A boy pulls a wagon containing his sister a distance of 40.0 m with a force of 50 N at an angle of 15.0 to the horizontal, as shown in the figure below. Treat here the effect of friction to be negligible. What is the work done on the wagon by the boy? Include units as appropriate. What is the kinetic energy difference (entered as a positive value) between a truck of mass 20000 kg travelling along a highway at 90 km/h and an astronaut of mass 85 kg in orbit travelling at 27500 km/h? Include units as appropriate. KE diff = Using energy considerations (namely, by finding the work done by all forces) find the magnitude of the average force a 60.0 kg runner applies to the track (and therefore the track also applies to the runner) to accelerate from 1.5 m/s to 8.0 m/s over a distance of 15.0 m while experiencing a constant opposing headwind force of magnitude 30 N. Include units as appropriate. Fav =