Three railroad cars are pulled by a train engine at a constant speed. How does the tension pulling the last single car compare to tension pulling all three of the cars. There is friction involved.
To understand how the tension pulling the last single car compares to the tension pulling all three cars, let's break down the scenario and consider the forces involved.
When a train engine pulls a train, the force exerted by the engine generates tension in the connecting couplings between the cars. This tension is transmitted through the cars, ultimately reaching the last car.
In this case, we can assume that the train is moving at a constant speed. For this condition to be met, the total force applied by the engine must balance the frictional resistance between the train and the tracks.
When all three cars are connected, the tension generated by the engine is distributed among the cars, with each car experiencing a portion of the force.
However, when we detach the last single car from the rest of the train, the tension is now only applied to that car alone.
Considering friction, each car (including the last single car) experiences some resistance from the track surface. This resistance opposes the motion of the train and necessitates a force to overcome it.
In the case of the last single car, the tension pulling it needs to overcome the frictional force acting on that car alone. This means that the tension in the connecting coupling between the last car and the engine needs to be greater than the frictional force acting on the last car.
On the other hand, when all three cars are connected, the total tension generated by the engine is distributed among the cars, meaning that each car experiences a fraction of the tension. Consequently, the tension in the connecting couplings across all cars will be greater than the frictional force acting on each individual car.
In summary, the tension pulling the last single car will be greater than the tension pulling all three cars combined due to the distribution of forces across multiple cars and the effects of friction.