Answer:
M_Train>> m_car a_train <a_car
Explanation:
To start the movement of the train or the car, the motorcycle applies a force on the wheels, which starts the acceleration in the case of the train, it has a much greater mass than that of the car, for which to obtain the same acceleration necessary a much greater force
a = F / m
as the mass of the train is greater than that of the car.
a_train <a_car
Something similar happens when the vehicles stop, the engine stops applying force forward and the brakes apply a force backward that creates a negative acceleration that slows down, again as the mass of the train is much greater than the of the car its negative acceleration is much less.
It is good to clarify that to compensate for this the trains have a braking system on all wheels
Answer:
The compression is 
.
Explanation:
A Hooke's law spring compressed has a potential energy
where k is the spring constant and 
the distance to the equilibrium position.
A mass m moving at speed v has a kinetic energy
.
So, in the first part of the problem, the spring is compressed a distance d, and then launch the mass at velocity 
. Knowing that the energy is constant.
If we want to double the kinetic energy, then, the knew kinetic energy for a obtained by compressing the spring a distance D, implies:
But, in the left side we can use the previous equation to obtain:
And this is the compression we are looking for
It will be 80 miles and it can be done only in 16 min
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