High School

Exercise 8.4

1. Convert the following speeds into [tex]m/s[/tex]:
a. [tex]72 \, km/h[/tex]
b. [tex]108 \, km/h[/tex]
c. [tex]900 \, km/h[/tex]

2. Convert the following speeds into [tex]km/h[/tex]:
a. [tex]25 \, m/s[/tex]
b. [tex]45 \, m/s[/tex]
c. [tex]15 \, m/s[/tex]

3. An airplane is flying at a speed of [tex]625 \, km/h[/tex].
a. If the distance between two cities is [tex]1250 \, km[/tex], find the time taken to reach the destination by the airplane.
b. How much distance is covered in 45 minutes?
c. How much distance is covered in 15 seconds?

Answer :

Sure! Let's go through the solution step-by-step:

1. Convert the units of speeds from kilometers per hour (km/h) to meters per second (m/s):

a. For 72 km/h:

72 km/h is equivalent to 20.0 m/s.

b. For 108 km/h:

108 km/h is equivalent to 30.0 m/s.

c. For 900 km/h:

900 km/h is equivalent to 250.0 m/s.

2. Convert the units of speeds from meters per second (m/s) to kilometers per hour (km/h):

a. For 25 m/s:

25 m/s is equivalent to 90.0 km/h.

b. For 45 m/s:

45 m/s is equivalent to 162.0 km/h.

c. For 15 m/s:

15 m/s is equivalent to 54.0 km/h.

3. Determine the time taken by an aeroplane traveling at 625 km/h to cover a distance of 1250 km:

The time taken is 2.0 hours.

4. Calculate the distance covered by the aeroplane in 45 minutes:

In 45 minutes, the aeroplane covers a distance of 468.75 kilometers.

5. Calculate the distance covered by the aeroplane in 15 seconds:

In 15 seconds, the aeroplane covers a distance of approximately 2.604 kilometers.

These are the detailed steps and solutions for converting speeds and calculating time and distance for the aeroplane.