Answer:
static coefficient = 0,203 & kinetic coefficient = 0,14
Explanation:
There are two (2) conditions, when the desk is about to move and when the desk is moving. In the attachements you can see the two free body diagram for each condition.
In the first condition, there is no movement and the force is 12 N, in the image we can see the total forces are equal to 0 and by the definition of the friction force we can get the static friction coefficient.
In the second condition there is movement in the direction of the force which is equal to 8 N, again by the definition of the friction force we can get the kinetic friction coefficient. Since the desk is moving with constant velocity there is not acceleration.
Answer:
lol imposter winsllllllllllllll
Answer:
The correct answer is a. Both are the same
Explanation:
For this calculation we must use the gravitational attraction equation
F = G m M / r²
Where M will use the mass of the Earth, m the mass of the girl and r is the distance of the girl to the center of the earth that we consider spherical
To better visualize things, let's repair the equation a little
F = m (G M / r²)
The amount in parentheses called acceleration of gravity, entered the force called peos
g = G M / r²
F = W
W = m g
When analyzing this equation we see that the variation in the weight of the girl depends on the distance, which is the radius of the earth plus the height where the girl is
r = Re + h
Re = 6.37 10⁶ m
r² = (Re + h)²
r² = Re² (1 + h / Re)²
Let's replace
W = m (GM / Re²) (1+ h / Re)⁻²
W = m g (1+ h / Re)⁻²
This is the exact expression for weight change with height, but let's look at its values for some reasonable heights h = 6300 m (very high mountain)
h / Re = 10
⁻³
(1+ h / Re)⁻² = 0.999⁻²
Therefore, the negligible weight reduction, therefore, for practical purposes the weight does not change with the height of the mountain on Earth
The correct answer is a
The correct answer of this question is : Artificial luminous sources.
EXPLANATION :
As per the question, we are given some light sources like halogen, laser, sodium-vapor etc.
There are two types of bodies which are known as luminous and non luminous depending on their production of light.
All these sources given in the question are luminous sources as they have their own light. Most importantly they are not natural luminous sources like stars, firefly etc.
All these sources are artificial.
Hence, the correct answer of this question is artificial luminous sources.
