The easiest, non-technical way to think about it is like this:
-- A scalar is a quantity that has a size but no direction.
Those include temperature, speed, cost, volume, distance, etc.
One number is all there is to know about it, and there's no way you can
add more of the same stuff to it that would cancel both of them out.
-- A vector is a quantity that has a size and also has a direction.
Those include force, displacement, velocity, acceleration, etc.
It takes more than one number to completely describe one of these.
Also, if you combine two of the same vector quantity in different ways,
you can get different results, and they can even cancel each other out.
Here are some examples. Notice that in each of these examples,
every speed has a direction that goes along with it. This turns the
scalar speed into a vector velocity.
If you're walking inside a bus, and the bus is driving along the road,
then your velocity along the road is the sum of your walking velocity
inside the bus plus the velocity of the bus along the road.
-- If you're walking north up the middle of the bus at 2 miles per hour
and the bus is driving north along the road at 20 miles per hour, then
your velocity along the road is 22 miles per hour north.
-- If you're walking south towards the back of the bus at 2 miles per hour
and the bus is driving north along the road at 5 miles per hour, then your
velocity along the road is 3 miles per hour north.
-- If you're walking south towards the back of the bus at 2 miles per hour
and the bus is just barely rolling north along the road at 2 miles per hour,
then your velocity along the road is zero.
-- If you're in a big railroad flat-car that's rolling north along the track
at 2 miles per hour, and you walk across the flat-car towards the east
at 2 miles per hour, then your velocity along the ground is 2.818 miles
per hour toward the northeast.
Answer:
d = 0 [m]
Explanation:
Displacement is understood as the length and direction that a body travels to move from an initial point to an endpoint.
This displacement is represented with a vector or straight line that indicates the distance of the displacement and its length.
This displacement in an easier way to understand. It is the distance between the start point and the endpoint of the journey. Since the second point is equal to the first point, since Mary returns to the same place, there is no difference between the displacement.
Therefore the displacement is zero.
Answer:
A gravitational force of 6841.905 newtons is exerted on the satellite by the Earth.
Explanation:
At first we assume that Earth is represented by an uniform sphere, such that the man-made satellite rotates in a circular orbit around the planet. Hence, the following condition must be satisfied:
(1)
Where:
- Period of rotation of the satellite, measured in seconds.
- Distance of the satellite with respect to the center of the planet, measured in meters.
- Gravitational constant, measured in newton-square meters per square kilogram.
- Mass of the Earth, measured in kilograms.
Now we clear the distance of the satellite with respect to the center of the planet:
![r = \sqrt[3]{\frac{G\cdot M\cdot T^{2}}{4\pi^{2}} }](https://tex.z-dn.net/?f=r%20%3D%20%5Csqrt%5B3%5D%7B%5Cfrac%7BG%5Ccdot%20M%5Ccdot%20T%5E%7B2%7D%7D%7B4%5Cpi%5E%7B2%7D%7D%20%7D)
(2)
If we know that 
, 
and 
, then the distance of the satellite is:
![r = \sqrt[3]{\frac{\left(6.67\times 10^{-11}\,\frac{N\cdot m^{2}}{kg^{2}} \right)\cdot (6.0\times 10^{24}\,kg)\cdot (25800\,s)^{2}}{4\pi^{2}} }](https://tex.z-dn.net/?f=r%20%3D%20%5Csqrt%5B3%5D%7B%5Cfrac%7B%5Cleft%286.67%5Ctimes%2010%5E%7B-11%7D%5C%2C%5Cfrac%7BN%5Ccdot%20m%5E%7B2%7D%7D%7Bkg%5E%7B2%7D%7D%20%5Cright%29%5Ccdot%20%286.0%5Ctimes%2010%5E%7B24%7D%5C%2Ckg%29%5Ccdot%20%2825800%5C%2Cs%29%5E%7B2%7D%7D%7B4%5Cpi%5E%7B2%7D%7D%20%7D)
The gravitational force exerted on the satellite by the Earth is determined by the Newton's Law of Gravitation:
(3)
Where:
- Mass of the satellite, measured in kilograms.
- Force exerted on the satellite by the Earth, measured in newtons.
If we know that , , 
and , then the gravitational force is:
A gravitational force of 6841.905 newtons is exerted on the satellite by the Earth.
