Time and Distance
Important Terms & Formula
Distance
The length of path covered by an object is called DISTANCE.
Distance is generally denoted by "S" or "s" or "D" or "d".
The SI unit of distance is "meter" and denoted by "m". The long distance is measured in "Kilo Meter" and abbreviated as "Km".
1000 meter = 1 kilo meter
Time
Time taken to cover a particular distance is known as "TIME".
Time is generally denoted by "t" or "T".
The SI unit of time is "second".
1 hour = 60 minute
1 minute = 60 second
Speed
The distance covered in unit time is called "SPEED".
Speed is generally denoted by "v".
Important Formula
Distance = Time × Speed
Time = `(Distance)/(Speed)`
Speed = `(Distance)/(Time)`
Average Speed = `(Total\ distance\ covered)/(Total\ Time\ Taken)`
Solved Examples
Calculation of distance when speed and time are given.
Question (1) How much distance is covered by a cyclist running at a speed of 5 km/hour in 3 hour?
Solution
Given, Speed of the cyclist (v) = 5 km/hour
Time (t) = 3 hour
Thus, distance (s) = ?
We know that,
Distance = Speed × Time
= 5 km/h × 3 h
= 15 km
Thus, distance covered by the cyclist in given time = 15 km Answer
Alternate Method (Unitary method)
As given, the speed of the cyclist = 5 km/hour
This means the cyclist covers 5 km in 1 hour.
∵ The distance covered by the cyclist in 1 hour = 5 km
∴ The distance covered by the cyclist in 3 hour = 5 km × 3
= 15 km
Thus, distance covered by the cyclist in given time = 15 km Answer
Question (2) The speed of a car is 15 km/hour. Find the distance covered by the given car in 5 hour.
Solution
Given, Speed of the car (v) = 15 km/hour
Time (t) = 5 hour
Thus, distance (s) = ?
We know that,
Distance = Speed × Time
= 15 km/h × 5 h
= 75 km
Thus, distance covered by the car in given time = 15 km Answer
Alternate Method (Unitary method)
As given, the speed of the car = 15 km/hour
This means the car covers a distance of 15 km in 1 hour.
∵ The distance covered by the car in 1 hour = 15 km
∴ The distance covered by the car in 5 hour = 15 km × 5
= 75 km
Thus, distance covered by the car in given time = 75 km Answer
Question (3) A car runs for 20 hour. If the speed of the car is 60 km per hour, the what distance the car will cover in the given time?
Solution
Given, Speed of the car (v) = 60 km/hour
Time (t) = 20 hour
Thus, distance (s) = ?
We know that,
Distance = Speed × Time
= 60 km/h × 20 h
= 1200 km
Thus, distance covered by the car in given time = 1200 km Answer
Alternate Method (Unitary method)
As given, the speed of the car = 60 km/hour
This means the car covers a distance of 60 km in 1 hour.
∵ The distance covered by the car in 1 hour = 60 km
∴ The distance covered by the car in 20 hour = 60 km × 20
= 1200 km
Thus, distance covered by the car in given time = 1200 km Answer
Question (4) A man walks 6 km in 1 hour. If the man walks for 5 hour, the what distance will he covered?
Solution
Given, the man walks 6 km in 1 hour.
We know that speed is the distance covered in unit time.
Thus, speed of the man (v) = 6 km/hour
Time (t) = 5 hour
Thus, distance (s) = ?
We know that,
Distance = Speed × Time
= 6 km/h × 5 h
= 30 km
Thus, distance covered by the man in the given time = 30 km Answer
Alternate Method (Unitary method)
As given, the man covers a distance of 6 km in 1 hour.
∵ The distance covered by the man in 1 hour = 6 km
∴ The distance covered by the man in 5 hour = 6 km × 5
= 30 km
Thus, distance covered by the man in given time = 30 km Answer
Question (5) What distance will be covered by a car at a speed of 45 km/h in 9 hour?
Solution
Given, Speed of the car (v) = 45 km/hour
Time (t) = 9 hour
Thus, distance (s) = ?
We know that,
Distance = Speed × Time
= 45 km/h × 9 h
= 405 km
Thus, distance covered by the car in given time = 405 km Answer
Alternate Method (Unitary method)
As given, the speed of the car = 45 km/hour
This means the car covers a distance of 45 km in 1 hour.
∵ The distance covered by the car in 1 hour = 45 km
∴ The distance covered by the car in 9 hour = 45 km × 9
= 405 km
Thus, distance covered by the car in the given time = 405 km Answer
Question (6) Calculate the distance covered by a bus at a speed of 50 km/h in 5 hour.
Solution
Given, Speed of the bus (v) = 50 km/hour
Time (t) = 5 hour
Thus, distance (s) = ?
We know that,
Distance = Speed × Time
= 50 km/h × 5 h
= 250 km
Thus, distance covered by the bus in given time = 250 km Answer
Alternate Method (Unitary method)
As given, the speed of the bus = 50 km/hour
This means the bus covers a distance of 50 km in 1 hour.
∵ The distance covered by the bus in 1 hour = 50 km
∴ The distance covered by the bus in 5 hour = 50 km × 5
= 250 km
Thus, distance covered by the bus in the given time = 250 km Answer
Question (7) Calculate the distance covered by a bus at a speed of 40 km/h in 15 hour.
Solution
Given, Speed of the bus (v) = 40 km/hour
Time (t) = 15 hour
Thus, distance (s) = ?
We know that,
Distance = Speed × Time
= 40 km/h × 15 h
= 600 km
Thus, distance covered by the bus in given time = 600 km Answer
Alternate Method (Unitary method)
As given, the speed of the bus = 40 km/hour
This means the bus covers a distance of 40 km in 1 hour.
∵ The distance covered by the bus in 1 hour = 40 km
∴ The distance covered by the bus in 15 hour = 40 km × 15
= 600 km
Thus, distance covered by the bus in the given time = 600 km Answer
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