a) Show that the surface temperature of a star can be inferred from measurements of blackbodyfluxes at two different frequencies, even if the stellar radius and distance are unknown.
b) Explain why in practice this method does not work well if both frequencies are on theRayleigh-Jeans side of the spectrum,hνkT.
c) Derive a simple, approximate expression for the temperature when both measurements areon the Wien tail,hνkT.
d) Derive an expression for the star’s radius if a distance measurement is also available (e.g.,from parallax).

Answer:

4 meters per second

Explanation:

12 divided by 3 = 4

Explanation:

The force was increased

Answer:

In an ionic bond the valence electrons are transferred from the metal

Explanation:

Answer:

by lying down on a nice and soft quilted matress

Recall that

[tex]{v_f}^2-{v_i}^2=2a\Delta x[/tex]

where [tex]v_i[/tex] and [tex]v_f[/tex] are initial and final velocities, respectively; [tex]a[/tex] is acceleration; and [tex]\Delta x[/tex] is the net displacement, or distance if the object is moving in a single direction.

The car has initial speed 20 m/s and acceleration -3.25 m/s². It comes to a stop, so it has 0 final speed. Then

0² - (20 m/s)² = 2 (-3.25 m/s²) ∆x

∆x = (20 m/s)² / (7.5 m/s²) ≈ 53.3 m

Answer:

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Answer:

uhm- heh, wut lol ️️

If no extra acceleration is added to the rocket, then its velocity at time t is

v = 15 m/s - g t

where g = 9.80 m/s² is the magnitude of the acceleration due to gravity.

Also, recall that

v² - u² = 2 a ∆x

where u is initial speed, v is final speed, a is acceleration, and ∆x is net displacement.

At the rocket's maximum height ∆x, the velocity is 0. So, the maximum height is

0² - (15 m/s)² = 2 (-g) ∆x

∆x = (15 m/s)² / (2 * (9.80 m/s²)) ≈ 11.48 m

But this assumes the rocket is launched from the ground. We're given that the rocket is launced from 3 m above the ground, so we need to add this to the height above. So the maximum height is closer to 14.48 m.

As mentioned before, this happens when vertical velocity is 0:

0 = 15 m/s - g t

t = (15 m/s) / (9.80 m/s²) ≈ 1.53 s

Complete Question

Apollo 14 astronaut Alan B. Shepard Jr. used an improvised six-iron to strike two golf balls while on the Fra Mauro region of the moon’s surface, making what some consider the longest golf drive in history. Assume one of the golf balls was struck with initial velocity v0 = 32.75 m/s at an angle θ = 32° above the horizontal. The gravitational acceleration on the moon’s surface is approximately 1/6 that on the earth’s surface. Use a Cartesian coordinate system with the origin at the ball's initial position.

Randomized Variables

vo 32.75 m/s

theta 32 degrees

What horizontal distance, R in meters, did this golf ball travel before returning to the lunar surface?

Answer:

The  horizontal distance is  [tex]R =  590.2 \ m [/tex]  

Explanation:

From the question we are told that

 The initial  velocity is  [tex]v_o =  32.75 \  m/s[/tex]

  The angle is  [tex]\theta =  26^o[/tex]

  The gravitational acceleration of the moon is [tex]g_m  =  \frac{1}{6}  *  9.8   = 1.633 m/s^2[/tex]

 Generally the distance traveled is mathematically represented as

    [tex]R =  \frac{v_o^2 sin 2(\theta)}{g_m}[/tex]

=> [tex]R =  \frac{32.75^2 sin 2(32)}{1.633}[/tex]

=> [tex]R =  590.2 \ m [/tex]  

Answer:

d) The speed of the astronaut

Explanation:

The sentence describes the speed of the astronaut. This speed value is 10meters per minute.

Now let us understand why;

Therefore, since there is no directional sense, the value indicates speed.

The given sentence describes the speed of the astronaut. Hence, option (d) is correct.

Given data:

The distance covered by the astronaut A is, d = 10 m.

the time interval is, t = 1 min = 60 s.

Clearly,  the given sentence describes the speed of the astronaut. This speed value is 10 meters per minute.  This is because of following reason:

Thus, we can conclude that the given sentence describes the speed of the astronaut. Hence, option (d) is correct.

Learn more about the speed here:

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Answer:

Agility or nimbleness is an ability to change the body's position efficiently, and requires the integration of isolated movement skills using a combination of balance, coordination, speed, reflexes, strength and endurance.

