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{\obeylines%
WY5V8181
HR
}
\noindent(a)
Speed is absolute velocity (i.e. regardless of direction). Both A and B
have increasing absolute distance from the x-axis at every time shown on
the graph, so neither has decreasing speed.
\noindent(b)
At $t=0$, $t=2$, A and B are moving at the same speed because their
lines on the graph intersect.
\noindent(c)
Object A.
\noindent(d)
$$W = \Delta E.$$
The initial velocities of both objects are zero, so their initial
energies are zero, and $$W = E_f = {1\over2}mv^2.$$ Because
$m_A = m_B,$ and $$|v_A| > |v_B| \to v_A^2 > v_B^2\hbox{ at $t=4$},$$
object A has more energy and has thus had more net work done to it.
\bye
|
