un sistema se realiza un trabajo de -100 Joules y éste libera -40 calorías hacia los alrededores ¿Cuál es la variación en su energía interna en Joules ?

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i.e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i.e. include the distance traveled to the first encounter)

1kg of water needs to recieve 4200j of energy to go from 90 degrees to 91 degrees. what is the specific heat capacity of water? what are the units?

The field lines around one end of a bar magnet are shown below based on the diagram, what can you conclude about the pole of the magnet? a.is a south pole because the field hnes spread out from this end b.a north pole because the field lines spread out from this end c.a nouth pole because the field lines enter the magnet at this end d.is a north pole because the field lines enter the magnet at this end