<h2>The intensity of siren is 0.015 W m⁻²</h2>
Explanation:
The intensity of sound is inversely proportional to the square of distance between source and the observer .
Thus Intensity at a distance 25 m is I₁ ∝
I
Similarly the intensity at a distance 50 m is I₂ ∝
II
Dividing II by I , we have
=
=
= 
Thus I₂ =
x 0.06 = 0.015 W m⁻²
If the mass of both of the objects is doubled, then the force of gravity between them is quadrupled; and so on. Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces.
215
I am assuming that those are the width and length. So to find area all you have to do is multiply the two because lw = a. 12 1/2*17 1/5 = 215
25/2*86/5 = 2150/10 = 215
Answer:

Explanation:
m = Mass of person = 70 kg
c = Specific heat of human body = 
= Change in temperature
Time taken is 1 hour
Heat is given by

The rise in temperature is 
Answer:
200 km/hr
Explanation:
Since he goes 80km per hour, multiply this by 2.5 or two and a half hours.
80 x 2.5 = 200 km/hr.