Answer: Frictional force is when it happens on purpose and normal force is when it happens normal and you are not trying to make it happen on purpose.
Explanation: friction happens on purpose and sometimes you can't control friction but friction is an important thing.
The answer is parallel
If the <span>circuits in a car</span> were series, they would go out at the same time.
I hope this helps! :3
#1
Wavelength = 13 km
it vibrates 10 times each minute
so the frequency is defined by the number of vibrations per second
now the speed of wave is defined as
<em>so here velocity of wave is 2.2 km/s</em>
#2
Intensity of wave is directly proportional to the square of its amplitude
so we can say
k = constant
so if amplitude is doubled then its intensity will be increased by its square
<em>so intensity is 4 times</em>
<span>Molecules at higher temperatures have more energy,
thus they can vibrate faster. Since the molecules vibrate faster, sound
waves can travel more quickly. The speed of sound in room temperature
air is 346 meters per second. so that would be answer A</span>