In the question two trains are of equal length 400 m and moves at a uniform speed of 72 km/h. train A is moving ahead of train B. If the train B has to overtake train A it should accelerate.

Train B’s acceleration is $1m/s^2$ and it accelerated for 50 seconds.

 $a=1 m/s^2$ 

t=50 s 

initial speed u=72km/h 

we have to convert this speed into m/s 

 $u=72 \times 5/18=20 m/s$ 

Distance covered in accelerating phase $S=ut+1/2 at^2$ 

 $=20 \times 50+1/2 \times 1 \times 50^2$ 

 $=1000+1250=2250 m$ 

If a train is just behind another, the distance covered by the train located behind during overtaking phase will be equal to the sum of the lengths of the trains.

Here length of train A+length of train $B=400+400=800 m$ 

Hence the initial distance between the trains = $2250-800=1450 m$ 

6 0

2 years ago

Why do nuclear power plants use fission rather than fusion to generate

kicyunya [14]

B. Fusion requires very high pressure and temperature.

Explanation:

Nuclear fusion is the combination of atomic nuclei into larger ones with the release of a large amount of energy.

Nuclear fission is the decay process in which a heavy nuclide is bombarded with with neutrons.

Both processes release a huge amount of energy.
But fusion produces far more energy.
The reason why nuclear fusion is not in use is because of the high pressure and temperature needed start it.
The activation energy is high and the energy barrier is very great.
Only the core of the sun naturally favors fusion

learn more:

transmutation brainly.com/question/3433940

#learnwithBrainly

5 0

2 years ago

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