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
tekilochka [14]
2 years ago
13

What is so fragile that just saying its name breaks it?​

Physics
1 answer:
sertanlavr [38]2 years ago
5 0

Answer: The Sound of Silence.

You might be interested in
What element shares the property of forming ions with a 1+ charge?
Oduvanchick [21]

Answer:

the Group 1A metals such as sodium and potassium form +1 charges,

Explanation:

5 0
3 years ago
Read 2 more answers
Why are objects that fall near earth’s surface rarely in free fall?
Sloan [31]

Answer:

Because of the presence of air resistance

Explanation:

When an object is in free fall, ideally there is only one force acting on it:

- The force of gravity, W = mg, that pushes the object downward (m= mass of the object, g = acceleration of gravity)

However, this is true only in absence of air (so, in a vacuum). When air is present, it exerts a frictional force on the object (called air resistance) with upward direction (opposite to the motion of free fall) and whose magnitude is proportional to the speed of the object.

Therefore, it turns out that as the object falls, its speed increases, and therefore the air resistance acting against it increases too; as a result, the at some point the air resistance becomes equal (in magnitude) to the force of gravity: when this happens, the net acceleration of the object becomes zero, and so the speed of the object does not increase anymore. This speed reached by the object is called terminal velocity.

3 0
3 years ago
A long copper rod of diameter 2.0 cm is initially at a uniform temperature of 100°C. It is now exposed to an air stream at 20°C
Lisa [10]

Answer:

t = 4.0 min

Explanation:

given data:

diameter of rod = 2 cm

T_1 = 100 degree celcius

Air stream temperature =  20 degree celcius

heat transfer coefficient = 200 W/m2. K

WE KNOW THAT

copper thermal conductivity = k = 401 W/m °C

copper specific heat Cp = 385 J/kg.°C

density of copper = 8933 kg/m3

charateristic length is given as Lc

Lc = \frac{V}{A_s}

Lc = \frac{\frac{\pi D^2}{4} L}{\pi DL}

Lc = \frac{D}{4}

Lc = \frac{0.02}{6} = 0.005 m

Biot number is given as Bi = \frac{hLc}{k}

Bi = \frac{200*0.005}{401}

Bi = 0.0025

As Bi is greater than 0.1 therefore lumped system analysis is applicable

so we have

\frac{T(t) - T_∞}{Ti - T_∞} = e^{-bt} ............1

where b is given as

b = \frac{ hA}{\rho Cp V}

b = \frac{ h}{\rho Cp Lc}

b = \frac{200}{8933*385*0.005}

b = 0.01163 s^{-1}

putting value in equation 1

\frac{25-20}{100-20} = e^{-0.01163t}

solving for t we get

t = 4.0 min

6 0
3 years ago
Which describes Einstein’s idea of space and time?
Sholpan [36]
Time and space are both relative
8 0
3 years ago
Read 2 more answers
Evaluate ( 64800 ms ) 2 to three significant figures and express the answer in Si units. Express your answer using three signifi
Sergeu [11.5K]

Answer:

42.0×10² second²

Explanation:

Here, time is given in milisecond

(64800 ms)²

= 4199040000 ms²

The SI unit is seconds

1 second = 1000 milisecond

1\ milisecond=\frac{1}{1000}\ second

\\\Rightarrow 1\ milisecond^2=\left(\frac{1}{1000}\right)^2\ second^2

4199040000\ ms^2=4199040000\times \left(\frac{1}{1000}\right)^2\ second^2=4199.04\ second^2

42.0×10² second²

6 0
3 years ago
Other questions:
  • HELP ASAP
    9·2 answers
  • Where are all stars bornWhat is the brightest star in the night sky? What is its magnitude?
    14·1 answer
  • How did the old view of the solar system look like
    9·1 answer
  • The equation for momentum is p = mv, where p is momentum, m is mass, and v
    11·1 answer
  • Match each statement with the type of contraceptive it describes
    12·1 answer
  • Do substances that heat up quickly have high or low specific heat capacity?
    5·1 answer
  • HELP ASAP!!! What was Johann Dobereiner’s contribution to the development of the periodic table?
    11·2 answers
  • HELP ASAP PLEASE!!! A car starting from rest, accelerates constantly at 8m/s2 for 6s. How far did it travel during this time per
    13·2 answers
  • Scientists today learn about the world by _____. 1. using untested hypotheses to revise theories 2. observing, measuring, testin
    7·1 answer
  • When blocking in football, why does a defending lineman often attempt to get his body under that of his opponent and push forwar
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!