Answer:
Rate of change of area will be 
Explanation:
We have given rate of change of radius 
Radius of the circular plate r = 52 cm
Area is given by 
So 
Puting the value of r and 

So rate of change of area will be 
Exert force upward.
Like when you pick something up from the floor, or walk up the stairs.
Find Acceleration




Now
Using 1st equation of kinematics





Answer:
f = 2858.33 Hz
Explanation:
given,
distance between speaker (A) and the person = 2.34 m
Distance between speaker (B) and the person is AB =
=
= 2.46 m
path difference d = BP - AP
= 2.46 - 2.34 m
= 0.12 m
now, λ = 0.12
speed of sound = 343 m/s


f = 2858.33 Hz
the lowest frequency that will produce constructive interference is equal to
f = 2858.33 Hz