Answer:
636.6 W/m²
Explanation:
From the given information:
The area of the circular spot can be calculated as:
A = πr²
A = π(0.5 × 10⁻³ m)²
A = 7.85 × 10⁻⁷ m²
The intensity can be determined by using the formula:
[tex]I = \dfrac{P}{A}[/tex]
[tex]I = \Big ( \dfrac{0.500 \ mW}{\pi (0.5 \times 10^{-3} \ m )^2} \Big) \Big( \dfrac{10^{-3} \ W}{1\ mW} \Big)[/tex]
[tex]I = \dfrac{0.500 \times 10^{-3} }{\pi(0.25 \times 10^{-6} )}[/tex]
I = 636.6 W/m²
15. Explain how the atomic mass of an element is
affected by the distribution of its isotopes in nature.
Answer:
The atomic mass of an element is affected by the distribution of its isotopes because each isotope of an element has a different number of neutrons in the nuclei of its atoms.
Explanation:
please give me brainlyiest if its right
Please help I’m kinda in a rush to get these done
PLEASE HELP! I'LL GIVE BRAINLEST
Answer:
8.162
Explanation:
W=mg
= 2.2 x 3.71
= 8.162 N
A moving man is lifting a box up an inclined plane. Halfway up he sets the box down and rests. Which of the following explains why the box does not slide back down the inclined plane?
a. The force of friction balances the force of gravity.
b. The force of gravity does not affect inclined planes.
c. The force of friction does not affect inclined planes.
d. The force of friction is less than the force of gravity.
Answer: A or B
Explanation: I’m guessing that they even each other out depending on the incline, gravity will help keeping it in place
A car travels 60km in 45 minutes. At the same average speed, how far will it travel in 1 hour 30 minutes?
doing the same amount of work in less time requires more power true or false
Table 1 contains data about two completely ionised samples of pure boron.
Each sample contains only isotopes X and Y.
Table 1
Sample | Number of ions Mass of Charge on
number in sample = ple / kg each ion/ C
fot | 3.50 x 1016 6.31 x 107! +1.60 x 10719
3.50 x 10” 6.20 x 10°? +1.60 x 10°?
Deduce which sample, 1 or 2, contains a greater percentage of isotope Y.
[3 marks]
Answer:
I think it would most likely be 2... but not so sureee
Instead of changing the focal length of the lens, the eyes of amphibians work in a different manner: a set of muscles changes the shape of the eye which increases the distance between the front of the eye and the retina. The world's largest frog, the Goliath frog of west Africa, has an eye with a maximum size similar to a human's: 2.5cm. However, unlike a human, where the focal length is also 2.5cm, the focal length of the Goliath frog's eye is 2.146 cm. What is the maximum distance this frog can see
Answer:
The answer is "15.56 cm".
Explanation:
[tex]v= 2.5 \ cm\\\\f= 2.154 \ cm[/tex]
Calculating object of length is x so:
[tex]u= -x[/tex]
Using formula:
[tex]\to \frac{1}{v}-\frac{1}{u}=\frac{1}{f}\\\\\to \frac{1}{2.5}-\frac{1}{-x}=\frac{1}{2.154}\\\\\to \frac{1}{x}=\frac{1}{2.154}-\frac{1}{2.5}\\\\\to \frac{1}{2.5}-\frac{1}{-x}=\frac{1}{2.154}\\\\\to x= 15.56 \ cm[/tex]
what is the formula for Mass when you have been provided force, time and distance
Answer:
The mass formula is also given as m = F / a If acceleration itself is the gravity, then M = F / g
please mark me as brainleist
Helppppp plsssssssssssssssssssssss thanks 2+2== plzzz help me and 20+67
Answer:
8,6 is the answer to your question
Mass in motion is another way to say
Answer:
Momentum - Momentum is a measurement of mass in motion. Momentum is equal to the mass times the velocity of an object.
Which statement is true?
A)
All waves travel at the same speed through any medium.
B)
All waves travel at the same speed if no medium is present.
Electromagnetic waves require a medium, but mechanical waves do not.
D)
Mechanical waves require a medium, but electromagnetic waves do not
Answer:
B.
Explanation:
CAN YOU HELP MEEEEEEEEEE PLEASEEEE
Answer:
What are your options? also i believe the answer may be ecosystem.
