Câu 2. Cho một bóng đèn pin đang được bật sáng như hình vẽ.
a. Chùm sáng do dây tóc bóng đèn phát ra là chùm sáng gì?
-Phân kì
b. Dùng một tờ bìa có đục một lỗ tròn nhỏ. Hãy nêu cách làm để khẳng định kết luận về
tên gọi của chùm sáng vừa trả lời ở câu a.

Answer:

Explanation:

To solve this problem, we can use the principles of conservation of momentum and conservation of kinetic energy.

To calculate the direction of the final velocity of the bowling ball, we can use the concept of vector addition. We know that the bowling pin is scattered at an angle of θ = 23.5° from the initial direction of the bowling ball. Therefore, the final velocity of the bowling ball will be at an angle of 180° - θ = 156.5° from its initial direction.

To calculate the magnitude of the final velocity of the bowling ball, we can use the conservation of momentum. The initial momentum of the system (bowling ball and bowling pin) is given by:

Initial momentum = m1 * v1 + m2 * v2

where m1 and v1 are the mass and velocity of the bowling ball, and m2 and v2 are the mass and velocity of the bowling pin, respectively.

Initial momentum = (5.75 kg * 9.85 m/s) + (0.95 kg * 11 m/s)

Simplifying this equation gives us the initial momentum.

Next, we can use the conservation of momentum to determine the final velocity of the bowling ball. Since there are no external forces acting on the system, the total momentum before the collision is equal to the total momentum after the collision.

Final momentum = Initial momentum

Since we know the mass of the bowling ball and the final velocity of the bowling pin, we can calculate the final velocity of the bowling ball.

Finally, the magnitude of the final velocity of the bowling ball can be found by taking the magnitude of the final velocity vector calculated in step 2.

Please note that for more accurate results, the calculations should consider the vector nature of the velocities.

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Answer:

The correct option is;

C. 25 m/s

Explanation:

The initial velocity with which the boulder was thrown = 25 m/s

The path in which the boulder projectile moves = 30°

For projectile motion, we have;

The time it takes the boulder to hit the ground is given by the following equation;

y = y₀ + v₀·sin(θ₀)t -¹/₂·g·t²

Where;

y = The height of the boulder

y₀ = The initial height of the boulder = 0

g = The acceleration due to gravity = 9.81 m/s²

When the boulder touches the ground again, the value  of y = 0. therefore, we have;

0 = 0 + 25 × sin(30)t -¹/₂ × 9.81 × t²= 12.5·t - 4.905·t²

From which we have, t = 0 or t ≈ 2.55 s

At t = 2.55 s The vertical velocity = v₀sin(θ₀) - g·t = 25 × 0.5 - 9.81×2.55 =  -12.5 m/s

The vertical velocity, \(v_y\) =  -12.5 m/s

The horizontal velocity, vₓ = v₀·cos(θ₀) = 25×cos(30) ≈ 21.65 m/s

The magnitude of the resultant velocity before, the boulder hits the ground is given as follows

\(\left | v \right |\) = √((vₓ)² + (\(v_y\))²) = √(12.5² + 21.65²) = √625 = 25

The magnitude of the resultant velocity before, the boulder hits the ground is 25 m/c

The photon with an energy of \(9.01 * 10^{-19}\) J has a wavelength of approximately 220.3 nm.

To find the wavelength of a photon given its energy, we can use the equation:

E = hc/λ

Where:

E is the energy of the photon,

h is the Planck's constant (approximately 6.62607015 × 10^-34 J·s),

c is the speed of light in a vacuum (approximately 2.998 × 10^8 m/s),

λ is the wavelength of the photon.

Rearranging the equation to solve for λ, we have:

λ = hc/E

Given:

\(E = 9.01 * 10^{-19}\) J

Substituting the known values:

\(\lambda = \frac{(6.62607015 * 10^{-34} * 2.998 * 10^8 )}{(9.01 * 10^{-19}}\)

\(\lambda = \frac{(1.98644591 * 10^{-25})}{(9.01 * 10^{-19})}\)

\(\lambda \approx 2.203 * 10^{-7} m\)

To convert this wavelength to nanometers, we can multiply by 10⁹:

=λ ≈ 220.3 nm.

