Mathematics 9709 · AS & A Level · Kinematics of motion in a straight line
Kinematics of motion in a straight line — practice question
A car with mass $900\text{ kg}$ travels along the straight horizontal road $ABCD$. On $AB$ and $BC$, the resistive force has constant magnitude $800\text{ N}$, while on $CD$ it has constant magnitude $R\text{ N}$. The engine supplies a constant power of $36\text{ kW}$.
(i)[3]
The car travels from $A$ to $B$ at steady speed in $120\text{ s}$. Determine the car’s speed and the length $AB$.
(ii)[3]
At $B$, the engine is turned off. Given that $BC$ is $450\text{ m}$, determine the car’s speed at $C$.
(iii)[4]
The car stops at $D$. The length $AD$ is $6637.5\text{ m}$. Determine the car’s deceleration and the value of $R$.
(c)[4]
The vehicle comes to rest at $D$. The distance $AD$ is $6637.5\,\text{m}$. Determine the deceleration of the car and the value of $R$.
Worked solution & mark scheme
This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Apply the power equation $P = Fv$: $36000 = 800v$” …