Explanation:
There are both biotic and abiotic factors in an ecosystem. Be cause living organisms Are Biotic. While water and rocks are abiotic which are needed to form an ecosystem.
sound wave of a wave length of 0.56 meters if its speed is 280 m/s what is the wave frequency
Answer:
500 Hz
Explanation:
Formula for finding wave frequency is,
f = c/λ
f = frequency
c = speed (m/s)
λ = wave length (m)
f = c/λ
f = 280/0.56
f = 500
∴ wave frequency is 500 Hz
Help please is for today
Answer:
All of the above.
Explanation:
A person is said to be at rest when he or she is not performing any action. The heartbeat stays normal in this condition.
A person is said to perform a moderate activity when his heart beats faster than the normal rest condition. It requires extra effort within the limit. For example, walking and dancing are examples of moderate activity.
A person is said to perform a vigorous activity when his heart beats much than in moderate activity. It requires a lot of effort over the limit. Running is an example of vigorous activity.
In view of the above information, all the options given in the question are true. Hence, the correct answer will be:
All of the above.
A student is investigating the differences between light waves and sound waves. The student does this by using a capsule filled with solid glass at one end and a vacuum at the other end. The student will transmit waves into the capsule at a 30° angle to the (normal) centerline.
alert your teacher if the image is missing
Which >>TWO<< questions should the student ask, and which predictions are MOST LIKELY correct based on this investigation?
Group of answer choices
question: Can electromagnetic waves and mechanical waves travel from a solid glass medium into a liquid medium?
prediction: The electromagnetic waves will continue through the liquid medium, while the mechanical waves will go no farther.
question: How are electromagnetic waves and mechanical waves affected when traveling from a solid glass medium to a vacuum?
prediction: The electromagnetic waves will continue through the vacuum, while the mechanical waves will go no farther.
question: Can electromagnetic waves and mechanical waves travel from a solid glass medium into a liquid medium?
prediction: Both electromagnetic waves and mechanical waves will bend, showing that they have passed through each medium.
question: How are electromagnetic waves and mechanical waves affected when traveling from a solid glass medium to a vacuum?
prediction: The electromagnetic waves and mechanical waves will continue through the vacuum at a lower speed.
question: How is the speed of electromagnetic waves affected when traveling from a solid glass medium to a vacuum at a 30° angle?
prediction: The electromagnetic waves will travel in a straight line, showing that they have maintained a constant speed.
question: How is the speed of electromagnetic waves affected when traveling from a solid glass medium to a vacuum at a 30° angle?
prediction: The electromagnetic waves will bend downward, showing that they have sped up slightly
Answer:
Explanation:
The investigation is on differences between light waves and sound waves. Because the light and sound are transmitted at a 30° angle at a capsule with glass and vacuum, questions asked should show difference answers for light and sound.
First and third question talk about liquid which is not related here.
Fouth and sixth prediction are wrong as electromagnetic wave will not slow down or speed up in vacuum.
That leaves the second and fifth set as correct answers:
question: How are electromagnetic waves and mechanical waves affected when traveling from a solid glass medium to a vacuum?
prediction: The electromagnetic waves will continue through the vacuum, while the mechanical waves will go no farther.
question: How is the speed of electromagnetic waves affected when traveling from a solid glass medium to a vacuum at a 30° angle?
prediction: The electromagnetic waves will travel in a straight line, showing that they have maintained a constant speed.
Answer:
The two questions and predictions are:
question: How are electromagnetic waves and mechanical waves affected when traveling from a solid glass medium to a vacuum?
prediction: The electromagnetic waves will continue through the vacuum, while the mechanical waves will go no farther.
question: How is the speed of electromagnetic waves affected when traveling from a solid glass medium to a vacuum at a 30° angle?
prediction: The electromagnetic waves will travel in a straight line, showing that they have maintained a constant speed.
Explanation:
light is EM wave which is transverse while sound is longitudinal. speed changes for long wave but not EM.
Heat transfer in liquids or gases that happens due to currents of hot and cold is called
Entropy
Conduction
Convection
Radiation
Answer:
convection it's your answer plz make me brainy least
Disk A, with a mass of 2.0 kg and a radius of 70 cm , rotates clockwise about a frictionless vertical axle at 50 rev/s . Disk B, also 2.0 kg but with a radius of 50 cm , rotates counterclockwise about that same axle, but at a greater height than disk A, at 50 rev/s . Disk B slides down the axle until it lands on top of disk A, after which they rotate together. After the collision, what is their common angular speed (in rev/s) and in which direction do they rotate?
