The engine of a locomotive exerts a constant force of 8.1*10^5 n to accelerate a train to 68 km/h. determine the time (in min) taken for the train of mass 1.9*10^7 kg to reach this speed from rest.

443.1 s

Explanation:

Given

Engine of a locomotive exerts a force of

Mass of train

Final speed (v)

F=ma

so

and acceleration is

Explanation:

It is given that,

Force acting on the engine,

Initial speed of the engine, u = 0 (at rest)

Final speed of the engine, v = 68 km/h = 18.88 m/s

Mass of the train,

We need to find the time taken by the train. Firstly, we will find the acceleration of the engine from Newton's second law of motion as :

Now using first equation of motion to find time taken as :

t = 449.52 seconds

or

t = 7.49 minutes

So, the time taken for the train to reach this speed is 7.49 minutes. Hence, this is the required solution.

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.