Question

the distance between Jalandhar and ambala railway stations is 120 km and a passenger train covers this distance in 3 hrs . construct a plain scale to measure time upto single minute . the rf of the scale is 1/20000 . mark on the scale, the distance covered by the train in 42 minutes ,32 minutes and 12 minutes.​

Answer 1

i got this from net

CONSTRUCTION:-

a) 210 km in 7 hours. Means speed of the train is 30 km per hour ( 60 minutes)

•  Length of scale = R.F.  x   max. distance per hour

                                      = 1/ 2,00,000   x   30km

                          = 15 cm

b) 15 cm length will represent 30 km and 1 hour i.e. 60 minutes.

•     Draw a line 15 cm long and divide it in 6 equal parts. Each part will represent 5 km and 10 minutes.

c) Sub divide the first part in 10 equal parts, which will represent second unit or fraction of first unit.

•    Each smaller part will represent distance traveled in one minute.

d) Place ( 0 ) at the end of first unit. Number the units on right side of Zero and subdivisions  

•    on left-hand side of Zero. Take height of scale 5 to 10 mm for getting a proper look of scale.

e) Show km on upper side and time in minutes on lower side of the scale as shown.

•     After construction of scale mention it’s RF and name of scale as shown.

f) Show the distance traveled in 29 minutes, which is 14.5 km, on it as shown.