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3 years ago

5

A string of length L is under tension, and the speed of a wave in the string is v. What will be the speed of a wave in the strin

g if the length is increased to 2L but with no change in the mass or tension

1 answer:

lawyer [7]3 years ago

3 0

Answer:

The speed increases by square root 2 times.

Explanation:

Let the wave velocity initially be 'v' with tension in the string as 'T' of mass 'm'.

Given:

Initial length of the string (L₁) = L

Final length of the string (L₂) = 2L

Wave velocity in a stretched string of length 'L' is given as:

$v=\sqrt{\frac{LT}{m}}$

From the above equation we can conclude that if tension 'T' and mass 'm' remains the same, the wave velocity is directly proportional to the square root of length of the stretched string. Therefore,

$v=k\sqrt L\\\\\frac{v_1}{\sqrt{L_1}}=\frac{v_2}{\sqrt{L_2}}$

Now, plug in the given values and solve for v₂ in terms of v₁. This gives,

$v_2=\frac{v}{\sqrt{L}}\times \sqrt{2L}\\\\v_2=\sqrt2 v$

Therefore, the speed of the wave is increased by square root 2 times.

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A student made the following observations about a squirrel’s movements:

dalvyx [7]

The correct option is <u>D</u>.

Qualitative observations are observations that are made using our senses of sight, hearing, smell, taste and feel. These observations do not involve numbers or measurements of any kind.

The student's observations regarding the squirrel as is mentioned in options A, B and C involve measurements. Therefore these are not qualitative observations.

Option D, however, is made on the basis of sight, where the student observes the squirrel moving in a zigzag manner.

Therefore, of all the three observations, the student's observation that the squirrel ran in a zigzag pattern is the qualitative observation.

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3 years ago

What happens to the density of a fluid as the substance gains thernal energy

Natalka [10]

Density reduces

Explanation:

The density of a fluid will reduce as a substance gains more thermal energy. Heat is a form of thermal energy usually noticed as temperature differences in a matter.

When thermal energy is gained by a body, the temperature of the body rises.
The particles of the medium gains more kinetic energy.
This causes the substance to expand and it has more volume.
When a substance expands, it occupies more space.
The more the volume a body occupies, the lesser the density.
Expansion does not change the mass of the fluid but the volume changes.
This is why density decreases.

Learn more:

Density brainly.com/question/8441651

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8 0

4 years ago

If the coefficient of kinetic friction between a 22 kg kg crate and the floor is 0.27, what horizontal force is required to move

alina1380 [7]

Answer:

58.27 N

Explanation:

the data we have is:

mass: $m=22kg$

coefficient of friction: $\mu =0.27$

and we also know the acceleration of gravity is $g=9.81m/s^2$

We need to do an analysis of horizontal and vertical forces acting on the object:

-------

Vertically the forces acting on the object:

Normal force $N$ (acting up from the object)

weight: $w=mg$ (acting down from)

so the sum of forces in the vertical axis "y" are:

$F_{y}=N-w\\F_{y}=N-mg$

from Newton's second Law we know that $F=ma$ , so:

$ma_{y}=N-mg$

and since the object is not accelerating in the vertical direction (the movement is only horizontal) $a_{y}=0$ , and:

$0=N-mg\\N=mg$

-----------

now let's analyze the horizontal forces

frictional force: $f= \mu N$ and since $N=mg$ --> $f=\mu mg$

force to move the object: $F$

and the two forces just mentioned must be opposite, thus the sum of forces in the "x" axis is:

$F=ma_{x}=F-f\\ma_{x}=F-\mu mg$

and we are told that the crate moves at a steady speed, thus there is no acceleration: $a_{x}=0$

and we get:

$0=F-\mu mg\\F=\mu mg$

substituting known values:

$F=(0.27)(22kg)(9.81m/s^2)\\F=58.27N$

3 0

3 years ago

A washing machine heats 10kg of water in each wash cycle. How much energy is saved by washing at 30'c instead of 50'c if the sta

Volgvan

The equation for this is very simple you add then you subtract then you get the answer then you divide then it all works out for you

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4 years ago

Estimate frequency of vibration of your arm. Let the length of the arm be 0.57 m. Consider the arm as a simple pendulum and assu

skad [1K]

Answer:

0.80865 Hz

1.23662 seconds

Explanation:

g = Acceleration due to gravity = 9.81 m/s²

l = Length of arm = 0.57 m

Length of simple pendulum is given by

$L=\dfrac{2}{3}l\\\Rightarrow L=\dfrac{2}{3}\times 0.57\\\Rightarrow L=0.38\ m$

The frequency is given by

$f=\dfrac{1}{2\pi}\sqrt{\dfrac{g}{L}}\\\Rightarrow f=\dfrac{1}{2\pi}\sqrt{\dfrac{9.81}{0.38}}\\\Rightarrow f=0.80865\ Hz$

The frequency is 0.80865 Hz

The time period is given by

$T=\dfrac{1}{f}\\\Rightarrow T=\dfrac{1}{0.80865}\\\Rightarrow T=1.23662\ s$

The time period is 1.23662 seconds

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3 years ago