Answer:
a. wavelength of the sound, 
b. observed frequecy, 
Given:
speed of sound source, 
= 80 m/s
speed of sound in air or vacuum, 
= 343 m/s
speed of sound observed, 
= 0 m/s
Solution:
From the relation:
v = 
(1)
where
v = velocity of sound
= observed frequency of sound
= wavelength
(a) The wavelength of the sound between source and the listener is given by:
(2)
(b) The observed frequency is given by:
(3)
Using eqn (2) and (3):
C is the answer because it mix and water combining together
Once the car is on top of the hill it contains potential energy witch means it is storing enough energy to slide the hill until acted on. Once the car moves and slides down the hill it creates kinetic energy witch means it's in motion. The car then turns the kinetic energy into mechanical energy witch means it's working. I'm not sure if that helped but good luck!
Answer:
When a negative charge is brought near one end of a conductor electrons are repelled. ... When electric voltage is applied, an electric field within the metal triggers the movement of the electrons, making them shift from one end to another end of the conductor. Electrons will move toward the positive side.
Energy cannot be created nor be destroyed
