The magnitude of a vector is the square root of its components squared. When you square a negative number, you will always get a positive number. Its like speed of your car. It will always be positive (or 0) whether you are moving forward or you are in reverse gear or stationary.
Because there's no such thing as "really" moving.
ALL motion is always relative to something.
Here's an example:
You're sitting in a comfy cushy seat, reading a book and listening
to your .mp3 player, and you're getting drowsy. It's so warm and
comfortable, your eyes are getting so heavy, finally the book slips
out of your hand, falls into your lap, and you are fast asleep.
-- Relative to you, the book is not moving at all.
-- Relative to the seat, you are not moving at all.
-- Relative to the wall and the window, the seat is not moving at all.
-- But your seat is in a passenger airliner. Relative to people on the
ground, you are moving past them at almost 500 miles per hour !
-- Relative to the center of the Earth, the people on the ground are moving
in a circle at more than 700 miles per hour.
-- Relative to the center of the Sun, the Earth and everything on it are moving
in a circle at about 66,700 miles per hour !
How fast are they REALLY moving ?
There's no such thing.
It all depends on what reference you're using.
Explanation:
the answer to question one is complete the answer to question to is from negative to positive
height of the ball is given as a function of time
it is given by equation
here in order to find the maximum height we will use the concept of calculus where the maximum value of function will exist when its derivative becomes zero.
so here we can say
now we will put t = 3 in the given equation
So the maximum height will be h = 144 ft.
The main job of the lungs is to bring fresh air into your body when you breathe in and removing waste gases when you breathe out.