Time, Speed & Distance

Speed :
Speed is the rate of change of distance over time, or the distance traveled by an object divided by the time it took to travel that distance.

• A higher speed means an object is moving faster
• lower speed means it’s moving slower.

Example : If a car travels 100 miles in 2 hours find speed ?
Speed = Distance / Time
= 100 / 2
= 50 mph

Distance :
The total length of the actual path followed by an object is called as distance. OR

The extent or amount of space between two things, points, lines, etc

Distance is measured in units of length like meters, kilometers, miles and other units like feet or inches.

Time :

Time is measured in seconds, minutes and hours.

The following table lists units in common use for speed and their abbreviations:

Example : John can type 960 words in 20 minutes. Calculate his typing speed in:

(a) words per minute,
(b) words per hour

Solutions : Typing speed = 960 / 20
= 48 words per minute

b) words per hour means 1 hour = 60 minute
typing speed = 48 * 60
= 2880 words per hour

Example :
Jane drives at an average speed of 45 mph on a journey of 135 miles. How long does the journey take?
Given data :
Average speed of jane = 45 mph
The distance of jane’s journey = 135 mile  

Here we need to find time taken by Jane to complete the journey

The formula for time with speed and distance is given by

      Time = Distance ÷ Speed  

               = 135 / 45 = 3 hrs  

Time taken by Jane to complete the journey = 3 hrs

Example :
Nikki has to travel a total of 351 miles. She travels the first 216 miles in 4 hours.
(a) Calculate her average speed for the first part of the journey.
(b) If her average speed remains the same, calculate the total time for the complete journey.
Solutions :
(a) To calculate Nikki’s average speed for the first part of the journey, we use the formula:

Given that Nikki travels 216 miles in 4 hours, her average speed for the first part of the journey is:

Average Speed=216 miles / 4 hours
=54 mph

(b) To find the total time for the complete journey if her average speed remains the same, we can use the formula:

Given that the total distance is 351 miles and her average speed is 54 mph, we can calculate the total time:

Total Time= 351 miles / 54 mph ≈ 6.5 hours
So, the total time for the complete journey would be approximately 6.5 hours.

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