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According to the Theory of Continental Drift, we can predict that:

Continental Drift can be defined as a hypothesis that was put forth, that the Earth's continents have moved over  time relative to each other and as the time goes its keeps on moving, increasing the distance between them.

Continental Drift makes the continents look like they have drifted across the ocean.

In conclusion, Our predictions are stated above.

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It is necessary to collimate the light source before using the prisim to  disperse the light so that the light rays entering the prisim are parallel series.

What is colimate?

collimator is a tool for converting a point source's divergent radiation into a parallel beam. To perform specific measurements in spectroscopy, geometrical optics, and physical optics, the light must be collimated.

An optical collimator is made up of a tube with a convex lens at one end and a variable aperture at the other end that is located in the lens' focal plane. To examine the image without parallax, radiation entering the aperture exits the collimator as a parallel beam.

Therefore collimation is needed for the light rays entering the prism to be parallel .

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Explanation:

F=m(v-u)/t

F=2N

m=2kg

t=2s

2=2(v-u)/2

cross multiply

2*2=2(v-u)

4=2(v-u)

4/2=v-u

v-u=2m/s

v-u is the change is velocity.

The change in velocity of the body in 2 sec is 2m/s

According to Newton's second law which states that the change in momentum of an object is directly proportional to the applied force.

Mathematically:

\(F \ \alpha \ (\dfrac{v-u}{t} )\)

\(F = m (\dfrac{v-u}{t} )\)

where:

m is the mass

(v - u) is the change in velocity

t is the time

F is the applied force

Given the following:

mass m = 2kg

time t = 2secs

Force F = 2N

Required

Change in velocity (v-u)

Substitute the given parameters into the expression shown above:

\(2=2(\dfrac{v-u}{2})\\ 2 \times 2=2(v-u)\\4=2(v-u)\\v-u=\dfrac{4}{2}\\v-u=2m/s\\\)

Hence the change in velocity of the body in 2 sec is 2m/s.

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Answer:

Coerce, compel, constrain

Explanation:

Answer:

Approximately \(0.388\; {\rm s}\), assuming that air resistance is negligible and that \(g = 9.81\; {\rm m\cdot s^{-2}}\).

Explanation:

Initial vertical velocity of the object: \(u = 11.0\; {\rm m\cdot s^{-1}}\), upwards (same as that of the rollercoaster.)

Initial height of the object: \(h_{0} = 5.00\; {\rm m}\).

If air resistance is negligible, this object will accelerate downwards at a constant \(a = (-g) = (-9.81)\; {\rm m\cdot s^{-2}}\). Note that \(a\) is negative since the object is accelerating downwards.

The SUVAT equation \(h = (1/2)\, a\, t^{2} + u\, t + h_{0}\) gives the height \(h\) of this object at time \(t\). Note that while the initial height is \(5.00\; {\rm m}\), \(h = 0\) when the object reaches the ground.

Since acceleration \(a\), initial velocity \(u\), and initial height \(h_{0}\) are all given, setting \(h\!\) to \(0\) and solving for \(t\) will give the time it takes for this object to reach the ground:

\((1/2)\, a\, t^{2} + u\, t + h_{0} = 0\).

\((1/2)\, (-9.81) \, t^{2} + 11.0\, t + 5.00 = 0\).

\((-4.905)\, t^{2} + 11.0\, t + 5.00 = 0\).

Solve this equation for \(t\!\) using the quadratic formula. Note that \(t > 0\) since \(t\) denotes the amount of time required for the object to reach the ground.

\(\begin{aligned} t &= \frac{-11.0 + \sqrt{11.0^{2} - 4 \times (-4.905) \times 5.00}}{2\times (-4.905)} \\ &\approx 0.388\; {\rm s}\end{aligned}\).

