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Alona [7]
2 years ago
9

A police car travels towards a stationary observer at a speed of 15m/s. the siren on the car emits a sound of frequency 250Hz. C

alculate the observer frequency. the speed of sound is 340m/s​
Physics
1 answer:
skelet666 [1.2K]2 years ago
7 0

Observer Frequency = sound frequency x ( speed of sound / speed of sound - speed of car)

= 250 x (340/( 340-15))

= 261.54 Hz

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A horizontal circular wire loop of radius 0.7 m lies in a plane perpendicular to a uniform magnetic field that is pointing down
Maru [420]

Answer:

\epsilon=1.10\ V

Explanation:

It is given that,

Radius of the circular loop, r = 0.7 m

Magnetic field, B = 0.44 T

In 0.14 s the wire is reshaped from a circle into a square, but remains in the same plane.

Area of the circular wire,

A_1=\pi r^2

A_1=\pi (0.7)^2=1.539\ m^2

For the area of square,

The circumference of wire, C=2\pi r=2\pi \times 0.7=4.39\ m

Side of square, l=\dfrac{4.39}{4}=1.09\ m

Area of square, A_2=1.09^2=1.188\ m^2

An emf is induced in the loop due to change in its area. The induced emf is given by :

\epsilon=-B\dfrac{dA}{dt}

\epsilon=-B\dfrac{A_2-A_1}{t}

\epsilon=-0.44\times \dfrac{1.188-1.539}{0.14}  

\epsilon=1.10\ V

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True or False: When looking at kinetic vs. thermodynamic products the kinetic product predominates at low temperature.
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Answer:

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A stone is thrown vertically into the air at an initial velocity of 96 ft/s. On Mars, the height s (in feet) of the stone above
vladimir1956 [14]

Answer:

240 ft

Explanation:

t = Time taken

u = Initial velocity = 96 ft/s

v = Final velocity

s = Displacement

a = Acceleration = 12 m/s² on Mars 32 ft/s² on Earth negative due to upward direction

Mars

s=ut+\frac{1}{2}at^2\\\Rightarrow s=96\times t+\frac{1}{2}\times -12\times t^2\\\Rightarrow s=96t-6t^2\ ft

Earth

s=ut+\frac{1}{2}at^2\\\Rightarrow s=96\times t+\frac{1}{2}\times -32\times t^2\\\Rightarrow s=96t-16t^2\ ft

Differentiating the first equation with respect to time we get

\frac{ds}{dt}=96-12t

Equating with zero

0=96-12t\\\Rightarrow t=\frac{96}{12}=8\ s

Differentiating the second equation with respect to time we get

\frac{ds}{dt}=96-32t

Equating with zero

0=96-32t\\\Rightarrow t=\frac{96}{32}=3\ s

Applying the time taken to the above equations, we get

s=96t-6t^2\ ft\\\Rightarrow s=96\times 8-6\times 8^2\\\Rightarrow s=384

s=96t-16t^2\\\Rightarrow s=96\times 3-16\times 3^2\\\Rightarrow s=144

Difference in height = 384-144 = 240 ft

The stone will travel 240 ft higher on Mars

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2 years ago
A proton moves with a speed of 1.17 105 m/s through Earth's magnetic field, which has a value of 50.0 µT at a particular locatio
vlabodo [156]

a) Southward you need to apply right hand rule. If you close your hand to the east, your thumb will indicate south.

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Given the electric force by,

F_e = 1.6*10^{-19}*1.5*10^2

F_e = 2.4*10^{-17}N

F=9.36*10^{-19}N

7 0
2 years ago
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