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Units of Speed

The unit of speed will depend upon the unit of distance and the unit of time.
If the distance covered is in metres and time taken is in seconds, then the unit of speed
will be expressed in metre per second or m/s. It is the standard unit of speed.
If the distance covered is in kilometres and time taken is in hours, then the speed will be

expressed in kilometre per hour or simply km/h. Using the relationship between speed,
distance and time, we can calculate any one if other two are given.
example: Neha travelled a distance of 440 km by car in 10 hours. Find the speed of car.
Solution: Distance travelled by car = 440 km
Time taken by car to travel 440 km = 10 hours

So, Speed = Distance ÷ Time = (440 ÷ 10) km/h = 44 km/h
Thus, the speed of car is 44 km per hour or 44 km/h.

Think and Answer
1. A man travelled a distance of 260 km by car in 4 hours. What is the speed of the car?
2. A train runs at the speed of 85 km per hour. How much distance does it cover in 3
hours?

Knowledge Desk
Galileo was the first scientist to measure speed as a function of distance over time.

Encapsulate
math
MeASUreMentS

Place Value Chart of Metric Measures Operations on Metric Measures

Addition:
Place Value Thousands Hundreds Tens Ones Tenths Hundredths Thousandths km hm dam m dm cm mm
1 1 1 2 4 3 4 0 = 24.340 m
Value 1000 100 10 1 10 100 1000 + 7 0 1 3 = + 7.013 m
Prefix Kilo... Hecto... Deca... Standard Deci... Cen�... Milli... 3 1 3 5 3 = 31.353 m
unit
Length km hm dam m dm cm mm Subtraction:
Weight kg hg dag g dg cg mg kg hg dag g dg cg mg
Capacity kL hL daL L dL cL mL 9 0 2 3 = 9.023 kg
– 3 3 4 5 = – 3.345 kg
5 6 7 8 = 5.678 kg
Conversion of Metric Measures
Multiplication: 4.345 L
For converting greater units into smaller units, multiply by 10 for × 7
every step as we move towards the right. division: 2 1 . 0 3 4 Quotient 30.415 L
× 10 × 10 × 10 × 10 × 10 × 10 2 4 2 . 0 6 8
4
Kilo Hecto Deca Standard Deci Centi Milli 0 2 Dividend = 42.068
= 2
2
Divisor
unit 0 0 6 Quotient = 21.034
÷ 10 ÷ 10 ÷ 10 ÷ 10 ÷ 10 ÷ 10 6 Remainder = 0
For converting smaller units to greater units, divide by 10 for 0 8
8
every step as we move towards the left. 0 Remainder
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