Answer:
w = - 197.5 rad / s
The negative sign indicates that the rotations are clockwise
Explanation:
To solve this exercise, let's use the concept of conservation of the angular number.
We create a system formed by the two discs, in this case the forces last the shock are internal
initial instant .. just before shock
L₀ = I₀ w₀ + I₁ w₁
instnte final. Right after crash
L_f = (I₀ + I1) w
angular momentum is conserved
I₀ w₀ + I₁ w₁ = (I₀ + I₁) w
w = I₀ w₀ + I₁ w₁ / Io + I1
The moment of inertia of a disk with an axis passing through its thermometric center
I₀ = ½ m² r₀²
I₁ = ½ m₁ r₁²
we substitute
I₀ = ½ 2.0 0.70²
I₀ = 0.49 kg m
I₁ = ½ 2.0 0.5²
I₁ = 0.25
₁
let's reduce the magnitudes the SI system
w₀ = -50 rev / (2pi rad / 1rev) = -314.15 rad / s
w₁ = 70 rev (2pi rad / 1rev) = 439.82 rad / s
we will assume that the counterclockwise turns are positive
w = -0.49 314.15 + 0.25 439.82 / (0.49 + 0.25)
w = (- 4.696 + 1.0995) 102) / 0.74
w = -197.75 + 0.25
w = - 197.5 rad / s
The negative sign indicates that the rotations are clockwise
the density of gold is 19g/m³ what is the volume of 38g
let the volume be x
19 = 38/x
x=38/19
x=2
volume is 2 cm^3
someone painted the building last year.into passive
Answer:
The building was Painted
The building was painted last year by someone.
Drink water at least every
weather.
minutes while exercising in hot
Answer:
Drink water at least every 5 to 20 minutes while exercising in hot weather.
Explanation:
Hope this helps brainliest please
a disk of radius 10 cm speeds up from rest. it turns 60 radians reaching an angular velocity of 15 rad/s. what was the angular acceleration?
b. how long did it take the disk to reach this velocity?
Answer: [tex]1.875\ rad/s^2, 8\ s[/tex]
Explanation:
Given
Radius of disc [tex]r=10\ cm[/tex]
Angle turned [tex]\theta=60\ rad[/tex]
Initial angular velocity [tex]\omega_0=0[/tex]
Final angular velocity [tex]\omega_f=15\ rad/s[/tex]
using [tex]\omega^2-\omega_o^2=2\alpha \cdot \theta[/tex]
Substitute values
[tex]\Rightarrow 15^2-0=2\times \alpha \times 60\\\Rightarrow \alpha=1.875\ rad/s^2[/tex]
using [tex]\omega=\omega_o+\alpha t[/tex]
Substitute values
[tex]\Rightarrow 15=0+1.875\times t\\\Rightarrow t=8\ s[/tex]
How much power is required to do 10 J of work on an object in 2 seconds?
Answer:
5 watts
power = work done ÷ time taken
10 j ÷ 2 = 5w
HELP HELP HELP HELP HELP PLEASEEE HELP ME WITH MY OTHER QUESTIONS TOO!! PLEASE
can someone help
pls !
A car covers 8m in the first second and 12m in the second second. Find
a) Initial Velocity
b) Acceleration
c) Distance covered in the third second
Explanation:
Given that,
Distance travelled by the car in first second = 8 m⠀⠀⠀⇒ S′ = u + a/2(2n ― 1)
⠀⠀⠀⇒8 = u + a/2× [2(1) ― 1]
⠀⠀⠀⇒8 = u + a/2× [2 ― 1]
⠀⠀⠀⇒8 = u + a/2× 1
⠀⠀⠀⇒8 = u + a/2⠀⠀⠀⠀⠀ … ( 1 )
And,
Distance travelled by the car in second second = 12 m⠀⠀⠀⇒ S″ = u + a/2(2n ― 1)
⠀⠀⠀⇒12 = u + a/2× [2(2) ― 1]
⠀⠀⠀⇒12 = u + a/2× [4 ― 1]
⠀⠀⠀⇒12 = u + a/2× 3
⠀⠀⠀⇒12 = u + 3a/2⠀⠀⠀⠀ … ( 2 )
Subtract ( 1 ) from ( 2 ).
