-- Toss a rock straight up. The kinetic energy you give it
with your hand becomes potential energy as it rises.
Eventually, when its kinetic energy is completely changed
to potential energy, it stops rising.
-- When you're riding your bike and going really fast, you come
to the bottom of a hill. You stop pedaling, and coast up the hill.
As your kinetic energy changes to potential energy, you coast
slower and slower. Eventually, your energy is all potential, and
you stop coasting.
-- A little kid on a swing at the park. The swing is going really fast
at the bottom of the arc, and then it starts rising. As it rises, the
kinetic energy changes into potential energy, more and more as it
swings higher and higher. Eventually it reaches a point where its
energy is all potential; then it stops rising, and begins falling again.
Gravity adds 9.8 m/s to the speed of a falling object every second.
An object dropped from 'rest' (v = 0) reaches the speed of 78.4 m/s after falling for (78.4 / 9.8) = <em>8.0 seconds</em> .
<u>Note:</u>
In order to test this, you'd have to drop the object from a really high cell- tower, building, or helicopter. After falling for 8 seconds and reaching a speed of 78.4 m/s, it has fallen 313.6 meters (1,029 feet) straight down.
The flat roof of the Aon Center . . . the 3rd highest building in Chicago, where I used to work when it was the Amoco Corporation Building . . . is 1,076 feet above the street.
Answer:
6 month interval
Explanation:
The distance to a nearby star in theory is more simple than
one might think! First we must learn about the parallax effect. This is the mechanism our eyes use to perceive things at a distance! When we look at the star from the earth we see it at different angles throughout the earth's movement around the sun similar to how we see when we cover on eye at a time. Modern telescopes and technology can help calculate the angle of the star to the earth with just two measurements (attached photo!) Since we know the distance of the earth from the sun we can use a simple trigonometric function to calculate the distance to the star. The two measurements needed to calculate the angle of the star to the earth caused by parallax (in short angle θ) are shown in the second attached photo.
So using a simple trigonometric function 
we can solve for d which is the distance of the earth to the star:
In the first attached photo a picture where r is the distance to the star and the base of the triangle is the diameter of the earth.
