im a medical guy ,so dont bash me if im wrong,just correct me.

 

if a train is coneected to 2 engines one of which has speed of 40 and other 60,and if both are started simultaneously what will be the speed of the train?

 

will it be 60

above 60

below 60 and above 40

1>it is 60 because 60 overrides 40.(my presumed ans)

2>abvove 60 because some load will be shared by 40 which helps to pull it

3>previosly a 40 engine was attached and now a >40 is attached ,so the speed will be above 40 but below 60

 

well i thought that 60 was right so where does the energy used up by 60 go?

Engines don´t have speeds, only powers. The rest of your post thus becomes useless due to improper definition of the problem (no offense, it´s just impossible to scientifically correctly answer the question without further assumptions). Nevertheless, any additional condition you could give (which must make sense, of course) will lead to conservation of energy (most likely due to friction of the wheels that rotate to fast or to slow on the tracks).