An observer is standing next to the tracks, watching a train approach. The train travels at 30 m/s and blows its whistle at 8,000 Hz as it approaches and then passes by the observer without slowing down. Assuming the speed of sound is 340 m/s, how much of a frequency change did the observer hear?

a) Her acceleration during the slide is -6.67 m/s².

b) She slides 1.03 seconds until she stops.

a) We can find her acceleration during the slide with Newton's second law:

[tex] F = ma [/tex]                        

Where:

F: is the force    

m: is the mass = 92.45 kg

a: is the acceleration =?

The force acting on the baseball player is equal to the friction force ([tex]F_{\mu}[/tex]), and it is negative because it is in the opposite direction to the motion:

[tex] -\mu N = ma [/tex]

[tex] -\mu mg = ma [/tex]

[tex] a = -\mu g [/tex]

Where:

N: is the normal force = mg

μ: is the coefficient of kinetic firction = 0.68

g: is the acceleration due to gravity = 9.81 m/s²

Hence, her acceleration during the slide is:

[tex] a = -0.68*9.81 m/s^{2} = -6.67 m/s^{2} [/tex]

b) We can calculate how long does she slide until she stops with the following kinematic equation:

[tex] v_{f} = v_{0} + at [/tex]

Where:

[tex] v_{f} [/tex]: is the final speed = 0 (when she stops)

[tex] v_{0} [/tex]: is the initial speed = 6.87 m/s

t: is the time =?

Then, the time is:

[tex] t = -\frac{v_{0}}{a} = -\frac{6.87 m/s}{-6.67 m/s^{2}} = 1.03 s [/tex]

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Answer:

value of heat is 18 J

2. step by step

formular w=p(volume1-volume2)

w= 1.0×10^5(0.0006-0.0004)

w= 40 J

Answer:

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.

Explanation:

Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated circuits.

The electrical function of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than nine orders of magnitude. The nominal value of the resistance falls within the manufacturing tolerance, indicated on the component.

Answer:

an element with a small number of valence electrons and a large atomic radius

its not in nurtal or park

Derived quantities depend on.( fundamental)..........physical quantity

Are you from Nepal?

Answer:

Derived quantities depend on two or more physical quantity.

Friction can be defined as a type of force that prevents two smooth surfaces from sliding together on each other. Friction is a strong force that opposes motion when two surfaces come in contact with each other.

The different methods/ways to reduce friction include;

- Application of lubricant to surfaces

- Streamlined bodies; this goes a long way in preventing friction between two bodies.

- Decrease in weight; reducing the amount of weight on a substance can also help to reduce friction

- Applying wheels to objects that move/roll on the ground.

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Answer:

Physical change is a temporary change. A chemical change is a permanent change

examples of physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.

HAVE A GREAT DAY :)

El baloncesto es un deporte muy completo, que puede beneficiar mi vida al mejorar mi salud mediante el ejercicio físico, a la vez que puede mejorar el medio ambiente a través de la protección de espacios abiertos para la práctica de este y otros deportes.

El baloncesto es un deporte inventado en 1891 por James Naismith en Estados Unidos. En el, dos equipos de cinco jugadores y siete suplentes cada uno competirán entre sí. El objetivo del juego es capturar la pelota y lanzarla a través de un aro de hierro - la canasta - y evitar que el oponente haga lo mismo.

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Answer:

given,

load = 400 N

effort = 100 N

load distance = 20 cm

we know that ,

E*Ed = L*Ld

=100 N* Ed = 400N * 20 cm

=100N * Ed = 8000N/cm

= Ed =( 8000N/cm ) / 100N

= Ed = 80 cm

b. soln.

given,

load = 600 N

load distance = 2 m

effort = 300 N

effort distance = ?

we know that ,

= E *Ed = L * Ld

= 300N * Ed = 600N * 2 m

= 300N * Ed = 1200N/m

=Ed =( 1200N/m ) / 300 N

= Ed = 4 m

C. soln.

given,

load = 600 N

load distance =20 cm

effort = 200 N

effort distance = ?

M.A = ?

V.R = ?

