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3 years ago

A sound wave has a frequency of 247 Hz and a wavelength of 1.4 m. What is the speed of the sound wave in air?

1 answer:

5 0

The speed of sound through air at room temperature is almost always 343 m/s. However, since it doesn't tell you that, use the equation wavelength=velocity/frequency. Plug in the numbers: 1.4=v/247, and v=345.8 m/s.

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assuming birdman flies at height of 72m, how fast should he fly to hit bucket at 63m from start of field. gravity is -9.8m/s^2 n

algol [13]

Answer:

.....Birdman?

Explanation:

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3 years ago

What travels faster than anything anything else in the universe?

cluponka [151]

Answer:

The announcement he had made promised to overturn our understanding of the Universe. If the data gathered by 160 scientists working on the project were correct, the unthinkable had been observed. Particles – in this case, neutrinos – had travelled faster than light.

Explanation: Plz Mark brainleist

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2 years ago

What is displacement

saveliy_v [14]

This is what wiki says hope it helps
A displacement is a vector whose length is the shortest distance from the initial to the final position of a point P.[1] It quantifies both the distance and direction of an imaginary motion along a straight line from the initial position to the final position of the point.

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3 years ago

Read 2 more answers

A penny has a mass of 2.50 g, a diameter of 19.55 mm, and a thickness of 1.55 mm. Calculate the density of the material from whi

Dmitry [639]

Density = (mass) divided by (volume)

We know the mass (2.5 g). We need to find the volume.

The penny is a very short cylinder.
The volume of a cylinder is (π · radius² · height).
The penny's radius is 1/2 of its diameter = 9.775 mm.
The 'height' of the cylinder is the penny's thickness = 1.55 mm.

Volume = (π) (9.775 mm)² (1.55 mm)

   = (π) (95.55 mm²) (1.55 mm)

   = (π) (148.1 mm³)

   = 465.3 mm³

We know the volume now. So we could state the density of the penny,
but nobody will understand what we have. Here it is:

   mass/volume = 2.5 g / 465.3 mm³ = 0.0054 g/mm³ .

Nobody every talks about density in units of ' gram/(millimeter)³ ' .
It's always ' gram / (centimeter)³ '.
So we have to convert our number for the volume.

   (0.0054 g/mm³) x (10 mm / cm)³

   = (0.0054 x 1,000) g/cm³

   = 5.37 g/cm³ .

This isn't actually very close to what the US mint says for the density
of a penny, but it's in a much better ball park than 0.0054 was.

4 0

3 years ago

Attempt 2 You have been called to testify as an expert witness in a trial involving a head-on collision. Car A weighs 15151515 l

Natasha_Volkova [10]

Answer:

v = 28.98 ft / s

Explanation:

For this problem we must solve it in parts, let's start by looking for the speed of the two cars after the collision

In the exercise they indicate the weight of each car

Wₐ = 1500 lb

W_b = 1125 lb

Car B's velocity from v_b = 42.0 mph westward, car A travels east

let's find the mass of the vehicles

W = mg

m = W / g

mₐ = Wₐ / g

m_b = W_b / g

mₐ = 1500/32 = 46.875 slug

m_b = 125/32 = 35,156 slug

Let's reduce to the english system

v_b = 42.0 mph (5280 foot / 1 mile) (1h / 3600s) = 61.6 ft / s

We define a system formed by the two vehicles, so that the forces during the crash have been internal and the moment is preserved

we assume the direction to the east (right) positive

initial instant. Before the crash

p₀ = mₐ v₀ₐ - m_b v_{ob}

final instant. Right after the crash

p_f = (mₐ + m_b) v

the moment is preserved

p₀ = p_f

mₐ v₀ₐ - m_b v_{ob} = (mₐ + m_b) v

v = $\frac{ m_a \ v_{oa} - m_b \ v_{ob} }{ m_a +m_b}$

we substitute the values

v = $\frac{ 46.875}{82.03} \ v_{oa} - \frac{35.156}{82.03} \ 61.6$

v = 0.559 v₀ₐ - 26.40 (1)

Now as the two vehicles united we can use the relationship between work and kinetic energy

the total mass is

M = mₐ + m_b

M = 46,875 + 35,156 = 82,031 slug

starting point. Jsto after the crash

K₀ = ½ M v²

final point. When they stop

K_f = 0

The work is

W = - fr x

the negative sign is because the friction forces are always opposite to the displacement

Let's write Newton's second law

Axis y

N-W = 0

N = W

the friction force has the expression

fr = μ N

we substitute

-μ W x = Kf - Ko

-μ W x = 0 - ½ (W / g) v²

v² = 2 μ g x

v = $\sqrt{ 2 \ 0.750 \ 32 \ 17.5}$ Ra (2 0.750 32 17.5

v = 28.98 ft / s

3 0

2 years ago