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):


Animals don't make Their own food. they instead depend on the food made by plants. hence no need for chloroplasts
The angular acceleration of a rotating object is given by

where

is the final angular speed of the object

is its initial angular speed

is the time taken to accelerate
For the wheel in our problem,

,

and

, so its angular acceleration is
More force is needed for more mass. Therefore, if the mass is greater and the force is not enough then the object will less likely accelerate