Efficiency = ?

we know that ,

= E *Ed = L *Ld

= 200N * Ed = 600 N * 20 cm

=200 N *Ed = 12000 N/cm

=Ed = ( 12000 N/cm) / 200 N

= Ed = 60 cm

Also,

M.A = load / effort

=600 N / 200 N

= 3

V.R = Ed/ Ld

= 60 cm / 20 cm

= 4

efficiency = ( M.A / V.R ) 100 %

= ( 3 / 4 ) 100%

= 75 %

d. soln.

given,

load = 600 N

load distance = 0.5 m

effort distance = 2.5 m

effort = ?

we know that ,

= E * Ed = L * Ld

= E * 2.5 m = 600 N * 0.5 m

= E * 2.5 m = 300 N / m

= E = ( 300 N / m ) / 2.5 m

= E = 120 N

Answer:

(a)Friction

Explanation:

It is due to friction as you are rubbing the glass rod with silk cloth  

as friction occurs when 2 surfaces are rubbed against each other

Therefore it is charging by friction

We know

[tex]\boxed{\sf Momentum=Mass\times Velocity}[/tex]

[tex]\\ \sf\longmapsto Momentum=2000(20)[/tex]

[tex]\\ \sf\longmapsto Momentum=40000kgm/s[/tex]

Answer:

Increase in μk

Explanation:

different ans set

Explanation:

If a coil of wire is placed in a changing magnetic field, a current will be induced in the wire. ... A changing magnetic field through a coil of wire therefore must induce an emf in the coil which in turn causes current to flow.

Due to the flow of the current run, the coil magnetic field is produced. Magnetic fields result in magnetic force.

The electric force between the two charges is directly propotional to the product of the charge and inversly propotional to the square of the distance between them.

A current will be generated in a wire coil if it is put in a changing magnetic field. As a result, a changing magnetic field through a coil of wire must create an emf in the coil, causing the current to flow.

A current is induced in a coil of wire when it is put in a changing magnetic field. Something generates an electric field that drives the charges around the wire, causing the current to flow.

Hence due to the flow of the current in the coil magnetic field is produced.

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Answer:

you didn't post any triangles. Thus, the question could not be answered.

Answer:

The given triangle is a right triangle.

The length of the hypotenuse is 2.52.5 units.

The given angle is 39\degree39° .

The unknown side xx is adjacent to the given angle.

We can therefore use the cosine function to find xx .

Recall the mnemonics CAH.

This means that;

\cos\theta=\frac{Adjacent}{Hypotenuse}cosθ=

Hypotenuse

Adjacent

This implies that,

\cos39\degree=\frac{x}{2.5}cos39°=

2.5

x

We multiply both sides by 2.52.5 to get,

2.5\cos39\degree=x2.5cos39°=x

x=2.5(0.7771)x=2.5(0.7771)

We evaluate to get

x=1.94x=1.94

Therefore the length xx of the side of the triangle is 1.91.9 units to the nearest tenth.

[tex]\boxed{\sf W=Fscos\Theta}[/tex]

[tex]\\ \sf\longmapsto W=150(50)cos 60[/tex]

[tex]\\ \sf\longmapsto W=7500\times \dfrac{1}{2}[/tex]

[tex]\\ \sf\longmapsto W=3750J[/tex]

Answer:

Alkali metals

Explanation:

Elements in this group are highly reactive, soft, lustrous and highly conductive.

An element which is highly conductive, highly reactive, soft, and lustrous is most likely an alkali metal.

Alkali metals are in group 1 of the Periodic table which means that they have only a single valence electron.

This causes them to be soft and highly reactive because:

Examples of alkali electrons include:

In conclusion therefore, alkali metals are highly reactive and soft and so the element described above is most likely an alkali metal.

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Answer:

necessary for the growth, development and repair of all body tissues. it's involved in many body functions, including formation of collagen, absorption of iron, the proper functioning of the immune system, wound healing, and the maintenance of cartilage, bones, and teeth.

Explanation:

Answer:

Vitamin C act as antioxidant which protect our cell from damaging caused by radicals.

We know

[tex]\boxed{\sf F_c=\dfrac{mv^2}{r}}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(10)^2}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(100)}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{2000}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=500N[/tex]

The centripetal force on the truck can be determined from the mass, velocity and the radius of the circular path. The centripetal force acting on the truck is 500 N. Hence, option A is correct.

Centripetal force is a type force acting on an object traveling through a circular path. The centripetal force is the rotational analogue of the linear force.

