Sebastián se encuentra en una parada de trenes. El tren n° 15 pasa sin detenerse a una velocidad de 35 km/h. Si situamos el sistema de referencia en Sebastián, ¿el tren n° 15 está en reposo o en movimiento?

the train is moving relative to the boy

Explanation:

When the train is on the road, it moves with respect to the Earth at a speed of 35 km / h. When we arrive at the station we change the reference system from the ground to the boy who is in the station, therefore the speed of the train can change

               v ’= v + u

where v is the speed of the train with respect to the boy, v is the speed with respect to the ground and u the speed of the boy with respect to the ground

In general, the people in the station are still, that is, their speed with respect to the ground is zero, consequently the speed of the train does not change.

The correct answer is that the train is moving relative to the boy.

answer would be letter choice (a),   a ball resting on a shelf. would be another example of potential energy   >   stored energy > not moving.

a ball spinning on a finger   >   kinetic energy > moving energy

a ball rolling on the ground   >   kinetic energy   > moving energy

a   ball flying through the air   > kinetic energy   >   moving energy

hope that                                         : )