Chapter 2 - Kinematics in One Dimension - Exercises and Problems - Page 64: 23

(a) $x = 7~m$ (b) $v = 7~m/s$ (c) $a = 4~m/s^2$

(a) $x(t) = 2t^2 -t+1$ At t = 2 s: $x = (2)(2~s)^2-(2~s)+1$ $x = 7~m$ (b) $v(t) = \frac{dx}{dt} = 4t-1$ At t = 2 s: $v = (4)(2~s)-1$ $v = 7~m/s$ (c) $a(t) = \frac{dv}{dt} = 4$ At t = 2 s: $a = 4~m/s^2$