Hi there!
a. Find the displacement by plugging in the values of the interval:
f(2) - f(0) = 0 - 2 = -2 meters.
Average velocity is the slope, thus:
The average velocity for the interval is -1 m/s.
b. To find the speed at the endpoints, we must take the derivative to get the velocity equation:
f(t) = t² - 3t +2
f'(t) = 2t - 3, at t = 0, speed = |-3| = 3 m/s. At t = 2, speed = 2(2) - 3 = 1 m/s.
Acceleration is the second derivative, thus:
f''(t) = 2. The acceleration is 2 m/s² for both endpoints.
c. When the body changes direction, the first derivative changes signs. Thus:
0 = 2t - 3
3 = 2t, t = 1.5 sec. This is where the body changes direction.