Explanation:

Hope this helps I don't know if this is what you were looking for?

Answer:

Explanation:

3.6

Answer:

[tex]F_N=1234.8N[/tex]

Explanation:

Hello.

In this case, since the normal force is opposite to the total present weight, we can compute it by considering the mass of the classmate with the gravity to compute its weight, and the weight of the table:

[tex]F_N=63kg*9.8m/s^2+500N\\\\F_N=617.4N+500N\\\\F_N=1234.8N[/tex]

Best regards.

Answer:

Option (D).

Explanation:

For an ideal spring, the force is given in terms of displacement as follows :

F=-kx

[tex]x=\dfrac{-F}{k}\\\\\text{or}\\\\x=\dfrac{-1}{k}F[/tex]...(1)

Where,

x is displacement in spring i.e. compression or stretching

k is spring constant of the spring

-ve sign shows that the force exerted by the spring is in opposite direction of the spring's displacement.

The equation of a line is : y=mx+c, m is slope

From equation (1)

Slope = 1/k

or

Slope = reciprocal of the spring's constant.

It would mean that the slope of the curve represents the reciprocal of the spring's constant.

Using the spring constant and displacement relation, the slope of the curve would be the reciprocal of the spring's constant.

Using the Force constant relation :

F = Force ; k = spring constant ; e = extension

Making the x the subject of the formula :

The slope, which is the spring constant can be expressed as ;

Hence, the slope is the reciprocal of the spring constant.

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Answer:

Time taken = 8.25 second

Explanation:

Given:

Force = 4000 N

Force = ma

4,000 = (1100)(a)

Acceleration = 3.6363 m/s²

v = u + at

0 = 30 + (3.6363)t

Time taken = 8.25 second

The time taken by the car to stop is 8.26 s.

Given data:

The mass of car is, m = 1100 kg.

The speed of car is, u = 30 m/s.

The magnitude of braking force is, F = 4000 N.

We need to first obtain the acceleration of car to get that, apply the Newton's second law as,

F = - ma    (Negative sign shows that the force will resist the motion)

4000 = -(1100) a

[tex]a =-\dfrac{4000}{1100}\\\\a =-3.63 \;\rm m/s^{2}[/tex]

Now, apply the first kinematic equation of motion to obtain the time taken by the car to stop as,

v = u + at

Here, v is the final speed and v = 0, since car will stop finally.

So,

[tex]0=30+(-3.63)t\\\\t = \dfrac{30}{3.63}\\\\t=8.26 \;\rm s[/tex]

Thus , we can conclude that the time taken by the car to stop is 8.26 s.

Learn more about the Newton's second law of motion here:

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Answer:

Explanation:

1) True. The stored energy (U) is proportional to the electric field strength (E). The electric field strength decreases when a dielectric is introduced hence inserting a dielectric decreases U.

2) False. From the formula [tex]C=\frac{Q}{V}=\frac{Q}{Vd}[/tex], capacitance is inversely proportional to distance hence if the distance is doubled, capacitance decreases.

3) False. As the distance between the electric field and the object increases, its electric field decreases.

4) False. If a dielectric is inserted, the plates are further separated. Q stays the same.

5) True. The electric field strength decreases when a dielectric is introduced and  capacitance is inversely proportional to electric field hence Inserting a dielectric increases C

6) True. If a dielectric is inserted, the plates are further separated. Q stays the same.

7) True. When the distance is doubled, U increases

Answer:

The average electrical power dissipated in the process is 0.653 mW

Explanation:

Given;

gauge of copper wire, 20 gauge

resistivity from chart, [tex]\rho = 1.68 *10^{-8} \ ohm.m[/tex]

radius of the circular loop, r = 25 cm

magnetic field strength, B = 10 .0 mT

time, t = 0.34 s

Length of the wire, L = 2πr = 2 x π x 0.25 = 1.571 m

Area of the wire, A = πR² ⇒ R = D/2 = 0.8118 mm/ 2 = 0.4059 mm

= π(0.4059 x 10⁻³)² = 0.5177 x 10⁻⁶ m²

The resistance of the wire is given by;

[tex]R = \frac{\rho L}{A}\\\\ R = \frac{1.68*10^{-8}*1.571}{(0.5177*10^{-6})}\\\\ R = 5.098 *10^{-2} \ ohms[/tex]

