This behavior is called reflection.
Reflection is a change of in direction of the wave when it reaches another medium. Imagine a wave colliding with a glass in a tank of water.
During reflection, some of the initial energy of the wave is lost.
Waves always reflect with at same angle at which it approached the obstacle.
Answer:
Pi(3.14) radians or 180º degrees
Explanation:
First of all, we need to obtain the wavelength of a wave traveling to the speed of sound and 420 Hz of frequency.
The formula is:
where l = wavelength in meters
With current values:
l = 336 [m/s]/420[1/s] = 0.8 meters
Since a complete cycle (360º or 2pi radians) needs 0.8 meters to complete, 0.4 meters or 40 cm is just half of it, making a 180º degree phase or 3.14 radians.
Well you know the formula is,
Power= Work/Time
So as time increases, Power Decreases, it's an inverse relationship.
Think about it like this, to have more "power" you have to be able to do a lot in a short amount of time, so by spending more time on something, your power decreases.
Using kinematic equation s=ut + 1/2 at^2(u = initial velocity=0, s=120m, t= 6.32s), 120 = 0(t) + 1/2 a(6.32)^2. a = 120x2/(6.32)^2 = 6m/s^2.
