WALKING UP A HILL

Walking Up Hill

When you walk up a Hill or a slope, its more slower, even when you apply much effort. Do you know why? Read this.

When you move a distance by walking, you do work; infact, work=forceXdistance cover in the direction of the force.
Now when you go up a hill, you do the works of:
1. Moving a linear distance forward, and
2.Increasing your altitude, upward.

Physics explains it all.

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EARTH YEARS

Did you know?
The earth year can be measured in several ways,

1.Tropical Year(365.242 days):
Gotten from the measurement of the time taken for the earth to round the sun and come back to its former inclination to the sun.

2.Sidereal Year(365.256 days):
Time taken for earth to cross the star rising behind our sun.(Refer to the image below)

3. Anomalistic Year(365.260 days):
Time it takes the earth to make its closest approach to the sun on its elliptical axis.

So far, the most popular is the tropical year which determines weather and climate.

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THE PHYSICS OF SKYDIVING

Skydivers

This is what happens at each stage of skydiving
1.On leaving the plane,
the person starts accelerating on his own weight.
-Force: Downward(the person's weight)
-Acceleration: 9.8m/s2(gravitation)
-Velocity: 0m/s

2....with time
The person accelerates downward on gravity. He will be resisted by air molecules(this is called a Drag); and this occurs till the drag is equal the person's weight. The person eventually stops accelerating and starts travelling at a uniform velocity.
-Force: Downward=Upward(the divers weight) i.e. no resultant forces again
F=0N
-Acceleration:0m/s2 (since a=f/m, f=0)
Velocity: >>0m/s and Constant. This is the highest velocity this diver can travel, and it is known as TERMINAL VELOCITY.

3.Opening the parachute
This increase the drag force on the diver, hence he starts deccelerating.
-Force: Downward<Upward
-Acceleration: negative
-Velocity: Reducing

4...with time
the body deccelerates to a new terminal velocity. The drag reduces again to equal the weight.
-Force:Downward=Upward
-Acceleration:0m/s
-Velocity:Reduced but >0m/s

This new velocity makes it safe for him to land.


Watch the demostration here