Topics Discussed: acceleration; angular motion; human motion; kinematics; linear motion; spatial displacement; velocity.
Sections: Summary, Introductory Problems, Additional Problems, Additional Points, References, Annotated Readings, Related Web Sites.
"The greater the radius is between a given point on a rotating
body and the axis of rotation, the greater is the linear distance
undergone by that point during an angular motion (Figure 11-15).
This observation is expressed in the form of a simple equation:Two baseballs are consecutively hit by a bat. The first ball
is hit 20 cm from the bat's axis of rotation, and the second
ball is hit 40 cm from the bat's axis of rotation. If the
angular velocity of the bat was 30 rad/s at the instant
that both balls were contacted, what was the linear velocity of
the bat at the two contact points?A windmill-style softball pitcher executes a pitch in 0.65 s.
If her pitching arm is 0.7 m long, what are the magnitudes of the
tangential and radial accelerations on the ball just before ball
release, when tangential ball speed is 20 m/s? What is
the magnitude of the total acceleration on the ball at this point?..."