ap-calculus-ab 2012 Q16

ap-calculus-ab · Usa · practice-exam Applied differentiation Kinematics via differentiation
A particle moves along the $x$-axis with its position at time $t$ given by $x ( t ) = ( t - a ) ( t - b )$, where $a$ and $b$ are constants and $a \neq b$. For which of the following values of $t$ is the particle at rest?
(A) $t = a b$
(B) $t = \frac { a + b } { 2 }$
(C) $t = a + b$
(D) $t = 2 ( a + b )$
(E) $t = a$ and $t = b$
A particle moves along the $x$-axis with its position at time $t$ given by $x ( t ) = ( t - a ) ( t - b )$, where $a$ and $b$ are constants and $a \neq b$. For which of the following values of $t$ is the particle at rest?

(A) $t = a b$

(B) $t = \frac { a + b } { 2 }$

(C) $t = a + b$

(D) $t = 2 ( a + b )$

(E) $t = a$ and $t = b$