Answer:
a
b
Explanation:
From the question we are told that
The mass of the rock is 
The length of the small object from the rock is 
The length of the small object from the branch 
An image representing this lever set-up is shown on the first uploaded image
Here the small object acts as a fulcrum
The force exerted by the weight of the rock is mathematically evaluated as
substituting values
So at equilibrium the sum of the moment about the fulcrum is mathematically represented as
Here 
is very small so 
and 
Hence
=> 
substituting values
The mechanical advantage is mathematically evaluated as
substituting values
Well, 0.1 is actually less than 0.7, but I understand what you're asking.
The coefficient of friction describes the relationship between two surfaces
that are sliding by each other. The higher the coefficient of friction is, the
'rougher' the meeting is, and the harder it is for one to slide over the other.
A skate blade against ice has a very low coefficient of friction. Sandpaper
against blue jeans has a high coefficient of friction.
A higher coefficient of friction means that when one thing is sliding over
the other one, friction robs more energy from the motion. It's harder to
push one thing over the other one, and when you let go, the moving one
slows down and stops sooner.
Air resistance is actually an example of friction. It prevents falling things
from falling as fast as they would if there were no air. The coefficient of
friction when something moves through air is pretty low. If the same
object were trying to move through molasses or honey, the coefficient
of friction would be greater.
Friction robs energy, and turns it into heat. So, especially in machinery with
moving parts, we want to make the coefficient of friction between the moving parts
as small as possible. That's what the OIL in a car's engine is for.
Answer:
Explanation:
Expression for emf induced = 1 /2 B n r²ω where B is magnetic field , r is radius of the coil and ω is angular velocity of rotation , n is no of turn .
ω = 2πf = 2π x 60 = 120 π ; where f is frequency of rotation .
emf induced = 1 /2 B r²x 120π x n
Putting the given values
10000 = .5 x B x .11² x 120 x 3.14 x 506
B = 8.67 T .
<span>Kinesics
is the study of the interpretation body motion communication such as facial
expressions and gestures. It does not include the verbal communication
because you can communicate through words. Kinesics is a nonverbal
communication that does not involve words. Example of this is when you are in a
different country in which you do not know how to speak their native language. To
understand their feelings, you don’t listen to their words but you observe
their actions and facial structure when communicating. So the answer is letter
A.</span>
