(d) The particle moves in the positive direction when its velocity has a positive sign. You know the particle is at rest when
and
, and because the velocity function is continuous, you need only check the sign of
for values on the intervals (0, 3) and (3, 6).
We have, for instance
and
, which means the particle is moving the positive direction for
, or the interval (3, 6).
(e) The total distance traveled is obtained by integrating the absolute value of the velocity function over the given interval:

which follows from the definition of absolute value. In particular, if
is negative, then
.
The total distance traveled is then 4 ft.
(g) Acceleration is the rate of change of velocity, so
is the derivative of
:

Compute the acceleration at
seconds:

(In case you need to know, for part (i), the particle is speeding up when the acceleration is positive. So this is done the same way as part (d).)
Answer:
20 inches
Step-by-step explanation:
Since the cape is trapezoid shaped and has an area of 600 in², the area of a trapezoid is given by
A =1/2(a + b)h where a = length along the top of the cape = 24 in, b = length along the bottom of the cape = 36 in and h = height of the cape
So, h = 2A/(a + b)
= 2 × 600 in²/(24 in + 36 in)
= 1200 in²/60 in
= 20 in
So, the height of the cape is 20 inches