An object's two dimensional velocity is given by #v(t) = ( 3t^2 - 5t , t )#. What is the object's rate and direction of acceleration at #t=2 #?
I'm guessing they're using normal convention replaced by brackets.
So, in vectorial form,
Acceleration is the time derivative of velocity, so you go that.
I'm sure you know differentiation, hence we'll get acceleration
We need to find acceleration at time
In the end, you'll get why the answer is as given in the box.