Bowling Ball Forces
Here are the actual position vs time and velocity vs time graphs for our bowling ball rolling across the classroom
floor, recorded by an ultrasonic motion detector. The tape mark is in the middle of the room, far from the
bowler. Make color-coded vertical regions to indicate when the hand is pushing on the ball and when the foot is
stopping the ball.
Interval when the ball
is being accelerated
forward by hand:
“breakfast!”
1. Draw all the forces on
the ball when the hand is
accelerating it forward.
Color-code ‘em!
2. Now draw all the forces on the ball
when it is crossing the tape mark.
3. Finally, draw all the forces on the ball
while it is being stopped by the foot.
Instant when ball
crosses the tape mark:
this is the instant we
are most interested in.
Interval when the ball
is being stopped by
the foot: “dinner!”