A cyclist comes to a skidding stop in 10 m. During this process, the force on the cycle is 200N directly opposed to the motion.
How much work does the road do on the cycle ?

Explanation

Work done on the cycle by the road is the work done by the stopping (frictional) force on the cycle due to the road
The stopping force and the displacement make an angle of `180^(@)` (`pi` red) with each other.
Thus, work done by the road.
`W_(r) = Fd cos theta = 200 xx 10 xx cos pi = - 2000 J`
It is this negative work that brings the cycle to a halt in accordance with WE theorem