Answer:
true
true
false
true
pls follow me and thank you
Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1.00 W/m2 . (a) If a radar unit leaks 10.0 W of microwaves (other than those sent by its antenna) uniformly in all directions, how far away must you be to be exposed to an intensity considered to be safe
Answer:
We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.
Explanation:
Let suppose that intensity is distributed uniformly in a spherical configuration. By dimensional analysis, we get that intensity is defined by:
[tex]I = \frac{\dot W}{\frac{4\pi}{3}\cdot r^{3}}[/tex] (1)
Where:
[tex]I[/tex] - Intensity, measured in watts per square meter.
[tex]r[/tex] - Radius, measured in meters.
If we know that [tex]\dot W = 10\,W[/tex] and [tex]I = 1\,\frac{W}{m^{2}}[/tex], then the radius is:
[tex]r^{3} = \frac{\dot W}{\frac{4\pi}{3}\cdot I }[/tex]
[tex]r = \sqrt[3]{\frac{3\cdot \dot W}{4\pi\cdot I} }[/tex]
[tex]r = \sqrt[3]{\frac{3\cdot (10\,W)}{4\pi\cdot \left(1\,\frac{W}{m^{2}} \right)} }[/tex]
[tex]r \approx 1.337\,m[/tex]
We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.
A 200 kg motorcycle speeds at 90 mph (40 m/s) off of a highway overpass and lands on top of a 18,000 kg semi truck, which is traveling in the same direction at 65 mph (30 m/s). Assume both vehicles stick together are coasting without friction after the collision. What will be the final speed of the semi truck after the collision
Answer:
The final speed of the semi truck is 30.11 m/s.
Explanation:
Given;
mass of the motorcycle, m₁ = 200 kg
initial speed of the motorcycle, u₁ = 40 m/s
mass of the semi truck , m₂ = 18,000 kg
initial speed of the semi truck, u₂ = 30 m/s (same direction as u₁)
If the two vehicles stick together after collision, the final speed of the motorcycle will be equal to final speed of the semi truck = v
Apply the principle of conservation of linear momentum;
m₁u₁ + m₂u₂ = v(m₁ + m₂)
(200 x 40) + (18,000 x 30) = v(200 + 18,000)
8000 + 540,000 = v(18,200)
548,000 = v(18,200)
[tex]v = \frac{548,000}{18,200} \\\\v = 30.11 \ m/s[/tex]
Therefore, the final speed of the semi truck is 30.11 m/s.
An electron traverses a vacuum tube with a length of 2 m in 2 X 10- 4
sec. What is the average speed of the
electron during this time?
Answer:
[tex]v=10^4\ m/s[/tex]
Explanation:
Given that,
The length of a vacuum tube, d = 2 m
Time, [tex]t=2\times 10^{-4}\ s[/tex]
We need to find the average speed of the electron during this time. Average speed is equal to total distance covered divided by total time taken.
Here, total distance = length of the vacuum tube
[tex]v=\dfrac{2}{2\times 10^{-4}}\\\\=10^4\ m/s[/tex]
So, the average speed of the electron is [tex]10^4\ m/s[/tex].
If the entire population of Earth were transferred to the Moon, how far would the center of mass of the Earth-Moon-population system move
The question is incomplete. The complete question is :
If the entire population of Earth were transferred to the Moon, how far would the center of mass of the Earth-Moon population system move? Assume the population is 7 billion, the average human has a mass of 65 kg, and that the population is evenly distributed over both the Earth and the Moon. The mass of the Earth is 5.97×1024 kg and that of the Moon is 7.34×1022 kg. The radius of the Moon’s orbit is about 3.84×105 m.
Solution :
Given :
Mass of earth, [tex]$M_e = 5.97 \times 10^{24} \ kg$[/tex]
Mass of moon, [tex]$M_m = 7.34 \times 10^{22} \ kg$[/tex]
Mass of each human, [tex]$m_p =65 \ kg$[/tex]
Therefore mass of total population, [tex]$M_p = 65 \times 7 \times 10^{9} \ kg$[/tex]
[tex]$M_p = 4.55 \times 10^{11} \ kg$[/tex]
Let the earth is at the origin of the coordinate system. Then,
Since [tex]$M_e>> M_p$[/tex]
[tex]$M_m>> M_p$[/tex]
Hence if we shift all the population on the moon there will be negligible change in the mass of the moon and earth. Hence there will not be any significant shift on the centre of mass. i.e.
