First you need to make a difference between friction while object is stationary and the friction while object is moving. Force required to start moving some object is slightly greater than force required to maintain objects movement. That means that to move a chair you need some force F1 but you can than slightly reduce force and chair will still be moving.
Now to the problem in this question: It can be said that "stationary friction force" is equal to 15 Newtons. Its also good to know that friction force between chair and floor while you are increasing your push is also increasing and is equal to force of your push. Once it reaches 15N which is it "critical value" for that chair, chair starts moving and friction force drops a little bit and now it is called friction force of moving chair.
Answer:
m = 8
Explanation:
A telescope is a device that allows us to see objects that were very far from us, it is built by the combination of two lenses, the one with the lowest focal length near the eye and that is the one or the one with the greatest focal length, the most eye-flounder . The magnification of the telescope is
m = - f₀ / 
Where f₀ is the focal length of the lens and f_{e} is the false distance of the eyepiece.
It is this problem that gives us the diopter of each lens, these are related to the focal length in meters
D = 1 / f
Let's find the focal length
f₁ = 1 / D₁
f₁ = 1 / 1.16
f₁ = 0.862 m
f₂ = 1 / 9.37
f₂ = 0.1067 m
Therefore, the lens with f₂ is the eyepiece and the slow one with the
distance focal f₁ is the objective.
Let's calculate
m = - f₂ / f₁
m = - 0.862 / 0.1067
m = 8
Answer: D. The object would have an acceleration of 6 m/s/s to the right.
Explanation:
I got it right on USA test prep
Answer: The property that will best provide evidence that the samples are solid includes:
--> if the substance has a definite shape,
-->if the substance has a definite volume
--> if it's tightly packed.
Explanation:
According to the kinetic theory of matter, every substance consist of very large number of very small particles called molecules. These molecules, which are made up of atoms that are the smallest particles of a substance that can exist in a free state.
Matter can exist in the following states:
--> Solid state
--> liquid state or
--> Gaseous state.
The general property of a substance that is in gaseous state includes:
--> Definite shape: A substance can be grouped as a solid if it's shape is fixed that is, it doesn't depend on the shape of other materials.
--> Definite volume: A substance can be grouped as a solid if it occupies its own shape. This is due to the force of cohesion among its molecules.
--> Tightly packed: A substance can be grouped as solid if the molecular movements of the particles are negligible.
From the samples under observation by Juan and kym, if the sample that possesses the above described qualities, it is a solid rather than liquid or gas.
