Answer:
The magnitude of the frictional force is 
Explanation:
From the question we are told that
The force exerted on the box is 
Generally for the box to remain at rest then it means that the frictional force is greater than or equal to the force applied to move it i.e

=> 
The speed of a 16cm wave with a period of 8 seconds is 2cm/s
<h3>How to determine the speed</h3>
Using the formula;
Speed = distance ÷ time
Distance = 16cm
time = 8 seconds
Substitute into the formula
Speed = 16 ÷ 8
Speed = 2 cm/s
Therefore, the speed of a 16cm wave with a period of 8 seconds is 2cm/s
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U need a positive and a negative i will say b cause electron r negative and protons are positive
Yes, that is truly amazing.
They significantly reduced the noise's intensity by 90%, that might be proper reaction.
<h3>What is noise?</h3>
- Unwanted sound that is regarded loud, unpleasant, or disruptive to hearing is called noise.
- Physically speaking, there is no difference between unwanted sound and desired sound because both are vibrations traveling through a medium like air or water.
- When the brain receives and interprets a sound, a difference occurs.
- Decibels are used to measure sound (dB).
- A motorcycle engine operating is roughly 95 dB louder than regular conversation, which is around 60 dB louder than a whisper.
- Your hearing may begin to be harmed if exposed to noise over 70 dB for an extended period of time.
- Your ears can suffer instant damage from loud noise above 120 dB.
<h3>What is sound intensity?</h3>
- The power carried by sound waves per unit area in a direction perpendicular to that region is known as sound intensity or acoustic intensity.
- The watt per square meter is the SI measure of intensity, which also covers sound intensity.
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Answer:
(i) Electric field outside the shell:
For point r>R; draw a spherical gaussian surface of radius r.
Using gauss law, ∮E.ds=q0qend
Since E is perpendicular to gaussian surface, angle betwee E is 0.
Also E being constant, can be taken out of integral.
So, E(4πr2)=q0q
So, E=4πε01r2q