[tex]$X_{cm} = \frac{5.97 \times 10^{24}+ 7.34 \times 10^{22} \times 3.84 \times 10^5}{5.97 \times 10^{24}+ 7.34 \times 10^{22}}$[/tex]
[tex]$= 4.68 \times 10^6 \ m$[/tex]
[tex]$ 4.68 \times 10^3 \ km$[/tex] from the earth.
A 60.0 kg woman runs up a staircase 15 m high (vertically) in 20. s. (a) How much power does she expend
Given that,
Mass of a woman, m = 60 kg
She runs up a staircase 15 m high in 20 s.
To find,
Power expanded.
Solution,
Power = rate of doing work
[tex]P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{60\times 9.8\times 15}{20}\\\\=441\ W[/tex]
So, the required power is 441 W.
Consider the standing wave on a guitar string and the sound wave generated by the string as a result of this vibration. What do these two waves have in common
Answer:
As the string vibrates, it "moves" the particles in the air, generating what we know as a soundwave.
Because this soundwave is generated by the wave-like motion of the string, makes sense that the soundwave will have some characteristics in common with the standing wave on the guitar string. This means that both waves will have the same normal modes. (So if the principal mode of the vibrating string has a frequency of 440hz, to soundwave also will have that main frequency, and we will hear an A). You can hear almost all the normal modes when you pluck a guitar string, particularly in music, these are called "overtones" or "harmonics"
A concave mirror creates a real, inverted image 16.0 cm from its surface. If the image is 3.5 times larger, how far away is the object? Use the GUESS method to solve the problem and show all your work. Record you final answer using the correct number of significant digits
Answer:
3.6, make sure you study
The label on a bottle of soda can shows the can contains 397 ml of soda how many litters of soda are in one can
A.)0.397 L
B.)3.97 L
C.)39,700 L
D.)397,000L
Answer:
A
Explanation:
1000ml = 1l
397ml = 0.397l
Two forces act on a 7.5-kg object. One of the forces is 10.0 N. If the object accelerates at 1.97 m/s2, what is the greatest possible magnitude of the other force
Answer:
24.775N
Explanation:
According to Newton's second law
\sum Fx = ma
F- Ff = ma
F and Ff are the forces acting on the object
m is the mass
a is the acceleration
Given
Ff = 10N
m = 7.5kg
a = 1.97m/s²
Required
F
Substitute the given parameters into the formula
F - 10 = 7.5(1.97)
F-10= 14.775
F= 10+14.775
F = 24.775N
Hence the greatest possible magnitude of the other force is 24.775N
If a 15kg mass weighs 372 N on Jupiter, what is Jupiter's gravitational acceleration?
Answer:
The mass of Jupiter is 1.9 x 1027 kg. It is hard to fully understand a number that large, so here are a few comparisons to help. It would take 318 times Earth's mass to equal Jupiter's.
Explanation:
A rope 6m long is fixed at one end; the other end is attached to a light string so that it is free to move. The speed of waves on the rope is 18 m/s. The frequency of the second harmonic is
Given :
A rope 6m long is fixed at one end, the other end is attached to a light string so that it is free to move.
The speed of waves on the rope is 18 m/s.
To Find :
The frequency of the second harmonic.
Solution :
We know, for second harmonic wave :
Wavelength = Length of rope
[tex]\lambda = L\\\\\lambda = 6 \ m[/tex]
Now, we know frequency is given by :
[tex]Frequency = \dfrac{Speed}{Wavelenght}\\\\f = \dfrac{18 \ m/s}{6\ m}\\\\f = 3 \ s^{-1}[/tex]
Therefore, the frequency of the second harmonic is 3 s⁻¹.
If you travel from Tucson to Argentina, you will see some different constellations in the night sky. true or false
Answer:
its true!!
Explanation: have a nice day !!
