A supernova is a large explosion that takes place at the end of a star's life cycle. Although supernovas only burn for a short amount of time, they can tell scientists a lot about the universe. Scientists use electromagnetic waves to detect supernovas. Why are electromagnetic waves used instead of sound waves?
A. Electromagnetic waves are created by physical vibrations.
B. Electromagnetic waves travel slower than sound waves.
C. Electromagnetic waves can travel in vacuums.
D. Electromagnetic waves cannot be absorbed.

Answer:

D_y = 414.38m

Explanation:

D_y = D*sin(x)

D_y = 673m*sin(38°)

D_y = 414.38m

This question is incomplete, the missing diagram is uploaded along this answer below.

Answer:

- the magnitude of the tension force exerted by the hamstring muscles on the leg is 990 N

- the magnitude of compression force at the knee joint is 900 N

Explanation:

Given the data in the question and diagram below;

Net torque = 0

Torque = force × lever arm

so

F[tex]_{ConF[/tex]  × ( 15.0 in + 1.5 in ) = T[tex]_{HonL[/tex] × 1.5 in

given that F[tex]_{ConF[/tex] = 90 N

90 × ( 15.0 in + 1.5 in ) = T[tex]_{HonL[/tex] × 1.5 in

90 N × 16.5 in =  T[tex]_{HonL[/tex] × 1.5 in

T[tex]_{HonL[/tex] = ( 90 N × 16.5 in ) / 1.5 in

T[tex]_{HonL[/tex] = 990 N

Therefore, the magnitude of the tension force exerted by the hamstring muscles on the leg is 990 N

b) magnitude of compression force at the knee joint;

In equilibrium, net force = 0

along horizontal

F[tex]_{FonB[/tex] - T[tex]_{HonL[/tex] + F[tex]_{ConF[/tex] = 0

we substitute

F[tex]_{FonB[/tex] - 990 + 90 = 0

F[tex]_{FonB[/tex] - 900 = 0

F[tex]_{FonB[/tex] = 900 N

Therefore, the magnitude of compression force at the knee joint is 900 N

Answer:

d. correctly described by all the statements above.

Explanation:

Kinetic molecular theory of gases states that gas particles exhibit a perfectly elastic collision and are constantly in motion.

According to the kinetic-molecular theory, the average kinetic energy of gas particles depends on temperature.

This ultimately implies that, the average kinetic energy of gas particles is directly proportional to the absolute temperature of an ideal gas. Thus, an increase in the average kinetic energy of gas particles would cause an increase in the absolute temperature of an ideal gas.

Temperature can be defined as a measure of the degree of coldness or hotness of a physical object. It is measured with a thermometer and its units are Celsius (°C), Kelvin (K) and Fahrenheit (°F).

Generally, the temperature of a quantity of an ideal gas is;

a. a measure of the ability of an ideal gas to transfer thermal energy to another body.

b. the average kinetic energy of gas particles is directly proportional to the absolute temperature of an ideal gas

c. proportional to the internal energy of the gas.

Answer:

Refer to the attachment!~

Answer:

Alleles AA and aa

Explanation:

For all the offsprings of the butterflies to have the same heterozygous alleles Aa, it means the two parents have different homogyzous alleles. That is, one of the parents had the alleles AA while the other had the alleles aa. Thus, a combination of the two pairs of alleles will produce 100% Aa alleles in the offspring as seen in the image attached.

Answer:

a)   L = 4.75 103 kg m² / s,  b)  K_total = 2.57 10³ J,  

c)   L₀ = L_f =4.75 103 kg m² / s,  d)  K = 1.03 10⁴ J,  K = 1.03 10⁴ J

Explanation:

a) the angular momentum is the sum of the angular momentum of each astronaut

the distance is measured from the center of the circle r = 10/2 = 5.0 m

            L = 2m v r

            L = 2  88.0 5.40 5.0

            L = 4.75 103 kg m² / s

b) rotational kinetic energy

            K = ½ I w²

As there are two astronauts, the total energy is the sum of the energy of each no.

The moment of inertia of a point mass

             I = m r²

             I = 88 5²

             I = 2.2 10³ kg m²

the angular velocity is given by

             v = w r

             w = v / r

             w = 5.40 / 5

             w = 1.08 rad / s

the kinetic energy of the system

             K_total = 2 K

             K_total = 2 (½ I w²)

             K_total = 2.2 10³ 1.08²

             K_total = 2.57 10³ J

c, d) as astronauts are isolated in space, these speeds do not change unless there is an interaction between them, for example they approach each other, suppose they reduce their distance by half

             r = 2.5 m

             I = 88 2.5²

             I = 5.5 10² kg m²

for the change in angular velocity let us use the conservation of moment

            L₀ = L_f

            2Io wo = 2 I w

            w = Io / I wo

            w = 2.2 10³ / 5.5 10² 1.08

            w = 4.32 rad / s

linear velocity is

            v = w r

            v = 4.32 2.5

             K = 1.03 10⁴ J

the kinetic energy of the system is

            K = 5.5 10² 4.32²

            K = 1.03 10⁴ J

Answer:

A

Explanation:

I guess not that much confidential!

