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kow [346]
4 years ago
11

A hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake.

She hears the echo 3.7s\; s after shouting. The speed of sound in air is 343 m/s\rm m/s. Determine the length of the lake. Express your answer to two significant figures and include the appropriate units.
Physics
1 answer:
Nataliya [291]4 years ago
8 0

To solve the exercise it is necessary to take into account the definition of speed as a function of distance and time, and the speed of air in the sound, as well

v=\frac{d}{t}

Where,

V= Velocity

d= distance

t = time

Re-arrange the equation to find the distance we have,

d=vt

Replacing with our values

d= (343)(3.7)

d= 1269.1m

It is understood that the sound comes and goes across the entire lake therefore, the length of the lake is half the distance found, that is

L_{lake} = \frac{d}{2}

L_{lake} = \frac{1269.1}{2}

L_{lake} = 634.55m

Therefore the length of the lake is 634,55m

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The same strength force was exerted in the same direction on both Object A and Object B. Why did Object A go faster than Object
VashaNatasha [74]

Answer:

m_B > m_A

the mass of body B must be greater than the mass of body A

Explanation:

Newton's second law establishes a linear relationship between the force, the mass of the body and its acceleration

        F = m a

        a = F / m

Let's analyze this expression tells us that the force is of equal magnitude for the two bodies, but body A goes faster than body B, this implies that it has more relationships

         a_A > a_B

         \frac{F}{m_A} > \frac{F}{m_B}

         m_B > m_A

Therefore, for this to happen, the mass of body B must be greater than the mass of body A

6 0
3 years ago
Suppose that you are holding a pencil balanced on its point. If you release the pencil and it begins to fall, what will be the a
Naily [24]

Answer:

The angular acceleration of the pencil<em> α  = 17 rad·s⁻²</em>

Explanation:

Using Newton's second angular law or torque to find angular acceleration, we get the following expressions:

    τ = I α                              (1)

    W r = I α                          (2)

The weight is that the pencil has is,

   sin 10 = r / (L/2)

   r = L/2(sin(10))

 

The shape of the pencil can be approximated to be a cylinder that rotates on one end and therefore its moment of inertia will be:

    I = 1/3 M L²

Thus,

   mg(L / 2)sin(10) = (1/3 m L²)(α) 

   α(f) = 3/2(g) / Lsin(10)

   α  = 3/2(9.8) / 0.150sin(10)

  <em> α  = 17 rad·s⁻²</em>

Therefore, the angular acceleration of the pencil<em> </em>is<em> 17 rad·s⁻²</em>

3 0
3 years ago
Which<br> factors will increase the speed of a sound wave in the air?
Dafna11 [192]
A higher temperature, stiffer materials, and less dense materials increase the speed of sound.
7 0
4 years ago
A dart is loaded into a spring-loaded toy dart gun by pushing the spring in by a 
distance d. For the next loading?the spring is
Mrac [35]

Answer:

W'=\dfrac{W}{9}

Explanation:

The potential energy of the spring or the work done by the spring is given by :

W=\dfrac{1}{2}kd^2............(1)

k is the spring constant

d is the compression

When the spring is compressed a distance d' = d/3, let W' is the work is required to load the second dart. Then the work done is given by :

W'=\dfrac{1}{2}kd'^2

W'=\dfrac{1}{2}k(d/3)^2.............(2)

Dividing equation (1) and (2) :

\dfrac{W}{W'}=\dfrac{1/2kd^2}{1/2k(d/3)^2}

\dfrac{W}{W'}=9

W'=\dfrac{W}{9}

So, the work required  to load the second dart compared to that required to load the first is one-Ninth as much. Therefore, the correct option is (E).

7 0
3 years ago
What would the dogs velocity be if ran the same distance in the opposite direction but covered the distance in 24 seconds
iVinArrow [24]

Answer:

I learned this last year but I don't remember. Sorry

7 0
4 years ago
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