The answer to your question is "A. a lower frequency of the siren.
Because the person in back of the ambulance will hear a lower frequency of the siren. This is because the waves are stretched out. A longer wavelength results in a lower frequency.
Answer:
4.96 × 10⁵ Pa
Explanation:
F = mg

This force is evenly distributed on the three leg
radius, r = d/2
= 2.8 / 2
= 1.4 cm = 0.014 m
total cross sectional area of the three legs, A = 3*pi*r^2

Pressure due to weight,
P = Weight/A

P = 4.96 × 10⁵ Pa
Pounds
If you are talking about the unit of measurement for weight is that of force it would be Newtons.