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Nikitich [7]
3 years ago
12

A car travels first 30 km at a uniform speed of 20 km

Physics
1 answer:
masha68 [24]3 years ago
6 0

Answer:

20 = 30 / t1

t1 = 3/2

40 = 30 / t2

t2 = 3/4

average speed = total distance / total time taken

= 30 + 30 / 3/2 + 3/4

= 60 /9/4

= 60 × 4/9

= 26.667

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While sitting in your car by the side of a country road, you see your friend, who happens to have an identical car with an ident
arsen [322]

Answer:

         v_s =7.74\ m/s

Explanation:

given,

Speed of sound = 343 m/s

frequency of horn = 260 Hz

the friend is approaching, the frequency is increased by the Doppler Effect. The frequency is 266 Hz

using formula

         f' = \dfrac{v}{v-v_s}f_0

         266= \dfrac{343}{343 - v_s}(260)

         1.023= \dfrac{343}{343 - v_s}

         343 - v_s = 335.26

         v_s =7.74\ m/s

the speed of friends approaching is equal to v_s =7.74\ m/s

7 0
3 years ago
Sean, whose mass is 60 kg, is riding on a 5.0 kg sled initially traveling at 8.0 m/s. He brakes the sled with a constant force,
alexgriva [62]

Answer:

<h3>130N</h3>

Explanation:

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3 years ago
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denis23 [38]

Answer:

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5 0
3 years ago
Vehicles are designed with both plastic and elastic values to absorb energy forces in a manner that will reduce the direct force
garik1379 [7]
That is true. But you still should to the book given to you to find the right answer
4 0
3 years ago
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