Answer :
Final answer:
Cutting out the brakes in four cars of a ten-car train will result in decreased braking efficiency due to the reduction in available braking material to convert energy and slow the train.
Explanation:
The primary consequence of cutting out the brakes in four cars of a ten-car train is decreased braking efficiency. This is because the braking system's ability to apply frictional force to slow down the train is reduced. More specifically, the conversion of gravitational potential energy into internal energy of the brake material, crucial for decelerating the train, is diminished due to fewer brakes being involved.
Consequently, there is less material to absorb energy, leading to a decrease in the efficiency of the entire system's ability to slow down or stop.