Another WRONG solution provided: Module 4: One-Dimensional Kinematics; Example 3: Accelerating Car; question (d): x(t) does NOT = 100m + (2m/s^2)(t-10) in the interval 10s

Question

Another WRONG solution provided: Module 4: One-Dimensional Kinematics; Example 3: Accelerating Car; question (d): x(t) does NOT = 100m + (2m/s^2)(t-10) in the interval 10s<t<20s.  CORRECT answer: Velocity as a function of time is a 1st derivative of the Position as a function of time; and the equation for Position is the integral (or anti-derivative) of v(t); during the interval 10s<t<20s v(t)=20m/s; therefore, x(t)=20t + C during this interval; and C = -100; thus: the CORRECT piece-wise function for position vs. time when 10s<t<20s is: x(t)=20t - 100 and this equation is graphically correct.