The other root of this quadratic equation is negative and isn't a valid solution to the question.

In other words, it will take approximately \(0.388\; {\rm s}\) for this object to reach the ground.

Answer:

El edificio tiene una altura de aproximadamente 0.548 m

Explanation:

Podemos utilizar las ecuaciones del movimiento en dos dimensiones para resolver este problema. En primer lugar, podemos descomponer la velocidad inicial en sus componentes horizontal y vertical. Dado que la velocidad inicial es únicamente horizontal, la componente horizontal de la velocidad es de 30.0 m/s, mientras que la componente vertical es cero.

A continuación, podemos utilizar la ecuación de la posición vertical para determinar la altura del edificio. Esta ecuación es:

y = y0 + v0y t + (1/2) a_y t^2

donde y es la posición vertical final, y0 es la posición vertical inicial (en este caso, la altura del lanzamiento), v0y es la componente vertical de la velocidad inicial (en este caso, cero), a_y es la aceleración vertical (en este caso, la aceleración debido a la gravedad, que es de -9.8 m/s^2), y t es el tiempo de vuelo.

La distancia horizontal recorrida durante el vuelo es de 10.0 m, y la componente horizontal de la velocidad es de 30.0 m/s, por lo que podemos calcular el tiempo de vuelo como:

t = d / v0x = 10.0 m / 30.0 m/s = 0.333 s

Sustituyendo este valor en la ecuación de la posición vertical, y teniendo en cuenta que la velocidad vertical final también es cero (ya que el rollo vuelve al nivel del suelo), podemos despejar la altura del edificio:

y = y0 + (1/2) a_y t^2

y = 0 + (1/2) (-9.8 m/s^2) (0.333 s)^2

y = 0.548 m

Por lo tanto, el edificio tiene una altura de aproximadamente 0.548 m.

anticlockwise = clockwise (Force*distance)

1 * 20 = 2 * x

x = 10

If a metal ball is suspended by a rod , the forces acting on the system are balanced so there is no motion observed in the system and this is because of the upward tension in the rod .

Option 1 says : the tension in the rod

The gravitational pull that is acting downwards direction and the tension in rod that is acting in a anti parallel direction to the gravitational pull . being on the same line of action and in opposite directions , these forces cancels each other out .

Option 2 says : the friction of rod

Friction acts in cases of contact forces like a drag or pull not in cases of non-contact forces like gravity , thus friction can't balance it .

Option 3 says : the electromagnetic force

There are no charges or magnets present in the system so the electromagnetic force is absent in this case Thus they cant balance the gravitational force.

Option 4 says : the strong force around the rod

The strong force around is not on the line of action of the gravitational pull so it cant balance it.

So out of all the forces only the tension present in the rod is able to balance the gravitational force

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Answer:

Biosphere are the regions of the surface, atmosphere, and hydrosphere of the earth.

Hydrosphere is when all the waters on the earth's surface, such as lakes and seas, and sometimes including water over the earth's surface, such as clouds.

Atmosphere is the envelope of gases surrounding the earth or another planet.

Explanation:

Hope this helps you out !!!

Distance of train after 1.8 h is 485.099 m

Distance is a measurement of how far apart two things or points are, either numerically or occasionally qualitatively. Distance can refer to a physical length in physics or to an estimate based on other factors in ordinary language.

