Answer:
(a) 0.115 m
(b) 2.08 x 10^-5 J
Explanation:
mass of bob, m = 81 g = 0.081 kg
The equation of oscillation is given by
θ = 0.068 Cos {9.2 t + Ф}
Now by comparison
The angular velocity
ω = 9.2 rad/s
(a) 
where, L be the length of the pendulum


L = 0.115 m
(b) A = L Sinθ
A = 0.115 x Sin 0.068
A = 7.8 x 10^-3 m
Maximum kinetic energy
K = 0.5 x mω²A²
K = 0.5 x 0.081 x 9.2 x 9.2 x 7.8 x 7.8 x 10^-6
K = 2.08 x 10^-5 J
Answer
Given,
Sound Power, P = 600 W
a) Intensity of sound,
r = 5 m
we know,



I = 1.91 W/m²
b) Sound intensity

I₀ = 10⁻¹²


c) Sound experienced by the Phil
β₁ = 123 - 23 = 100 \ dB
distance from the sound
again using sound intensity formula



where, I = P/A


r = 69.09 m
Distance where Phil will experience same sound intensity without earplug is equal to r = 69.09 m
Explanation:
The force acting between two masses is given by :
........(1)
Where
G is the universal gravitational constant
are masses
d is the distance between two masses
It is clear from equation (1) that the gravitational attraction between the bodies always increases if the masses of bodies increases and when the separation between masses decreases.
So, the correct answer is "the masses increase, and the distance between the centers of mass decreases". This is because the force of gravitation is directly proportional to the masses and inversely proportional to the separation.
The answer is step by step 65