A cyclist comes to a skidding stop in \(10 \mathrm{~m}\). During this process, the force on the cycle due to…
A cyclist comes to a skidding stop in \(10 \mathrm{~m}\). During this process, the force on the cycle due to the road is \(200 \mathrm{~N}\) and is directly opposite to the motion. How much work does the road do on the cycle?
\(2000 \mathrm{~J}\)
\(-2000 \mathrm{~J}\)
\(-1000 \mathrm{~J}\)
0
Solution
Displacement travelled by cyclist to reach skidding stop, \(s=10 \mathrm{~m}\)
Force on the cyclist due to road,
\(F=200 \mathrm{~N}\)
Since, force is applied directly opposite to motion (or displacement), hence \(\theta=180^{\circ}\)
\(\therefore\) Work done by the road on the cycle
\(W=F s \cos \theta=200 \times 10 \times \cos 180^{\circ}=-2000 \mathrm{~J}\)