A particle moves according to the law of motion
\(s = t ^ { 3 } - 7 t ^ { 2 } + 5 t , \quad t \geq 0\)
where \( t \) is measured in seconds and \( s \) in feet.
a.) Find the velocity at time \( t \) . Answer:
b.) What is the velocity after \( 3 \) seconds? Answer:
c.) When is the particle at rest? Enter your answer as a comma separated list. Enter None if the parcicle is never at rest. Answer:
d.) When is the particle moving in the positive direction?
When \( 0 \leq t < \) ___and \(t> \)___