Question

please it's urgent solve all these questions all questions are from chapter motion and time please guys quick

Answer 1

answer 1.

boy speed is 4 km/h
and
reaches time is 30min

distance=speed×time

convert 4 km/h = 4000/60

4000/60×30=200m
=0.2km



2.Ans = distance between two station is 216 km


bus cover distance is 4 hours


= average speed = total distance travelled/total time taken

=216/4
=54 km/h

Answer 2

1.    v = 4km/h
        t = 30 min  = 0.5 h 
        s = v.t  = 4*0.5 = 2k m
2.Average speed  = total distance covered / total time taken = 216/4 = 54km/h
3.Relative velocity of car B w.r.t A = 50-40 = 10 km/h,
    time ,t = 3 h
     Hence, distance b/w A and B = 3*10 = 30km
4.   Distance covered in first 15 minutes =  40*(15/60) = 40*(1/4) = 10km
       and, distance covered in remaining  15 minutes = 60*(15/60) = 15km
       So, total distance = (10+15)km = 25km
5.Periodic motion - A motion which repeats itself after regular intervals of time, is called periodic motion. e.g.  (i)motion of a second's tip of a watch.
                                                          (ii)motion of earth around the Sun.