A proton moves along the $x$ axis according to the equation $x=50 t+10 r^{2},$ where $x$ is in meters and $t$ is in seconds. Calculate (a) the average velocity of the proton during the first $3.0 \mathrm{~s}$ of its motion.
(b) the instantancous velocity of the proton at $t=3.0 \mathrm{~s}$, and (c) the instantancous acceleration of the proton at $t=3.0 \mathrm{~s}$. (d) Graph $x$ versus $t$ and indicate how the answer to (a) can be obtained from the plot. (c) Indicate the answer to (b) on the graph. (f) Plot $v$ versus $t$ and indicate on it the answer to (c).