<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
Answer:
The maximum height a person's brain could be above his heart is: 1.28 meter.
Explanation:
We need to know what is the normal blood pressure ours hearts so there is a rate: 120/80 (mmHg) and the average will be: 100 (mmHg) and using the Pascal law that relate pressure, density, gravity and height like:
, where P is pressure, p is density, g is the gravity acceleration and h is the height. Now we can find the height and delta of pressure will be: P2-P1 = 100 (mmHg), knowing that 1(mmHg) is equal to 133 Pa, we can do the convertion to 13332.2 (Pa), now because the units of Pascal are Newton/(meter^2). Then we solve the formula to get the height:
so we get:
Any gas in the atmosphere that absorbs and emits thermal infrared radiation is referred to as a greenhouse gas (GHG). These are the primary causes of the greenhouse effect, which causes the Earth's temperature to rise. Earth is warmer because less heat radiates into space.
Answer:
Explanation:
velocity of ship with respect to water = 6.5 m/s due north

velocity of water with respect to earth = 1.5 m/s at 40° north of east

velocity of ship with respect to water = velocity of ship with respect to earth - velocity of water with respect to earth



The magnitude of the velocity of ship relative to earth is
= 5.66 m/s
Answer:
a.
b. 
Explanation:
<u>Given:</u>
- Velocity of the particle, v(t) = 3 cos(mt) = 3 cos (0.5t) .
<h2>
(a):</h2>
The acceleration of the particle at a time is defined as the rate of change of velocity of the particle at that time.

At time t = 3 seconds,

<u>Note</u>:<em> The arguments of the sine is calculated in unit of radian and not in degree.</em>
<h2>
(b):</h2>
The velocity of the particle at some is defined as the rate of change of the position of the particle.

For the time interval of 2 seconds,

The term of the left is the displacement of the particle in time interval of 2 seconds, therefore,

It is the displacement of the particle in 2 seconds.