Question

cyclist comes on skidding stop in 10 m. During this process, the force on the cycle due to road is
200N and is directly opposed to motion. Can you recommend the amount of work does the road do on the
cycle and also how much work does the cycle do on the road? Justify your answer. Also let us consider a
body of mass 5 kg initially at rest is subjected to a force of 20N. If the body want to move, then can you
suggest and record the energy it needed to acquire at the end of 10seconds?

Answer 1

#.1

Let the distance(d) traveled by cyclist = 10 m in positive X direction and the force (F) on the cycle due to road = 200 N in the -X direction . Force and distance travelled are in opposite direction . Therefore angle between force and distance is ZERO becauce they are parallel to eachother.  

Work done by the force from road can be calculated by formula W = F.d.Cos = (-200N).(10m).Cos(00) = (-200N).(10m).1= -2000 N.m = - 2000 J

Considering the force remains th e same

Amount of workdone by cycle = W= F.d.Cos = 200N.10m. Cos(0) = 2000 J