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A plane travels 350 km south along a straight path with an average velocity of 125 km/h to the south. The plane has a 30 minute layover, and then travels 220 km south with an average velocity of 115 km/h to the south. What is the average velocity for the trip?. a.120 km/hr to the south. b.110 km/hr to the south. c. 121 km/hr to the south. d. need more information

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olemakpadu
Average Velocity = Total Displacement / Total time

1st part of journey,  350 km at velocity 125 km/h

Time = 350 / 125 = 2.8 hours.

2nd part of journey,  220 km at velocity 115 km/h

Time = 220 / 115 = 1.9 hours


Average Velocity = Total Displacement / Total time

                               = (350 + 220) / (2.8 + 1.9)

                                =   570 / 4.7  ≈ 121.3 km/hr 

Average Velocity ≈ 121 km/hr due south.  

Option C.

Answer:

b) [tex]v = 110 km/h[/tex] Towards South

Explanation:

First plane moves with uniform velocity of 125 km/h towards South

so time taken by the plane to move 350 km is given as

[tex]t_1 = \frac{350}{125}[/tex]

[tex]t_1 = 2.8 hours[/tex]

Now it has a layover time of 30 min

then it moves with uniform velocity of 115 km/h towards South

so time taken by the plane to move 220 km is given as

[tex]t_2 = \frac{220}{115}[/tex]

[tex]t_2 = 1.9 hours[/tex]

Now we have total displacement of the plane is

[tex]d = 220 + 350[/tex]

[tex]d = 570 km[/tex]

total time of the journey is given as

[tex]T = 2.8 + 0.5 + 1.9[/tex]

[tex]T = 5.21 h[/tex]

now average velocity is given as

[tex]v = \frac{d}{T}[/tex]

[tex]v = \frac{570}{5.21}[/tex]

[tex]v = 110 km/h[/tex] Towards South

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