Need help urgently on the following question. ?

Question

Really confused with a and b. I’f someone could help that would be great. 

Answer 1

This question makes no sense at all.  Your teacher is an idiot.  What is "x", is it time, or is it a spatial coordinate?  "At 2.13 seconds" makes no sense since there is no "t" in the original equation.  

If he/she really meant y = 17t^3 - 2t + 2, the speed would be

dy/dt = 51t^2 - 2, so the object would not be in motion 

when t = sqrt(2/51).

The speed is dy/dt = 51t^2 - 2, as we said above.  Plug in t = 2.13s.

The acceleration is d2y/dt2 = 102t, again plug in t = 2.13s.

But you were never told what units the "y" is being measured in, so you'd still have no idea what to say about the speed and acceleration.  Is the speed m/s, ft/s, or leagues per second?  

Go to your another math or science teacher at your school to complain about this moron.