Answer:
kinetic friction may be greater than 400 N or smaller than 400 N
Explanation:
As we know that maximum value of static friction on the rough surface is known as limiting friction and the formula of this limiting friction is known as

now when object is sliding on the rough surface then the friction force on that surface is known as kinetic friction and the formula of kinetic friction is known as

now we know that

so here value of limiting static friction force is always more than kinetic friction
also we know that
initially when body is at rest then static friction value will lie from 0 N to maximum limiting friction
and hence kinetic friction may be greater than static friction or if the static friction is maximum limiting friction then kinetic friction is smaller than static friction
so kinetic friction may be greater than 400 N or smaller than 400 N
Mass.
Because mass doesn't depend on weight but weight depends on mass.
A) Rubber stops charges from flowing. This protects people by stopping electricity from flowing.
Explanation:
The statement that best describes the point of wrapping rubber around the copper wire is that the rubber stops charges from flowing. This prevents people from getting electrical shocks by stopping the flow of electricity.
- A rubber is an insulator.
- Insulators are substances that prevents the flow of electricity.
- The lack free mobile electrons or ions that makes them conductors.
- When they are wrapped round a conductor such as copper wire, they will halt the flow of charges.
- Copper is a conductor of both heat and electricity. It has free mobile electrons.
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The frequency of the wave is 
Explanation:
The frequency, the wavelength and the speed of a wave are related by the following equation:

where
c is the speed of the wave
f is the frequency
is the wavelength
For the radio wave in this problem,


Therefore, the frequency is:

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The correct answer for this is A. <span>Accompany her to talk with your parents or another trusted adult to ask for help
when a friend is under the problems of addiction, it's always best to get help from a trusted adult.</span>