train will travel nearly 386 meters in this time period.

For any doubt please comment.


Related Solutions

A train car with mass m1 = 576 kg is moving to the right with a...
A train car with mass m1 = 576 kg is moving to the right with a speed of v1 = 7 m/s and collides with a second train car. The two cars latch together during the collision and then move off to the right at vf = 4.4 m/s. A)What is the initial momentum of the first train car? B)What is the mass of the second train car? C)What is the change in kinetic energy of the two train system...
A train, A, with a mass of 19,000 kg is travelling at 90 km/h when it...
A train, A, with a mass of 19,000 kg is travelling at 90 km/h when it strikes a second train, B, which has a mass of 17,000 kg and is moving in the same direction at a speed of 43.2 km/h. If the coefficient of restitution for the collision is 0.87 and all resistances to motion are negligible, then (i) calculate the speed of the trains A and B immediately after the impact. (ii) as a result of damage during...
twoautomobiles of 840 kg and 1050 kg collide head on while moving at60 km/hr...
two automobiles of 840 kg and 1050 kg collide head on while moving at 60 km/hr in opposite directions. after they collision the automobiles remain locked together. find the velocity of the wreck immediately after the collision. also, find the kinetic energy of the two-car system before and after the collision
A meteor with a mass of 1 kg moving at 20 km/s collides with Jupiter's atmosphere....
A meteor with a mass of 1 kg moving at 20 km/s collides with Jupiter's atmosphere. The meteor penetrates 100 km into the atmosphere and disintegrates. What is the average force on the meteor once it enters Jupiter's atmosphere (Ignore gravity). *The answer is 2 x 10^3 N but I have no idea why.
6) A meteor of mass 575 kg has speed 90.0 m/s when it is 800 km...
6) A meteor of mass 575 kg has speed 90.0 m/s when it is 800 km above the surface of the Earth. It is falling vertically and strikes a bed of sand in which it is brought to rest in 3.25 m. Ignore the effects of air resistance. a) What is its speed just before striking the sand? b) How much work does the sand do to stop the meteor? c) What is the average force exerted by the sand...
A truck of mass 1200 kg is moving at 20m/s downhill on a 6-degree incline  It has...
A truck of mass 1200 kg is moving at 20m/s downhill on a 6-degree incline  It has a forward force of 800 N due to the engine and a 300 N retarding force of friction. What is the velocity of the truck after 10 seconds? What is the coefficient of friction? Answer in 3 decimal places, and include full equation please.
(a) A toy car1 has a mass of 1.6 kg and is moving with a velocity...
(a) A toy car1 has a mass of 1.6 kg and is moving with a velocity of 6.0 m/s to the right. It collides with a second car2 (mass 2.4 kg). The cars stick together. After the collision, both cars move with a velocity of 1.5 m/s to the left. (a) How fast and in what direction was car2 traveling before the collision? (b) Calculate the total kinetic energy of the system before and after the collision.
A plane with a speed of 800.0 km/hr due east passes directly above a train traveling...
A plane with a speed of 800.0 km/hr due east passes directly above a train traveling due southeast at 100.0 km/hr on a straight level road. The altitude of the aircraft is 10.0 km. How fast is the distance between the plane and the train increasing 45 s after the aircraft passes directly above the train?
Train driving 5 % uphill (2.9o) with speed 120 km/h. Train total mass is 100 000...
Train driving 5 % uphill (2.9o) with speed 120 km/h. Train total mass is 100 000 kg. The gear ratio is 1 (no transmission) and the train wheel diameter is 1 m. (Give the answer of accuracy of at least three significant digits.) Calculate the required torque: Answer kNm Calculate the required power:
A 1,000-kg car moving east at 90 km/h collides head-on with a 1,500-kg car moving west...
A 1,000-kg car moving east at 90 km/h collides head-on with a 1,500-kg car moving west at 50 km/h, and the two cars stick together. (a) Which way does the wreckage move and with what initial speed? (b) How much KE is lost in the collision?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT