Answer:
495.5 Joules
Explanation:
Given data
Mass= 10kg
Height= 5meters
g= 9.81m/s^2
Yes the rock will possess potential energy before it hits the ground
The potential energy is expressed as
PE=mgh
substitute
PE= 10*9.91*5
PE= 495.5 Joules
Answer:
(C) The frequency decrease and intensity decrease
Explanation:
The Doppler effect describes the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source, or the wave source is moving relative to the observer, or both.
if the observer and the source move away from each other as is the case for this problem, the wavelength heard by the observer is bigger.
The frequency is the inverse from the wavelength, so the frequency heard will increase.
The sound intensity depends inversely on the area in which the sound propagates. When the buzzer is close, the area is from a small sphere, but as the buzzer moves further away, the wave area will be from a larger sphere and therefore the intensity will decrease.
