PhysicsLAB: The Jogger

The roads in Dr. J's neighborhood are slightly more crowded in the mornings these days since he has taken up jogging. The crowding comes from the crew that helps Dr. J get through this physical fit that is overrunning the country. J. Jr. marks off a new course each day while Timex mans the stopwatch. Tripod is there at the end supporting a tray of cereal, fruit, and bacon on his nose (his idea of a balanced breakfast). Dr. J does have one quirk - he doesn't use shoelaces. As a result, his shoes always look like they are ready to come apart when he finishes. (Don't most joggers finish with their tongues hanging out?) But alas, this is the day that Dr. J finally gets tired of it all. His course takes him through the local park, but a thick fog has decreased visibility. As a result, he runs into a swing made from an old tire suspended by a long rope. Dr. J experiences a new high as he and the tire rise 0.3 m above their initial level.

If Dr. J weighs 750 N and the mass of the tire is 10 kg, how fast was Dr. J running?

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