13. One track event is the 4 x 100-m relay in which
each athlete runs 100 m and
passes a baton (stick) to the
next runner who then runs
100 m, and so on for a total
of four runners. The runners
receiving the baton can start
moving before they receive
the baton. They must have
the baton in their hand when
they begin their 100-m run.
The average speed of the
400-m relay is less than the
average speed for a 100-m
sprint. In the 100-m sprint,
the runner begins from a
stopped position in starting
blocks. Use what you know
about acceleration, average
speed, and running starts to
explain how this is possible.

The act of moving from one place to another. a. locomotor b. aerobic c. stationary d. static

Two objects of different mass start from rest, are pulled by the same magnitude net force, and are moved through the same distance. the work done on object 1 is 900 j. after the force has pulled each object, object 1 moves twice as fast as object 2. how much work is done on object 2?

The center of a long frictionless rod is pivoted at the origin, and the rod is forced to rotate in a vertical plane with constant angular velocity \omega. write down the lagrangian for a bead of mass m threaded on the rod, using r as your generalized coordinate, where r, \phi are the polar coordinates of the bead. (notice that \phi is not an independent variable since it is fixed by the rotation of the rod tobe \phi = \omega * t) solve lagrange's equation for r(t). what happens if the bead is initially at rest at the origin? if it is released from any point ro > 0, show that r(t) eventually grows exponentially. explain your results in terms of the centrifugal force m* \omega ^2 *r.