Answer:
I₂ = 0.04 W / m²
Explanation:
Sound intensity is the power emitted between the unit area
I = W / A
W = I A
sound is a wave that travels in space whereby its energy is distributed on the surface of a sphere
A = 4π r²
we substitute
W = I (4π r²)
the emission power is constant, so the intensity at two different points is
W = I₁ 4π r₁² = I₂ 4π r₂²
so the equation is
I₁ r₁² = I₂ r₂²
In this case the units are not shown in the exercise, suppose that all units are in the SI system
I₂ = 
let's calculate
I₂ = 4 
I₂ = 0.04 W / m²
Answer:
The time taken for the race is 17.20 s.
Explanation:
It is given in the problem that a 62.0 kg sprinter starts a race with an acceleration of 1.44 meter per second square.The initial speed of the sprinter is zero as it starts from the rest.
Calculate the final speed of the sprinter.
The expression for the equation of the motion is as follows;
Here, u is the initial speed, v is the final speed, a is the acceleration and s is the distance.
Put u= 0, s=30 m and 
.
Calculate time taken to cover 30 m distance.
The expression for the equation of motion is as follows;
Put u= 0, s=30 m and .
t=6.45 s
Calculate the time taken to complete his race.
T= t+t'
Here, t is the time taken to cover 30 m distance and t' is the time taken to cover 100 m distance.
Put s= 30 m, and s'= 100 m.
T= 17.20 s
Therefore, the time taken for the race is 17.20 s.
Answer:
Homogeneous mixtures may be solids, liquids, or gases. Examples include steel, wine, and air. A homogeneous mixture is a solid, liquid, or gaseous mixture that has a uniform composition. No matter where you sample the mixture, the amount and type of components is the same.
Explanation:
Help of sciencenotes .org
Answer:
The answer is
<h2>56,000 kgm/s</h2>
Explanation:
The momentum of an object can be found by using the formula
<h3>momentum = mass × velocity</h3>
From the question
m = 1400 kg
v = 40 m/s
We have
momentum = 1400 × 40
We have the final answer as
<h3>56,000 kgm/s</h3>
Hope this helps you
Answer:
300 K
Explanation:
First, we have find the specific heat capacity of the unknown substance.
The heat gained by the substance is given by the formula:
H = m*c*(T2 - T1)
Where m = mass of the substance
c = specific heat capacity
T2 = final temperature
T1 = initial temperature
From the question:
H = 200J
m = 4 kg
T1 = 200K
T2 = 240 K
Therefore:
200 = 4 * c * (240 - 200)
200 = 4 * c * 40
200 = 160 * c
c = 200/160
c = 1.25 J/kgK
The heat capacity of the substance is 1.25 J/kgK.
If 300 J of heat is added, the new heat becomes 500 J.
Hence, we need to find the final temperature, T2, when heat is 500 J.
Using the same formula:
500 = 4 * 1.25 * (T2 - 200)
500 = 5 * (T2 - 200)
100 = T2 - 200
=> T2 = 100 + 200 = 300 K
The new final temperature of the unknown substance is 300K.
