Mathematics 9709 · AS & A Level · Newton's laws of motion
Newton's laws of motion — practice question
A racing cyclist, with a combined mass together with his cycle of $75\,\text{kg}$, produces power at a rate of $720\,\text{W}$ while travelling along a straight horizontal road. The resistive force opposing the cyclist’s motion is constant and has magnitude $R\,\text{N}$.
(i)[3]
At the instant when his speed is $12\,\text{m s}^{-1}$ and his acceleration is $0.16\,\text{m s}^{-2}$, determine the value of $R$.
(ii)[2]
Given that the cyclist’s acceleration is positive, show that his speed is less than $15\,\text{m s}^{-1}$.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “States that $F=\frac{720}{12}$” …