Now, determine the electric potential;

[tex]E = N\frac{d\phi}{dt}\\\\ E = N(\frac{BA}{dt})\\\\ E = 1(\frac{(10*10^{-3})(\pi*0.25^2)}{0.34} )\\\\E = 0.00577 \ V[/tex]

The average power is given by;

P = V²/R

P = (0.00577²) / (5.098 x 10⁻²)

P = 6.53 x 10⁻⁴ W

P = 0.653 mW

Therefore, the average electrical power dissipated in the process is 0.653 mW

Answer:

6. 49.2 m/s

7. 9.18 s

8. 184 m

Explanation:

6. Use Pythagorean theorem.

v₀² = v₀ₓ² + v₀ᵧ²

v₀² = (20 m/s)² + (45 m/s)²

v₀ = 49.2 m/s

7. Given:

Δy = 0 m

v₀ᵧ = 45 m/s

aᵧ = -9.8 m/s²

Find: t

Δy = v₀ᵧ t + ½ aᵧt²

(0 m) = (45 m/s) t + ½ (-9.8 m/s²) t²

0 = 45t − 4.9t²

0 = t (45 − 4.9t)

t = 9.18 s

8. Given:

v₀ₓ = 20 m/s

aₓ = 0 m/s²

t = 9.18 s

Find: Δx

Δx = v₀ₓ t + ½ aₓt²

Δx = (20 m/s) (9.18 s) + ½ (0 m/s²) (9.18 s)²

Δx = 184 m

Answer:

See attached file for the answer

Answer:

Explanation:

you connect vector b with vector a making it head to tail

Answer:

A: Greater than

Explanation:

Momentum (P) implies product of the mass (m) and velocity (v) of a body.

P = mv

It is measured in kgm/s.

Thus the greater the mass of a body, the more its momentum even when moving at a slower velocity. The change in momentum of an object is called its impulse.

Let the mass of the car be represented by [tex]m_{c}[/tex] and that of the truck be represented by [tex]m_{T}[/tex].

Thus,

[tex]m_{T}[/tex] = 5[tex]m_{c}[/tex]

P of the truck = 5[tex]m_{c}[/tex]v

P of the car = [tex]m_{c}[/tex]v

Thus, during collision, the change in momentum of the truck is greater than that of the car.

Answer:

The correct option is B

Explanation:

This question seeks to test the knowledge of the change in momentum and deep understanding of the Newton's first law of motion which states that a substance will continue to be in a state of rest or constant motion unless acted upon by an external force.

The formula for change in momentum is mass multiplied by change in velocity. where change in velocity is final velocity minus the initial velocity.

The mass of the truck is already said to be 5 times larger, the change in velocity of the car will definitely be negative because the car will pushed back by the truck. For instance, if the initial velocity of the car is 50m/s and the final velocity backwards is 10m/s, the change in velocity will be (-10-50) which will equal (-60)

However, for the truck, the change in velocity will still remain positive for the final velocity because it is expected that the truck will still move forward despite the heads-on collision. Hence, if the initial velocity is 50m/s and the final velocity is 10m/s, the change in velocity will be (10-50) which will equal (-40).

Assuming the mass of the car is 1g. From the formula for change in momentum

The truck will be assumed to be (5 × 1) × -40 = -200

The car will be assumed to be 1 × -60 = -60

Hence, the magnitude of change in momentum of the truck will be lesser than the magnitude of the change in momentum of the car.

Answer:

D

Explanation:

They continously go back and fourth on the ray of movement making the tremendous exponent of the scientificalsource behind it

d is the answer

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Answer:

Color.

Explanation:

Hello.

In this case, among the properties minerals have, we list: color , streak which is the color as a powder , hardness , cleavage or fracture , crystalline structure , diaphaneity or degree of transparency, tenacity which is the capacity of its molecules to be held together,  magnetism which is the capacity to attract or repel other magnetic materials , luster which explains if its surface reflects light , odor , taste  and specific gravity which is a relationship between its density and the density of water.

In such a way, since the most of them are known as measurements, we can distinguish among minerals by contrasting those data, nevertheless, color is not a suitable property to identify a material since there could exist minerals with similar colors.

Best regards.

Answer:

Approximately [tex]14\; \rm m[/tex] above the height of the fire hose, assuming that air resistance is negligible and that [tex]g = -9.81\; \rm m \cdot s^{-2}[/tex].