RQ/PQ I think

rise/run

Answer:

Average speed = total distance traveled / total time traveled

V = (2 + 80) / (2 + 40) = 82 / 42 = 2 m / s

Answer:

Gamma rays

Explanation:

Gamma rays have the highest frequency in the electro magnetic spectrum

Answer:

a = ?

u = 0

v = 30

by using v = u + at equation we can find " a "

30 = 0 + 5a

6 m/s = a

by using f = ma equation we can find force produce by engine ,

f = ?

a = 6

m = 1200

f = 1200 × 6

f = 7200 N

so the answer is "B"

Answer:

Explanation:

Here's what we know and in which dimension:

y dimension:

[tex]v_0=30[/tex] m/s

v = 0 (I'll get to that injust a second)

a = -9.8 m/s/s

The final velocity of 0 is important because that's the velocity of the ball right at the very top of its travels. If we knew how long it takes to get to that max height, we can also use that to find out how long it will take to hit the ground. Therefore, we will find the time it takes to reach its max height and pick up with the investigation of what this means after.

x dimension:

Δx = 70 m

v = ??

Velocity is our unknown.

Solving for the time in the y dimension:

[tex]v=v_0+at[/tex] and filling in:

0 = 30 + (-9.8)t and

-30 = -9.8t so

t = 3.1 seconds

We know it takes 3.1 seconds to get to its max height. In order to determine how long it will take to hit the ground, just double the time. Therefore, it will take 6.2 seconds for the ball to come back to the ground, which is where the persom trying to catch the ball comes in. We will use that time in our x dimension now.

In the x dimension, the equation we need is just a glorified d = rt equation since the acceleration in this dimension is 0.

Δx = vt and

70 = v(6.2) so

v = 11.3 m/s

Answer:

S = 1/2 gt² = 1/2 × 9.8 × 3² = 4.9×9 = 44.1 m

Explanation:

Answer:

559.5 N

Explanation:

Applying,

v² = u²+2gs............. Equation 1

Where v = final velocity,

From the question,

Given: s = 5.10 m, u = 0 m/s ( from rest)

Constant: 9.8 m/s²

Therefore,

v² = 0²+2×9.8×5.1

v² = 99.96

v = √(99.96)

v = 9.99 m/s

As the diver eneters the water,

u = 9.99 m/s, v = 0 m/s

Given: t = 1.34 s

Apply

a = (v-u)/t

a = 9.99/1.34

a = -7.46 m/s²

F = ma.............. Equation 2

Where F = force, m = mass

Given: m = 75 kg, a = -7.46 m/s²,

F = 75(-7.46)

F = -559.5 N

Hence the average force exerted on the diver is 559.5 N

Answer:

- the power to the air is 850 MW

- mass flow rate of the air is 84577.11 kg/s

Explanation:

Given the data in the question;

Net power generated; [tex]W_{net[/tex] = 150 MW

Heat input; [tex]Q_k[/tex] = 1000 MW

Power to air = ?

For closed cycles

Power to air Q₀ = Heat input; [tex]Q_k[/tex] - Net power generated; [tex]W_{net[/tex]

we substitute

Power to air Q₀  = 1000 - 150

Q₀ = 850 MW

Therefore,  the power to the air is 850 MW

given that ΔT = 10 °C

mass flow rate of air required will be;

⇒ Q₀ / CpΔT

we know that specific heat of air at p=c ; Cp = 1.005 kJ/kg.K

we substitute

⇒ ( 850 × 10³ ) / [ 1.005 × 10 ]

⇒ ( 850 × 10³ ) / 10.05

⇒ 84577.11 kg/s

Therefore, mass flow rate of the air is 84577.11 kg/s

xin lỗi không có sơ đồ vui lòng cho biết sơ đồ



The boy pushed the sled for 16 seconds.

We have a boy who pushes his little brother on a sled.

We have to determine for how long time does boy push the sled.

The Work - Energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle.

According to the question -

The sled is initially at rest → initial velocity (u) = 0.

