Respuesta :
Answer:
(a). The average speed less than 25.0 m/s.
(b). The car's average speed is 24 m/s.
Explanation:
Given that,
Speed v= 20.0 m/s
Distance d= 12.0 miles
Speed v'= 30.0 m/s
Distance d'=12.0 miles
We need to calculate the time for first 12 miles distance
Using formula of time
[tex]v=\dfrac{d}{t}[/tex]
[tex]t = \dfrac{d}{v}[/tex]
[tex]t=\dfrac{12.0}{20.0}[/tex]
[tex]t=0.6\ sec[/tex]
We need to calculate the time for another 12 miles distance
Using formula of time
[tex]t=\dfrac{12.0}{30.0}[/tex]
[tex]t=0.4\ sec[/tex]
We need to calculate the average speed
[tex]v_{avg}=\dfrac{D}{T}[/tex]
Where, D = total distance
T = total time
Put the value into the formula
[tex]v_{avg}=\dfrac{12.0+12.0}{0.6+0.4}[/tex]
[tex]v_{avg}=\dfrac{24.0}{1.0}[/tex]
[tex]v_{avg}=24\ m/s[/tex]
The average speed less than 25.0 m/s.
(b). The car's average speed is 24 m/s.
Hence, This is the required solution.
