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3 years ago

Sound wave cannot propagate through vacuum.Why?Plz give reason in short....

Physics

1 answer:

Olenka [21]3 years ago

4 0

Answer:

Explanation:

If a perfect vacuum existed in any volume, then no sound would be able to propagate through it, because a sound wave is a pressure wave, and there would be identically zero pressure. Of course, we could get into speculations about “dark energy” or “vacuum energy” supporting pressure waves, but let’s not go there.

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A car with a mass of 600 kg is traveling at a velocity of 10 m/s. How much kinetic energy does it have?

vaieri [72.5K]

Answer:

30000 J = 30 kJ

Explanation:

Kinetic energy is the energy possessed by a moving object solely due to its motion.

You can get the K.E. of an object using the equation,

K.E. = $\frac{1}{2} mv^{2}$

So you get,

K.E. = $\frac{1}{2} 600×10^{2}$

= 30000 J = 30 kJ

3 0

3 years ago

Your answer is CORRECT. Let v⃗ be the vector with initial point (8,1) and terminal point (6,4). Express v⃗ as a linear combinati

Phoenix [80]

Answer:

1) Option E is correct.

vector v = (-2î + 3ĵ)

2) Option C is correct.

The vertical component of vector v = 2

3) Option B is correct.

The vector sum of u and v = (4î - 9ĵ)

4) Option B is correct.

5u - 4v = (-30î - -23ĵ)

5) Option F is correct.

Magnitude of v = √32 units = 4√2 units = 5.66 units

6) Option F is correct.

Unit vector in the same direction as v is

v = (î + 3ĵ)/√10 = [(1/√10), (3/√10)]

Explanation:

1) vector v has initial point (8,1) and terminal point (6,4)

Write vector v as a linear combination of the standard unit vector.

v represented in standard form is given as

Vector v = (final position vector) - (initial position vector) = (6î + 4ĵ) - (8î + ĵ) = (-2î + 3ĵ)

2) v be the vector with initial point (−5,1) and terminal point (5,3). Find the vertical component of this vector.

v represented in standard form is given as

Vector v = (final position vector) - (initial position vector) = (5î + 3ĵ) - (-5î + ĵ)

v = (10î + 2ĵ)

The vertical component is the ĵ-component and it is equal to 2

3) Find the sum of the vectors u =6i −4j and v⃗ =−2i −5j

Vector sum is done on a per component basis

Sum = u + v = (6î - 4ĵ) + (-2î - 5ĵ) = (4î - 9ĵ)

4) Given vectors u⃗ =⟨−2,−3⟩ and v⃗ =⟨5,2⟩; find 5u⃗ −4v⃗

u = (-2î - 3ĵ)

v = (5î + 2ĵ)

5u - 4v = 5(-2î - 3ĵ) - 4(5î + 2ĵ)

= (-10î - 15ĵ) - (20î + 8ĵ)

= (-30î - 23ĵ)

5) Find the magnitude of the vector v = (4i−4j)

Magnitude of a vector is given as

/v/ = √[vₓ² + vᵧ²]

where vₓ and vᵧ are x and y components of the velocity.

/v/ = √[(4²) + (-4)²] = 4√2 units = 5.66 units

6) Given the vector v =⟨1,3⟩; find a unit vector in the same direction as v

Unit vector in the direction of a vector = (vector)/(magnitude of vector)

Vector v = (î + 3ĵ)

Magnitude of vector v = √[1² + 3²] = √10

Unit vector in the same direction as v = (î + 3ĵ)/√10

Hope this Helps!!!

8 0

2 years ago

If a 15 kg mass accelerates at a rate of 4 m/s2, what net force acts on it?

jarptica [38.1K]

<h2>Answer: D 60N</h2>

<h3>Explanation:</h3>

Mass(M)=15 kg

Acceleration(A)=4 m/s2

Force=?

Now,

Force(F)=M×A

F=15×4

F=60N Ans

5 0

3 years ago

A- 1000 m/s2<br> Xi-0m<br> Xf-0.75m<br> Vf-?

sleet_krkn [62]

Answer:

The final velocity of the object is, $v_{f}$ = 27 m/s

Explanation:

Given,

The acceleration of the object, a = 1000 m/s²

The initial displacement of the object, $x_{i}$ = 0 m

The final displacement of the object, $x_{f}$ = 0.75 m

The initial velocity of the object will be, $v_{i}$ = o m/s

The final velocity of the object, $v_{f}$ = ?

The average velocity of the object,

v = ( $x_{f}$ - $x_{i}$ )/ t

= 0.75 / t

The acceleration is given by the relation

a = v / t

1000 m/s² = 0.75 / t²

t² = 7.5 x 10⁻⁴

t = 0.027 s

Using the I equation of motion,

$v_{f}$ = u + at

Substituting the values

$v_{f}$ = 0 + 1000 x 0.027

= 27 m/s

Hence, the final velocity of the object is, $v_{f}$ = 27 m/s

8 0

3 years ago

Choose all the answers that apply.

spin [16.1K]

Answer:

B and C?

Explanation:

3 0

3 years ago

Sound wave cannot propagate through vacuum.Why?Plz give reason in short....​

Sound wave cannot propagate through vacuum.Why?Plz give reason in short....