A person travels from New York to Washington at the rate of 45 km per hour and
comes backs to the New York at the rate of 55 km per hour. What is his average
speed for the whole journey?

The average speed for the whole journey is 49.5 miles per hour.

Explanation:

Step 1 :

Here, both the ways, he covers the same distance.  Then, the formula to find average speed is

=  2xy / (x+y)

Step 2 :

x > Rate at which he travels from New York to Washington  

x  =  45

y > Rate at which he travels from New York to Washington  

y  =  55

Step 3 :

So, the average speed is

=  (2 ⋅ 45 ⋅ 55) / (45 + 55)

=  4950 / 100

=  49.5

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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