Answer:
There are three types of material as per the condition of charge flow
1) Conductor
2) Insulator
3) Semiconductor
1) Conductors
As we know that conductors are those which offer very small resistance to the flow of charge
Resistivity of the conductors are very small
2) Insulators
These type of materials offer large resistance to the flow of charges and it will not pass the current through it
So resistivity of the insulators are large as compared to conductors
The time after being ejected is the boulder moving at a speed 20.7 m/s upward is 2.0204 s.
<h3>What is the time after being ejected is the boulder moving at a speed 20.7 m/s upward?</h3>
The motion of the boulder is a uniformly accelerated motion, with constant acceleration
a = g = -9.8 
downward (acceleration due to gravity).
By using Suvat equation:
v = u + at
where: v is the velocity at time t
u = 40.0 m/s is the initial velocity
a = g = -9.8
is the acceleration
To find the time t at which the velocity is v = 20.7 m/s
Therefore,

The time after being ejected is the boulder moving at a speed 20.7 m/s upward is 2.0204 s.
The complete question is:
A large boulder is ejected vertically upward from a volcano with an initial speed of 40.0 m/s. Ignore air resistance. At what time after being ejected is the boulder moving at 20.7 m/s upward?
To learn more about uniformly accelerated motion refer to:
brainly.com/question/14669575
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Answer:
<em> think 2 also if not im so sorry but i think it is :)</em>
Answer:
The area of the portion of the windshield cleaned by the 7-in wiper blade is 62.49 in²
Explanation:
Given
Length of blade = 9 inches
Angle of rotation = 93°
We're to calculate the area of the portion of the windshield cleaned by the 7-in wiper blade?
We'll solve this by using area of a sector.
Area of a sector = ½r²θ
where θ is in radians.
So, angle of rotation (93°) must first be converted to radians
Converting 93º to radians, we get 31π/60
The area of the region swept out by the wiper blade = (area of the sector where r = 9 and
θ = 31π/60) - (area of the sector where r = (9-7) and θ = 31π/60).
We're making use of 9-7 because that region is outside the boundary of the 7in blade
So Area = ½*9²*31π/60 - ½*2²*31π/60
Area = ½*31π/60(9²-7²)
Area = 31π/120 * (81 - 49)
Area = 31π/120 * 32
Area = 992π/120
Area = 62.49151386765697 in²
Area ≈ 62.49 in²
Hence, the area of the portion of the windshield cleaned by the 7-in wiper blade is 62.49 in²