Astudent sits atop a platform a distance h above the ground. he throws a pingpong ball horizontally with a speed v. however, a wind blowing parallel to the ground gives the pingpong ball a constant horizontal acceleration with magnitude a. this results in the pingpong ball reaching the ground directly under the student.
determine the height h in terms of v, a, and g. this is a somewhat unphysical problem in that you can ignore the effect of air resistance on the vertical motion, but clearly the wind has a big affect on the horizontal motion.

A-4.60 μc charge is moving at a constant speed of 6.80×105 m/s in the +x−direction relative to a reference frame. at the instant when the point charge is at the origin, what is the magnetic-field vector it produces at the following points.

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

Astudent weighing 700 n climbs at constant speed to the top of an 8 m vertical rope in 10 s. the average power expended by the student to overcome gravity is most nearly