1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Gwar [14]
3 years ago
10

When the volcano Krakatoa erupted in 1883, it was heard 5000 km away. Which statement about the sound from the volcano is not co

rrect?
a. If such a loud sound were to be made today, an astronaut orbiting in space (a vacuum) at a height of 400 km could hear it.
b. People further from the volcano heard the sound later than people nearer to the volcano.
c. The amplitude of the sound waves would have been smaller further from the volcano.
d. The sound was very loud because a lot of energy was transferred to vibrations of the air.
Physics
1 answer:
lina2011 [118]3 years ago
7 0
Answer a) is incorrect as sound does not travel in a vacuum.
You might be interested in
WILL NAME THE BRAINLIEST! An airplane undergoes the following displacements: It first flies 72 km in a direction of 30° East of
nekit [7.7K]

Answer:

82.1 km

Explanation:

We need to resolve each displacement along two perpendicular directions: the east-west direction (let's label it with x) and the north-south direction (y). Resolving each vector:

A_x = (72) sin 30^{\circ} =36.0 km\\A_y = (72) cos 30^{\circ} = 62.4 km

Vector B is 48 km south, so:

B_x = 0\\B_y = -48

Finally, vector C:

C_x = -(100) cos 30^{\circ} =-86.6 km\\C_y = (100) sin 30^{\circ} = 50.0 km

Now we add the components along each direction:

R_x = A_x + B_x + C_x = 36.0 + 0 +(-86.6)=-50.6 km\\R_y = A_y+B_y+C_y = 62.4+(-48)+50.0=64.6 km

So, the resultant (which is the distance in a straight line between the starting point and the final point of the motion) is

R=\sqrt{R_x^2+R_y^2}=\sqrt{(-50.6)^2+(64.6)^2}=82.1 km

4 0
3 years ago
You observe a plane approaching overhead and assume that its speed is 600 miles per hour. The angle of elevation of the plane is
scZoUnD [109]

Answer:4.34 miles

Explanation:

first  Elevation =19^{\circ}

After 1 minute Elevation changes to 59^{\circ}

Ditsance travelled in 1 minute =600\times \frac{1}{60}=10 mile

Now

tan59=\frac{H}{x}

H=xtan59

tan19=\frac{H}{10+x}

H=\left ( 10+x\right )tan19

Equating H

we get

1.319x=10tan19

x=2.61 miles

H=2.61\times tan59=4.34 miles

4 0
3 years ago
Some lenses are shaped with one flat side and one spherically-shaped side. This shape is designed to focus parallel light rays o
Komok [63]

Answer:

Some lenses are used to focus light to a pre-defined point based on the amount of curvature of their surfaces.

In a piano design convex, some surfaces are flat while others has positive lenses (biconvex)

Explanation:

Solution

These lenses are applied to pay attention to light in a  point pre-defined  based on the amount of curvature of their surfaces.

For that of a plano-convex design, one surface has a positive curve and for biconvex lenses, both surfaces are positively curved while the other  remains flat.

when used practically, plano-convex lenses are most commonly used where the object being imaged is far apart from lens.

7 0
3 years ago
Is the 3 in the molecule a coefficient, subscript, or element? 3H₂O₂
JulijaS [17]
<span>coefficient
       
Let's look at the 3 possibilities and see what they are for </span>3H₂O₂ coefficient - This is used to indicate that multiple molecules are used for the formula. In 3H₂O₂ that indicates that we are talking about 3 molecules of H₂O₂ subscript - This is a small number set in a smaller font and placed low to the elements. It indicates the number of each type of atom in the compound. For the formula 3H₂O₂ there are 2 subscripts. Both of them being the number "2" set small and low just after the letters H and O. Those subscripts indicate that there are 2 hydrogen and 2 oxygen atoms per molecule. element - This is the abbreviation for the elements used in the compound. In <span>3H₂O₂</span> there are 2 different elements. H to indicate hydrogen, and O to indicate oxygen.
3 0
3 years ago
I'm completely lost in physics, the Kinematics and dynamics units.. My exam is coming up.. If a biker travelling at 6.4m/s sees
Alexeev081 [22]
D=rt
when biker A catches biker B, the time they've been riding is the same, so 
t=t, or d/r=d/r
the rates are 6.4 and 4.7, so
d/6.4=d/4.7
biker B is 34m ahead, so 
(d+34)/6.4=d/4.7
multiply both sides by 6.4*4.7:
4.7(d+34)=6.4d
4.7d+=6.4d+159.8
1.7d=159.8
d=94 meters

Another way to think of it is that biker A gains 1.7 meters on B every second (6.4-4.7=1.5), so the time it'll take for him to gain 34 meters is 34/1.7=20 seconds. In that time, biker B travels 4.7*20=94 meters
8 0
3 years ago
Other questions:
  • Substances that protect body cells, including those of the immune system, from damage, are known as _____________.
    9·2 answers
  • Please need help for this one
    12·1 answer
  • PLEASE HELPME!!BRAINLIEST!! The development of new technology requires the evaluation of the overall benefit to cost ratio of th
    10·2 answers
  • Haley is trying to pull an object upward. The below forces are acting on the object.
    11·2 answers
  • Greg is in a bike race. At mile marker four (out of ten), his speed was measured at 13.5 mph. Which best describes the measured
    15·2 answers
  • Which statement best describes metallic bonding?
    10·2 answers
  • Julianna blows air onto the balloon to inflate it what can be known about the atoms of the air
    13·2 answers
  • Consult Multiple-Concept Example 5 in preparation for this problem. The velocity of a diver just before hitting the water is -10
    7·1 answer
  • You are sitting 3 m away from you friend who is watching a cartoon on his phone. How will the sound itensity change if your frie
    6·1 answer
  • Encuentre la presion en la otra seccion estrecha si las velocidades en las secciones son de 0.50m\sy 2m\s
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!