(i)[2]
Calculate the distance travelled by the sprinter in the first $42\,\text{s}$ of the race.
(ii)[3]
Show that $V = 7.84$.
(iii)[2]
Calculate the deceleration of the sprinter in the last $10\,\text{s}$ of the race.
Mathematics 9709 · AS & A Level · Kinematics of motion in a straight line
Kinematics of motion in a straight line — practice question
A sprinter takes part in a $400\,\text{m}$ race, and his total running time is $52\,\text{s}$. The diagram gives the velocity-time graph for the sprinter’s motion. He begins from rest and increases his speed uniformly to $8.2\,\text{m s}^{-1}$ in $6\,\text{s}$. He then keeps a speed of $8.2\,\text{m s}^{-1}$ for $36\,\text{s}$ before slowing down uniformly to a speed of $V\,\text{m s}^{-1}$ at the finish.