Mathematics 9709 · AS & A Level · Kinematics of motion in a straight line

Kinematics of motion in a straight line — practice question

A particle $P$ travels along a straight line and passes through a point $O$. Its velocity $v\ \text{m s}^{-1}$ at time $t$ seconds after passing $O$ is given by $v = \frac{9}{4} + \frac{b}{(t + 1)^2} - ct^2,$ where $b$ and $c$ are positive constants. When $t = 5$, the velocity of $P$ is zero and the acceleration is $-\frac{13}{12}\ \text{m s}^{-2}$.
(a)[5]

Show that $b = 9$ and find $c$.

(b)[5]

Since the velocity of $P$ is zero only when $t = 5$, find the distance travelled in the first $10$ seconds of motion.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Uses $v(5)=0$ to produce an equation in $b$ and $c$, for example $0=\frac94+\frac{b}{(5+1)^2}-c\times5^2$

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