Final velocity (v) = 4 m/s

Mass of boy and sled (M) = 40 kg

Power developed (P) = 20 W = 20 Joules/sec

According to work - energy theorem -

Work done (W) = Δ E(K) = E(f) - E(i)

Therefore -

W = ([tex]\frac{1}{2} \times 40 \times 4 \times 4 - \frac{1}{2}[/tex] x 40 x 0) = 320 Joule

Now, Power is defined as the rate of doing work -

P = [tex]\frac{dW}{dt}[/tex] = [tex]\frac{W}{t}[/tex]

20 = [tex]\frac{320}{t}[/tex]

t = 16 seconds

Hence, the boy pushed the sled for 16 seconds.

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Answer:

the weight of an object is the same on earth and moon

Explanation:

bcoz weight depends on both mass and gravity

since the gravity of earth and moon is different then the weight is also different

mass doesn't change not weight

Answer:

4.60 × 10⁻⁸

Explanation:

From the given information;

Assuming that q charges are transferred, then:

[tex]F = \dfrac{kq^2}{d^2}[/tex]

where;

k = 9 ×10⁹

[tex]900000 = \dfrac{9*10^9 \times q^2}{1.2^2}[/tex]

[tex]q = \sqrt{\dfrac{900000\times 1.2^2 }{9*10^9}}[/tex]

q = 0.012 C

No of the electrons transferred is:

[tex]= \dfrac{0.012}{1.6\times 10^{-19}} C[/tex]

[tex]= 7.5 \times 10^{16} \ C[/tex]

Initial number of electrons =  N × 47 × no  of moles

here;

[tex]\text{ no of moles }= \dfrac{6.2}{107.87}[/tex]

no of moles = 0.0575 mol

∴

Initial number of electrons =  [tex]6.023\times 10^{23} \times 47 \times 0.0575 mol[/tex]

= 1.63 × 10²⁴

The fraction of electrons transferred  [tex]=\dfrac{7.5\times 10^{16} }{1.6 3\times 10^{24}}[/tex]

= 4.60 × 10⁻⁸

Answer:

The net field will be the sum of the fields created by each charge.

where the charge Q in a position r' is given by:

E(r) = k*Q/(r - r')^2

Where k is a constant, and r is the point where we are calculating the electric field.

Then for the charge 3q, in the position r₁ = (-d, 0, 0) the electric field will be:

E₁(r) = k*3q/(r - r₁)^2

While for the other charge of -2q in the position r₂ = (d, 0, 0)

The electric field is:

E₂(r) = -k*2*q/(r - r₂)^2

Then the net field at the point r is:

E(r) = E₁(r) + E₂(r) = k*3q/(r - r₁)^2 + -k*2*q/(r - r₂)^2

E(r) = k*q*( 3/(r - r₁)^2 - 2/(r - r₂)^2)

Then if the we want to find the points r = (x, y, z) such that:

E(r) = 0 = k*q*( 3/(r - r₁)^2 - -k*2*q/(r - r₂)^2)

Then we must have:

0 = ( 3/(r - r₁)^2 - 2/(r - r₂)^2)

Also remember that the distance between two points:

(x, y, z) and (x', y', z') is given by:

D = √( (x - x')^2 + (y - y)^2 + (z -z')^2)

Then we can rewrite:

r - r₁ = √( (x - (-d))^2 + (y - 0 )^2 + (z -0)^2)

       = √( (x + d))^2 + y^2 + z^2)

and

r - r₂ =  √( (x - d)^2 + (y - 0 )^2 + (z -0)^2)

       = √( (x - d))^2 + y^2 + z^2)

Replacing that in our equation we get:

0 = ( 3/(√( (x + d))^2 + y^2 + z^2))^2 - -k*2*q/(√( (x - d))^2 + y^2 + z^2))^2)

0 = (3/((x + d))^2 + y^2 + z^2) - 2/ (x - d))^2 + y^2 + z^2)

We want to find the values of x, y, z such that the above equation is true.

