By accident, a large plate is
dropped and breaks into three pieces.
the pieces fly apart parallel to the
floor. as the plate falls, its momentum
has only a vertical component and no
component parallel to the floor. after
the collision, the component of the to-
tal momentum parallel to the floor must
remain zero, since the net external force
acting on the plate has no component
parallel to the floor. using the data
shown in the drawing, find the masses
of pieces 1 and 2.