Distance of the first plane = 650 x 1.8 = 1170 m

Distance of the second plane = 590 x 1.8 = 1062m

The angle between 2 planes

161◦ - 16.9◦ = 144.1°

Using the law of cosine

d^2 = (1170)^2 + (1062)^2 - 2*1170*1062*cos 144.1°

d = 485.099 m

Hence, distance of train after 1.8 h is 485.099 m

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Answer:

Fe = 7.98*10^5N/C

Explanation:

In order to calculate the electric force between the two charges you use the following formula:

\(F_e=k\frac{q_1q_2}{r^2}\)           (1)

k: Coulomb's constant = 8.98*10^9Nm^2/C^2

q1 = 2mC = 2*10^-3C

q2 = 4mC = 4*10^-3C

r: distance between the charge = 30cm = 0.3m

You replace the values of the parameters in the equation (1):

\(F_e=(8.98*10^9Nm^2/C^2)\frac{(2*10^{-3}C)(4*10^{-3}C)}{(0.3)^2}\\\\F_e=7.98*10^5\frac{N}{C}\)

The force between the charges q1 and q2 is 7.98*10^5N/C

A longitudinal wave is a wave in which the motion of the medium's particles is parallel to the wave's direction of propagation.

Longitudinal waves are waves in which the displacement of the medium is in the same (or the opposite) direction as the wave propagation and the medium vibration is parallel ("along") to the direction the wave travels.

Two categories of mechanical waves exist: In longitudinal waves, the movement of the particles is parallel to the motion of the energy, meaning that the medium is displaced in the same direction as the wave.

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The correct answer is: All of these answers are correct.

All the provided explanations can be plausible reasons for the low adoption of a cookstove intervention in rural Bangladesh. It is important to consider factors such as technology maintenance, regional cooking preferences, and the suitability of the chosen stove for the user's level of education.

All of these factors can significantly impact the acceptance and adoption of a new cooking technology.It would hinder their ability to effectively use and benefit from the intervention.

Considering these factors collectively provides insight into why the adoption rate remained low. Addressing these issues is crucial to improving the acceptance and success of cookstove interventions in rural communities.

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Answer:

The bear is actually sharpening his claws. That's the only reason he scratches a tree with his claws

Explanation:

Answer:A convex lens is employed in microscopes and magnifying glasses to converge all incoming light rays to a particular point. ...

The convex lens is used in cameras. ...

A convex lens is used for the correction of hyperopia. ...

The converging lens is used in the projector as well.

a) The mirror's radius of curvature will be 2.7 cm

B)  The magnification of the image will be 4.0.

When a hollow spherical is divided into pieces and the exterior surface of each cut portion is painted, it forms a mirror, with the inner surface reflecting the light.

From the mirror equation;

\(\frac{1}{p}+\frac{1}{q} =\frac{1}{f} \\\\ \frac{1}{1}+\frac{1}{-10} =\frac{1}{f} \\\\ \frac{1}{f} = 1-\frac{1}{10} \\\\ \frac{1}{f} = \frac{9}{10} \\\\ f= 1.1111\)

Hence,

The radius of curvature is twice of the focal length;

\(\rm R = 2f \\\\ \rm R = 2\times 1.111 \\\\ R=2.2222 \ cm\)

Hence, the mirror's radius of curvature will be 2.7 cm.

The magnification factor is found as;

\(\rm m = \frac{-q}{p} \\\\ m = \frac{-(-10)}{1} \\\\ m = 10\)

Hence, the magnification of the image will be 4.0.

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A cosmic day is equivalent to approximately 13.8 billion Earth years.

To calculate how many Earth years a cosmic day is equivalent to, we need to determine the length of a cosmic year in Earth years and then divide it by 365 to find the duration of a cosmic day.

Given that the age of the universe is estimated to be 13.8 billion normal years, and only one cosmic year has passed in that time, we can conclude that a cosmic year is equal to 13.8 billion normal years.

To convert this into Earth years, we multiply the length of a cosmic year by 365, since there are 365 days in a normal year.

13.8 billion normal years * 365 = 5.04 trillion Earth years.

Now, to find the duration of a cosmic day, we divide the length of a cosmic year in Earth years by 365 (the number of cosmic days in a cosmic year).

5.04 trillion Earth years / 365 = 13.8 billion Earth years.

Therefore, a cosmic day is equivalent to approximately 13.8 billion Earth years.

