A particle moves along a line so that its position at any time t >= 0 is given by the function -t^3 + t^2 + 5t + 3, where p is measured in feet and t is measured in seconds.

1. Find the displacement during the first four seconds.

My answer: 75 ft

2. Find the average velocity during the first four seconds.

My answer: -7 ft/sec

3. Find the instantaneous velocity when t = 4.

My answer: -35 ft/sec

4. Find the acceleration of the particle when t = 4.

My answer: -22 ft/sec^2

5. At what value of t does the particle change directions?

My answer: t = 1 and t = 5/3

6. How far does the particle travel during the first six seconds?

My answer: About 166 feet