Answer:
Friction is a surface force that opposes relative motion.
Answer:Reflection
Explanation:
The throwing back of a sound wave without absorbing it is called reflection
In acoustic reflection of sound is termed as echo i.e. sound arrived at the listener after a particular delay depending upon the position of barrier to the observer.
The reflection of sound is used in many devices like megaphone, trumpets, etc. It is also used in auditorium such that the ceiling of the auditorium is curved for multiple reflections of sound so that sound can be reached at every corner of the auditorium.
Answer: the most potential energy == 5 kg book, 2 m from the ground= 98 Joules
Explanation:
potential energy = m g h
m = mass
g = acceleration due gravity = 9.8 m/s²
h = distance above ground
1. Pe₁ = 1 kg x 2 m x g = 2 g
2. Pe₂ = 5 kg x 2 m x g = 10 g = 10 kg m x 9,8 m/s² = 98 Joules
3. Pe₃ = 1 kg x 0,5 m x g = 0,5 g
4. Pe₄ = 5 kg x 0.5 m x g = 2,5 g
10 > 2,5 > 2 >0,5
Explanation:
1. The entire span of possible sound waves is called the acoustic spectrum. It is subdivided into infrasonic sounds, audible sounds, and ultrasonic sounds.
2. The difference between a musical note and another note at twice the frequency is called an octave.
3. Sound intensity varies with the inverse square of distance.