Explanation:

Consider the motion of water particles in two directions: vertical and horizontal.

Assuming that air resistance on the water particles is negligible.

Initial velocity: [tex]v_0 = 25\; \rm m \cdot s^{-1}[/tex]. Angle of elevation: [tex]\epsilon = 60^\circ[/tex]. Calculate the initial velocity of these water particles in these two components:

How much time would it take for a water particle reaches the building from the hose? That particle needs to travel [tex]x(\text{horizontal}) = 45\; \rm m[/tex] at a constant horizontal speed of [tex]v(\text{horizontal}) \approx 12.5\; \rm m \cdot s^{-1}[/tex]. Therefore:

[tex]\displaystyle t = \frac{x(\text{horizontal})}{v(\text{horizontal})} \approx 3.6\; \rm s[/tex].

In other words, that water particle would be approximately [tex]3.6\; \rm s[/tex] into its flight when it hits the building. What would be its height? Assuming that the air resistance on that particle is negligible. The height of that water particle at time [tex]t[/tex] may be modeled using the SUVAT equation:

[tex]\displaystyle x(\text{vertical}) = \frac{1}{2}\, a \, t^{2} + \left[v_0(\text{vertical})\right]\, t[/tex],

where:

Calculate the height of the water particle when it hits the building:

[tex]\begin{aligned}x(\text{vertical}) &= \frac{1}{2}\, a \, t^{2} + \left[v_0(\text{vertical})\right]\, t \\ &\approx \frac{1}{2} \times \left(-9.81\; \rm m \cdot s^{-2}\right) \times (3.6\; \rm s)^2 + 21.7\; \rm m \cdot s^{-1} \times 3.6\; \rm s \\ &\approx 14\; \rm m\end{aligned}[/tex].

Answer:

cosmonaut Yuri Gagarin

Explanation:

On that day in 1961, Russian cosmonaut Yuri Gagarin (left, on the way to the launch pad) became the first human in space, making a 108-minute orbital flight in his Vostok 1 spacecraft.

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Answer: Before the jump, the snowboarder would carry potential energy.

During the jump he will carry kinetic energy.

And after the jump, assuming hes at a full stop, he will carry potential energy once again.

Answer:

Before the jump, the snowboarder would carry potential energy.During the jump he will carry kinetic energy.And after the jump, assuming hes at a full stop, he will carry potential energy once again.                             Explanation:

Answer:

[tex]a=4\frac{m}{s^2}[/tex]

Explanation:

Hello.

In this case, for this uniformly accelerated motion in which the car starts from rest at 0 m/s and travels 18 m in 3.0 s, we can compute the acceleration by using the following equation:

[tex]x_f=x_0+v_0t+\frac{1}{2}at^2[/tex]

Whereas the final distance is 18 m, the initial distance is 0 m, the initial velocity is 0 m/s and the time is 3.0 s, that is why the acceleration turns out:

[tex]a=\frac{2(x_f-v_ot)}{t^2} =\frac{2(18m-0m/s*3.0s)}{(3.0s)^2}\\ \\a=4\frac{m}{s^2}[/tex]

Best regards.

Given the distance travelled and the time taken, the magnitude of  the car's acceleration is 4m/s²

Given the data in the question;

Since the car starts from rest,

Acceleration; [tex]a = \ ?[/tex]

To determine the magnitude of  the car's acceleration

We use the Second Equation of Motion:

[tex]s = ut + \frac{1}{2}at^2[/tex]

Where s is the speed, u is the initial velocity, a is the acceleration and t is the time.

We substitute our values into the equation and solve for "a"

[tex]18m = (0m/s\ * 3.0s) + (\frac{1}{2}\ *\ a\ *\ (3.0s)^2) \\\\18m = 4.5s^2 \ *\ a\\\\a = \frac{18m}{4.5s^2} \\\\a = 4 m/s^2[/tex]

Therefore, the magnitude of  the car's acceleration is 4m/s²

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Answer:

Explanation:

Comets are balls of ice and dust in orbit around the Sun. The orbits of comets are different from those of planets - they are elliptical. A comet's orbit takes it very close to the Sun and then far away again.

Answer:

the answer is D I believe

Answer:

Answer: D

They result in warmer air temperatures near the current.

Explanation:

i took a test with the same question and got it right