(1)s=(1/3)t^3−5t^2+25t+3

(1)s=(1/3)t^3−5t^2+25t+3
Acceleration at time t =_____?
(2)A particle moves along a straight line and its position at time t is given by s(t)=t^4−6t+18,t≥0.where s is measured in feet and t in seconds.
Find the total distance________?traveled during the first 8 seconds.
(3) If a ball is thrown vertically upward from the roof of 32 foot building with a velocity of 16ft/sec,its height after t seconds is s(t)=32+16t−16t^2.
What is the velocity of the ball when it hits the ground (height 0)?
(4)A spherical balloon is being inflated.Find the rate of increase (with respect to the radius r) of the surface area (S=4πr^2) when:
r=2 inches → Rate of increase =______?
r=3 inches → Rate of increase =______?
r=6 inches → Rate of increase =______?