2/ (x - d))^2 + y^2 + z^2) = (3/((x + d))^2 + y^2 + z^2)

2*[((x + d))^2 + y^2 + z^2] = 3*[(x - d))^2 + y^2 + z^2]

2*(x + d)^2  + 2*y^2 + 2*z^2 = 3*(x - d)^2 + 3*y^2 + 3*z^2

2*(x + d)^2 - 3*(x - d)^2 =  3*y^2 + 3*z^2 -  2*y^2 - 2*z^2

2*(x + d)^2 - 3*(x - d)^2  = y^2 + z^2

2*x^2 + 2*2*x*d + 2*d^2 -  3*x^2 + 3*2*x*d - 3*d^2 = y^2 + z^2

-x^2 + 10*x*d - d^2 = y^2 + z^2

we can rewrite this as:

- ( x^2 - 10*x*d + d^2) =  y^2 + z^2

now we can add and subtract 24*d^2 inside the parenthesis to get

- ( x^2 - 10*x*d + d^2 + 24*d^2 - 24*d^2) =  y^2 + z^2

-( x^2 - 2*x*(5d) + 25d^2 - 24d^2) = y^2 + z^2

-(x^2 - 2*x*(5d) + (5*d)^2) + 24d^2 = y^2 + z^2

The thing inside the parenthesis is a perfect square:

-(x - 5d)^2 + 24d^2 = y^2 + z^2

we can rewrite this as:

24d^2 = y^2 + z^2 + (x - 5d)^2

This equation gives us the points (x, y, z) such that the electric field is zero.

Where we need to replace two of these values to find the other, for example, if y = z = 0

24d^2 = (x - 5d)^2

√(24d^2)  = x - 5d

√24*d = x - 5d

√24*d + 5d = x

so in the point (√24*d + 5d, 0, 0) the net field is zero.

Answer:

The force is now 0.5 N.

Explanation:

Force = 1.5 N

dielectric constant , k = 3

Let the two charges are q and q' and the distance between them is r.

The electrostatic force between the two charges is given by

[tex]F \alpha \frac{ q q'}{r^2}..... (1)[/tex]

When a dielectric material is inserted between the two charges, the new force is

[tex]F' \alpha \frac{ q q'}{kr^2}..... (2)[/tex]

From (1) and (2)

F' = F/K = 1.5/3 = 0.5 N

In a collision that is not perfectly elastic, some of the mechanical energy is converted into other forms.

In a perfect elastic collision, both momentum and kinetic energy of the particles are conserved.

[tex]m_1 u_1 + m_2 u_2 = m_1 v_1 + m_2 v_2[/tex]

[tex]\frac{1}{2} m_1 u_1^2 + \frac{1}{2} m_2 u_2 ^2= \frac{1}{2} m_1 v_1^2 + \frac{1}{2} m_2 v_2^2[/tex]

When the collision is not perfectly elastic, only momentum is conserved but the kinetic energy is not conserved.

Thus, we can conclude that in a collision that is not perfectly elastic, some of the mechanical energy is converted into other forms.

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Answer:

[tex]\mathbf{\mu_s = \dfrac{g}{\omega^2r}}[/tex]

Explanation:

From the given information:

The force applied to the child should be at equilibrium in order to maintain him vertically hung on the wall.

Also, the frictional force acting on the child against gravitational pull is:

[tex]F_f = \mu _sN[/tex]

where,

the centripetal force [tex]F_c[/tex] acting outward on the child is equal to the normal force.

[tex]F_c= N[/tex]

SO,

[tex]F_f = \mu_s F_c[/tex]

Since the centripetal force [tex]F_c = \dfrac{mv^2}{r}[/tex]

Then:

[tex]F_f = \dfrac{ \mu_s \times mv^2}{r}[/tex]

Using Newton's law, the frictional force must be equal to the weight

[tex]F_f = W[/tex]

[tex]\dfrac{ \mu_s \times mv^2}{r} = mg[/tex]

[tex]\dfrac{ \mu_s v^2}{r} = g[/tex]

Recall that:

The angular speed [tex]\omega = \dfrac{v}{r}[/tex]

Therefore;

[tex]g = \mu_s \omega^2 r[/tex]

Making the coefficient of friction [tex]\mu_s[/tex] the subject of the formula:

[tex]\mathbf{\mu_s = \dfrac{g}{\omega^2r}}[/tex]

We call the acceleration of an object moving in uniform circular motion— resulting from a net external force—the centripetal ...

Answer:

ans: 2.25 meter

explanation

use following equations

F = ma

V = U + aT

S = UT + 1/2 aT^2

Answer:

Explanation:

For very low values of the ionic strength the value of the denominator in the expression above becomes nearly equal to one. In this situation the mean activity coefficient is proportional to the square root of the ionic strength. This is known as the Debye–Hückel limiting law.

Answer:

WIND Is what you're looking for

Explanation:

The word is WIND

Answer:

1) 0.3675

2) 0.367

3) 72.6186

4) 0.5

5) 0.000671

Answer:

1) 367.5 mg = 0.3675 g

2) 367 mL = 0.367 L

3) 28.59 in = 72.61 cm

4) 8 0z = 0.5 lb

5) 0.671 mm = 0.0000671 m