When Mustafa threw a beach ball to his friend, its horizontal velocity changed as it traveled through the air.
The relationship between the elapsed time, ttt, in seconds, since Mustafa threw the ball, and its horizontal velocity, V(t)V(t)V, left parenthesis, t, right parenthesis, in \text{cm/s}cm/sstart text, c, m, slash, s, end text, is modeled by the following function:V(t)=4⋅(0.81)t

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)