At a time t seconds after it is thrown up in the air, a tomato is at a height of f(t) = -4.9t^2 + 25t + 3 meters.

(a) What is the average velocity of the tomato during the first 1.7 seconds? Include units.

I know the units are m/sec but I can't get the average velocity!

(b) Find the instantaneous velocity of the tomato at t = 1.7. Include units.

It's 8.34 m/sec.

(c) What is the acceleration at t = 1.7?

-9.8 m/sec^2

(d) How high does the tomato go?

34.89 m

(e) How long is the tomato in the air?

I can't get this!! _______ sec

I'm so lost. Thank you =)