plain scale
Plain Scale
Plain scale : this type of scale represents two units as a unit and it's sub-division.
Problems on plain scale
1] Draw a scale of 1 cm = 1m to read decimeters, to measure a maximum distance of 6 m. show on it a distance of 4 m and 6 dm.
CONSTRUCTION :
- Calculate R.F = [katex]\frac{Dimansion\ of \ drawing}{Dimension\ of\ objects}[/katex]
R.F = 1 cm / 1 m
= 1/100
length of scale = R.F × maximum distance
= 1/100 × 600 cm
= 6 cms
- Draw line 6 cm long and divide it into 6 equal parts. Each part will represent a larger division unit.
- subdivide the first part which will represent the second unit or fraction of the first unit.
- place (0) at the end of the first unit. Number the unit or right side of zero and subdivisions on the left-hand side of zero. Take height of scale 5 or 10 mm for getting a look of scale.
- After construction of scale mention it's RF and name of scale as shown.
- Show the distance 4 m and 6 dm on it as shown.
2] In a map 36 km distance is shown by a line 45 cms long. Calculate the R.F. and construct a plain scale to read kilometer and hectometers, for max. 12 km. Show a distance of 8.3 km on it.
CONSTRUCTION :
- Calculate R.F = [katex]\frac{Dimansion\ of \ drawing}{Dimension\ of\ objects}[/katex]
R.F = 45 cm / 36 km
= 45/36*1000
= 1/80,000
length of scale = R.F × maximum distance
= 1/80,000 × 12 km
= 15 cm
- Draw a line 15 cm long and divide it into 12 equal parts. Each part will represent a larger division unit.
- subdivide the first part which will represent the second unit or fraction of the first unit.
- place (0) at the end of the first unit. Number the unit or right side of zero and subdivisions on the left-hand side of zero. Take height of scale 5 or 10 mm for getting a look of scale.
- After construction of scale mention it's RF and name of scale as shown.
- Show the distance 8.3 km on it as shown.
3 ] The distance between the two stations is 210 km. A passenger train covers this distance in 7 hours. Construct a plain scale to measure time up to a single minute. R.F is 1/200,000 indicate the distance traveled by train in 29 minutes.
CONSTRUCTION :
- 210 km in 7 hours. means speed of the train is 30 km per hour ( 60 minutes )
Length of scale = R.F × max distance per hour
= 1/2,00,000 × 30 km
= 15 cm
- 15 cm length will represent 30 km and 1 hour i.e. 60 minutes. Draw a line 15 cm long and divide it into 6 equal parts, Each part will represent 5 km and 10 minutes.
- Sub-divide the first part in 10 equal parts. Which will represent the second unit or fraction of the first unit. Each smaller part will represent distance traveled in one minute.
- place (0) at the end of the first unit. Number the unit or right side of zero and subdivisions on the left-hand side of zero. Take height of scale 5 or 10 mm for getting a look of scale.
- Show km on the upper side and time in minutes on the lower side of the scale as shown. After construction of scale mention it's RF and name of scale as shown.
- Show the distance traveled in 29 minutes, which is 14.5 km, on it as shown