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Answer:

When a switch is closed, electrons move through a circuit from the negative side of a battery to the positive side

Explanation:

Note that current is marked to flow from positive to negative on circuit diagrams, but that's for historical reasons only. Benjamin Franklin did a fabulous job of understanding what was going on, but no one yet knew about protons & electrons, so he assumed current was flowing from positive to negative.

However, what really happens is electrons flow from negative (where they repel each other) to positive (where they are attracted).

As electrons flow through a circuit, they need 'something to do'. In many cases, that something is to light a bulb or heat an element, such as an element on a stove. So, the energy of an electron can be converted to heat or light.

I hope I'm understanding your question correctly

Answer: When a raccoon eats a fruit it eats the seeds that are in the fruit. When the raccoon goes to the bathroom it expels the seeds that are in the feces which plants them.

Answer:

The raccoon is helping to spread the seeds of the plant

Explanation:

The average speed is r=50 mph

Teenagers, young adults, and others use the stimulant medication known as "speed" to feel more focused and alert, and occasionally to get euphoric. Several types of speed are also used by some people to suppress their appetite. Different speed types include: Amphetamines (used to treat ADHD, narcolepsy, and depression)

In essence, an object's speed indicates how quickly it is moving. Its velocity reveals how quickly it is moving in a specific direction. In your daily life, you utilize speed measures, but in physics, velocity measurements are more frequently used.

distance=rate*time

total distance=rate*total time

to Grandmother's...

50=34*t

50/34=t

t=25/17 hours for the first 50 miles

50=66*t

50/66=t

t=25/33 hours for the second 50 miles

total distance=50+50=100 miles

total time=25/17+25/33

total time=(825/561)+(425/561)=1250/561 hours

total distance=rate*total time

100=r*(1250/561)

r=(100)(561/1250)

r=56,100/1250

r=5610/125

r=1122/25

r=44.88 mph is the average speed (rounded it is 44.9 mph)

Note: If you are familiar with the simplified form of the harmonic mean you can solve the problem that way. If not, that's okay. You can look it up if you like.

(2*34*66)/(34+66)=4488/100=44.88 again

from Grandmother's house...

because the times are the same you simply add the 2 rates and divide by 2

(34+66)/2=100/2=50 mph is the average speed

d=r*t

100=34*t+66*t (the times are the same, t)

100=100*t

t=1 hour traveling at 34 mph and 1 hour traveling at 66 mph for a total of 2 hours traveling

d=r*t

100=r*2

r=100/2

r=50 mph is the average speed

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Answer:  B

Explanation:

Linear acceleration and angular acceleration are directly proportional. The greater the linear acceleration, the larger the angular acceleration.

For example, the greater the angular acceleration of a bike's wheels, the greater the acceleration of the bike.

The apparent weight of a 92-kg astronaut aboard this rocket 3707 N.

A rocket launches with an acceleration of 30.5 m/s2.

velocity = 30.5 m/s2

astronaut weighs 92 kg.

To locate

The astronaut's apparent weight is equal to

Solution:

According to, the astronaut's overall weight in a rocket is

W = w + F

W stands for the astronaut's perceived weight

astronaut weight on Earth's surface: grams

F = astronaut's force multiplied by ma

W = mg+ma

W = m (g+a)

W = 92 (9.8 + 30.5)

W = 3707 N

As a result, the astronaut in the rocket appears to weigh 3707 N.

The apparent weight of a 92-kg astronaut aboard this rocket 3707 N.

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Answer:

1. An encounter with the barrier

2. The distance traveled by the washer.

Explanation:

Answer:

Peep above me is correct

1.An encounter with the barrier

2.The distance traveled by the washer

Explanation:

got it right on edge2020 have a nice day peeps ^w^

Answer:

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

\(a = \frac{f}{m} \\ \)

f is the Force

m is the mass

From the question we have

\(a = \frac{25}{40.5} \\ = 0.617283950...\)

We have the final answer as

Hope this helps you

Answer:

Mass

Explanation:

Answer:

mass

Explanation: less room is taken up