help if you know the correct answer
Answers
21. option b. Frictional force is a contact force (rest are non contact)
22. option b. lesser (when the surface is smoother there will be less number of surface irregularities compared to a rough surface hence, interlocking of surface irregularities is lesser, so frictional force is lesser here, as the amount of force required to overcome friction here is lesser compared to a rough surface)
23. option d. all of these (by providing wheels and lubricating, there is no direct contact between the surfaces, so the irregularities interlocking is avoided to a great extent)
24. option b. minimize (drag is the frictional force applied by a fluid on any object accelerating through it, so by providing a streamlined body, we are minimizing the drag)
25. option b. fulcrum
26. option b. non contact
27. (I am not so sure, I don't want to provide the wrong answer, so check up with that one alone)
anyways,
hope it helps
have a great day!