Study the scenario.
Two trains are moving along a train track at 45 mph towards each other. The first train has twice the mass of the second train. The trains spot each other, and apply the brakes at the same time. Both come to a stop, and disaster is narrowly averted.
Which of the following choices correctly describes the work done in the situation?
No work was done on the trains because an external force was applied to the trains in order to change their velocity. Only the velocity changed, no change in displacement occurred.
No work was done on either train because the force applied to each train was not in the same direction as their motion.
Work was done on the two trains because the trains gained kinetic energy as they slowed down. The first train had the most work done on it.
Negative work was done on both of the trains because a force was applied over a distance in order to change their velocity, and the forces were applied in a direction opposite to their motion.
is it the third one?
1 answer
1 answer