The centripetal force acting on an object is related to the mass, velocity and radius of the circular path is given by:

Fc =  mv ²/r

Given that, mass of truck = 20 Kg

radius of circle = 4 m

velocity = 10 m/s

Then, centripetal force Fc = 20 kg ×  10² m/s / 4 m = 500 N

Therefore, the centripetal force on the truck is 500 N.

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Answer:

The mass of platinum iridium rod whose diameter and height are equal an kept at international bureau of weight and measurement in Paris of France is called as one standard kg.

Answer:

12000gram

Explanation:

1kg=1000gram

so, 12kg=12x1000

12kg=12000gram

Given amount=12kg

[tex]\boxed{\sf 1kg=1000g}[/tex]

[tex]\\ \sf\longmapsto 12kg=12(1000)[/tex]

[tex]\\ \sf\longmapsto 12kg=12000g[/tex]

Explanation:

A manometer is a device that measures air pressure using a container with a "U"-shaped tube open at one or both ends. In a closed manometer, a sample of gas is introduced into one end, which is then capped. ... This pressure represents the positive or negative difference between the gas pressure and atmospheric pressure

Answer:

2. In addition, the other end of the tube is left open to the atmosphere and it will be subjected to the pressure of approximately 1 atmosphere (atm).

3. Besides, the test pressure is greater than the pressure of 1 atm (atmosphere) the liquid in the column will be forced down by the pressure.

4. Furthermore, it will cause the liquid of the reference column to rise by an equal amount.

Ploughing field with harrow pulled by a tractor being a modern technology​ is true.

This involves the use of scientific knowledge to tackle different life problems and has different sectors.

Ploughing field with harrow pulled by a tractor involves machines and not manual labour which makes it a modern technology.

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Answer:

I = 0.6A

Explanation:

Ohm's Law

V = I*R

I = V/R

I = 120V/200ohms

I = 0.6A

Answer:

Yes, this is true.

-- While the apple is falling, the same gravitational force acts on both the apple and the Earth.

-- The mass of the apple is somewhere in the neighborhood of 1/4 kg.

-- The mass of the Earth is about 5.972 x 10²⁴ kg.

-- Since the Earth has roughly 2.389 x 10²⁶ times as much mass as the apple has, the apple has roughly 2.389 x 10²⁶ greater acceleration than the Earth has, and moves roughly 2.389 x 10²⁶ times as far down as the Earth moves up, before they smack together.

-- That's why you don't notice the Earth's motion.

-- Also, you're standing on the Earth, moving up with it, toward the apple.  Maybe it would be different if you were sitting on the apple, riding it down to the ground, and you were able to notice the motion of the ground coming up to meet you at a speed that's 0.00000000000000000000000000419 of YOUR speed.  

Answer From Gauth Math

Answer:

According to Hook's law, we know,

strain/stress =Constant

Explanation: So, the ratio between stress and strain is always constant.

So, if stress is increased, then strain changes in that way so that this ratio always remains constant.

Answer:

0.75 A ig.Hope it helps:))

Answer:

Normal force

Explanation:

Calculating :-

We know

[tex]\boxed{\sf F_c=\dfrac{mv^2}{r}}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(10)^2}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(100)}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{2000}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=500N[/tex]

Answer:

Explanation:

Important here is to know that due north is a 90 degree angle, due east is a 0 degree angle, and due south is a 270 degree angle. Then we find the x and y components of each part of this journey using the sin and cos of the angles multiplied by each magnitude:

[tex]A_x=100cos90\\A_x=0\\B_x=55cos0\\B_x=55\\C_x=12cos270\\C_x=55[/tex]

Add them all together to get the x component of the resultant vector, V:

[tex]V_x=55[/tex]

Do the same to find the y components of the part of this journey:

[tex]A_y=100sin90\\A_y=100\\B_y=55sin0\\B_y=0\\C_y=12sin270\\C_y=-12[/tex]

Add them together to get the y component of the resultant vector, V:

[tex]V_y=88[/tex]

One thing of import to note is that both of these components are positive, so the resultant angle lies in QI.

We find the final magnitude:

[tex]V_{mag}=\sqrt{55^2+88^2}[/tex] and, rounding to 2 sig dig's as needed:

[tex]V_{mag}=[/tex] 1.0 × 10² m; now for the direction:

[tex]\theta=tan^{-1}(\frac{88}{55})=[/tex] 58°

Answer: option c

Because the height is increasing then decreasing