Answer: 
At sea level, there is one standard atmospheric pressure which is equal to 101.325 kilopascals.
The pressure of faintest sound that a human ear can hear is 20 micro-pascals.
taking the ratio of two:


Hence, the atmospheric pressure at sea level is
times greater than the faintest sound that a human ear can hear.
I think it’s D...not sure tho !
Mass of the block = 1.4 kg
Weight of the block = mg = 1.4 × 9.8 = 13.72 N
Normal force from the surface (N) = 13.72 N
Acceleration = 1.25 m/s^2
Let the coefficient of kinetic friction be μ
Friction force = μN
F(net) = ma
μmg = ma
μg = a
μ = 
μ = 
μ = 0.1275
Hence, the coefficient of kinetic friction is: μ = 0.1275
I believe the answer is D. <span>The hypothesis is revised and another experiment is conducted.</span>
Answer:
<em>The final speed of the vehicle is 36 m/s</em>
Explanation:
<u>Uniform Acceleration</u>
When an object changes its velocity at the same rate, the acceleration is constant.
The relation between the initial and final speeds is:

Where:
vf = Final speed
vo = Initial speed
a = Constant acceleration
t = Elapsed time
The vehicle starts from rest (vo=0) and accelerates at a=4.5 m/s2 for t=8 seconds. The final speed is:


The final speed of the vehicle is 36 m/s