Time needed for superman to stop the train

AI Thread Summary
To determine the time Superman needs to stop the train, first calculate the force experienced by a passenger using their weight and the given force factor. This force can be used to find the deceleration of the train by applying Newton's second law (F=ma). Next, convert the train's speed from km/hr to m/s for accurate calculations. Finally, use the kinematic equations to find the time required for Superman to bring the train to a complete stop. The solution involves understanding the relationship between force, mass, and acceleration in the context of the train's momentum.
zhenyazh
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hi,
can some one give me an outline of how to solve the following question?

thanks

Superman (mass=84.0 kg) must fly into a train (mass = 18079 kg) traveling at 75.0 km/hr to stop it.
Calculate the minimum time Superman must take to stop the train, if the passengers experience an average horizontal force of 0.420 their own weight.
 
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If the train is stopped, the passengers have also stopped.
Use F=ma on a passenger
 

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