Acyclist comes to a skidding stop in 10m. During this process, the forceon the cycle due to the road is 200 N and is directy 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 foce and the displacement make an angle of `180^(@) (pi rad)` with each other. Thus, work done by the road,
`W_(r )= Fd cos theta`
`=200 xx 10 xx cos pi = -2000 J`
It is negative work that brings the cycle to a halt in accordance with WE theorem.