⠀⠀⠀⇒12 ― 8 = u + 3a/2 ― (u + a/2)
⠀⠀⠀⇒4 = u + 3a/2 ― u ― a/2
⠀⠀⠀⇒4 = 3a/2 ― a/2
⠀⠀⠀⇒4 = 2a/2
⠀⠀⠀⇒4 × 2 = 2a
⠀⠀⠀⇒8 = 2a
⠀⠀⠀⇒8 ÷ 2 = a
⠀⠀⠀⇒4 m/s² = a⠀⠀⠀⠀⠀[Ans]
Substitute the value of a in equation ( 1 ).
⠀⠀⠀⇒8 = u + a/2⠀⠀⠀⠀⠀ … ( 1 )
⠀⠀⠀⇒8 = u + 4/2
⠀⠀⠀⇒8 = u + 2
⠀⠀⠀⇒8 ― 2 = u
⠀⠀⠀⇒6 m/s = u⠀⠀⠀⠀⠀[Ans]
Now, distance travelled in third second.
⠀⠀⠀⇒ S′″ = u + a/2(2n ― 1)
⠀⠀⠀⇒ S′″ = 6 + 4/2 × [2(3) ― 1]
⠀⠀⠀⇒ S′″ = 6 + 2 × [6 ― 1]
⠀⠀⠀⇒ S′″ = 6 + 2(5)
⠀⠀⠀⇒ S′″ = 6 + 10
⠀⠀⠀⇒ S′″ = 16 m⠀⠀⠀⠀⠀[Ans]
CORRECT ANSWER GETS BRAINLIEST
Answer:
Wax melts as it absorb heat from flame
Explanation:
To know which option is correct, it is important that we know what chemical changes and physical changes are all about.
Chemical change is a change in which the process is not easily reversed and it produces new substance.
Physical change is more like the opposite of chemical change. In this change, the process is easily reversed and no new substance is produced.
Considering the options given above,
1. Iron combines with oxygen to produce rust is a chemical change since a new substance (rust) is formed and we can not reverse the process to get back iron and oxygen.
2. Wax melts as it absorb heat from flame is a physical change since no new substance is formed and we obtained the wax by allowing it to solidified.
3. Pure sodium explodes when dropped in water is a chemical change because we can not reverse the process to get back the sodium.
4. Glucose molecules are produced in plant leaf is also a chemical change.
From the illustrations above, it is evident that: 'Wax melts as it absorb heat from flame' is not a chemical
Ilus
A bat bounces a sound wave off a
bird 19.4 m away, and hears the
echo after 0.117 s. What is the
speed of sound in the air?
(Hint: It is not necessarily 343 m/s.)
(Unit = m/s)
Answer:
332m/s
Explanation:
We know the formula for velocity is v=d/t, but this particular question is asking about an echo. The problem tells us the distance to the bird from the bat, which is 19.4. To find the echo, you need to find the distance from the bat to the bird and back.
So
19.4 x 2 = 38.8
And then plug into the equation
v = 38.8 / 0.117
= 332m/s
Explain why synovial joints have greater flexibility than fixed and cartilaginous joint.
Answer:Unlike fixed joints or cartilaginous joints, where the bones are connected by either connective tissue or cartilage, the bones in synovial joints are not directly joined by anything, which allows for a much greater range of motion.
Explanation: I got a 100% on my test
A simple mass spectrometer may include an electron ionization (EI) source and magnetic sector mass analyzer. In this type of instrument, singly charged ions are produced and accelerated through the slit to the analyzer by applying high potentials to accelerator plates. If an ion with mass 400 amu and charge z = 1 is accelerated by a potential of 4000 V, what is its kinetic energy (in J)?
Answer:
K.E = 6.4 × 10⁻¹⁶
Velocity = 4.39 × 10⁴ m/sec
Explanation:
From the given information:
The average K.E = P.E (potential energy)
Thus, K.E = q × V
K.E = 1.6 × 10⁻¹⁹ × 4000 V
K.E = 6.4 × 10⁻¹⁶
However,
[tex]K.E = \dfrac{1}{2}mv^2[/tex]
[tex]6.4 \times 10^{-16} = \dfrac{1}{2}(400 \times 1.66 \times 10^{-27} ) \times v^2[/tex]
[tex]\dfrac{6.4 \times 10^{-16} }{\dfrac{1}{2}(400 \times 1.66 \times 10^{-27} )}= v^2[/tex]
[tex]v^2=1.92771084 \times 10^9\\ \\ v=\sqrt{ 1.92771084 \times 10^9} \\ \\ v = 43905.7 \\ \\ \mathbf{v = 4.39 \times 10^4 \ m/sec}[/tex]