What is the acceleration aaa of the refrigerator 4 ss after the person begins pushing on it with a force of 400 NN
Answer:
2 ms^2
Explanation:
Given that the mass of the refrigerator is 200Kg
The net force acting on the refrigerator is 400N
The time takes is 4s
From Newtons's second law of motion;
F =ma
a = F/m
a = 400/200
a = 2 ms^2
This is a constant acceleration
where V is the voltage in volts, I is the current in amperes, and R is the resistance in ohms. Assume that, as the battery wears out, the voltage decreases at 0.03 volts per second and, as the resistor heats up, the resistance is increasing at 0.02 ohms per second. When the resistance is 100 ohms and the current is 0.02 amperes, at what rate is the current changing
Answer:
[tex]\frac{dI}{dt} =-3.04*10^-^4amps/sec[/tex]
Explanation:
From the question we are told that
Voltage change [tex]\frac{dv}{dt}=-0.03volts/sec[/tex]
Resistance change [tex]\frac{dR}{dt}=0.02ohms/sec[/tex]
Resistance [tex]R=100[/tex]
Current [tex]I=0.02[/tex]
Generally the equation for ohms law is mathematically represented as
[tex]V=IR[/tex]
Therefore
[tex]\frac{dv}{dt} =R\frac{dI}{dt} +I\frac{dR}{dt}[/tex]
[tex]\frac{dv}{dt} =R\frac{dI}{dt} +I\frac{dR}{dt}[/tex]
Resolving the Rate of current changing [tex]\frac{dI}{dt}[/tex] as subject of formula
[tex]\frac{dv}{dt} =R\frac{dI}{dt} +I\frac{dR}{dt}[/tex]
[tex]R\frac{dI}{dt} =\frac{dv}{dt} -I\frac{dR}{dt}[/tex]
[tex]\frac{dI}{dt} =\frac{1}{R} (\frac{dv}{dt} -I\frac{dR}{dt})[/tex]
Therefore
[tex]\frac{dI}{dt} =\frac{(-0.03) -(0.02)(0.02)}{100}[/tex]
[tex]\frac{dI}{dt} =-3.04*10^-^4amps/sec[/tex]
Therefore the current decreases at a rate
[tex]\frac{dI}{dt} =3.04*10^-^4amps/sec[/tex]
HELP CORRECTLY FOR BRAINLIEST!!!!! According to the graph, what type of relationship exists between
time and temperature?
50.0
40.0
С
trend line
30.0
Temperature (°C)
20.0
10.0
B
0.0
0
10
40
50
60
20
30
Time (minutes)
O direct
O inverse
O codependent
O equivalent
Answer: direct
Explanation: as the time (independent variable) goes on the temperature drops, it’s cooling down because time is passing by
help!!!
middle school physics also please explain :)
Answer:
hope its helps
good luck
Answer:
0.1 cm/s
Explanation:
16 min 40 second = 1000 sec
1m = 100cm
100/1000 = 0.1 (speed = distance/time)
A man pushes a 10 kg box a distance of 5 m for 3 hours. How much work
did the man complete?*
Answer:
alot
Explanation:
cuz he pushed for a long time
help mmmemememeeee I'M BEING TIMED
Answer:
it's c. or A. not b.
Explanation:
.................
A 20 kg sled is pulled up a 10m tall hill. What work is done against gravity?
Answer:
1962
Explanation:
w = f × d
= 20×9.81 × 10
= 1962
When you graph displacement vs. time, velocity is represented by
A. the x-intercept of the graph
B. the y-intercept of the graph
C. the slope of the graph
D. the curve of the graph
A 1.6-cm-wide diffraction grating has 1000 slits. It is illuminated by light of wavelength 530 nm. What are the angles of the first two diffraction orders?
Answer:
The answer is "[tex]1.96^{\circ} \ and \ 3.94^{\circ}[/tex]"
Explanation:
[tex]N= 1000 \frac{slit}{cm} \\\\\lambda=550 nm\ \ =550 \times 10^{-9} \ m\\\\width=1.6 \ cm[/tex]
We can find the distance between any two adjacent slits by using
[tex]\to d= \frac{1.6}{N}\\\\ \therefore\\ \to d= \frac{1.6}{1000} \ cm= 1.6 \times 10^{-5} m\\[/tex]
We know that the angle of the mth fringe is given by
[tex]\sin \theta_m = \frac{m\lambda}{d}\\\\ \sin \theta_1 = \frac{1\lambda}{d}\\\\\theta_1 = \sin^{-1} \frac{1\lambda}{d}\\\\\theta_1 = \sin^{-1}(\frac{1 \times 550 \times 10^{-9}}{1.6 \times 10^{-5}})\\\\ \theta_1=1.96^{\circ}\\\\[/tex]
Using the same way:
[tex]\sin \theta_2 = \frac{2\times \lambda}{d}\\\\\theta_2 = \sin^{-1} \frac{2\times \lambda}{d}\\\\\theta_2 = \sin^{-1}(\frac{2 \times 550 \times 10^{-9}}{1.6 \times 10^{-5}})\\\\\theta_2=3.94^{\circ}\\\\[/tex]
By using the Huygens formula, the angles of the first two orders are 4 degrees and 8 degrees approximately.
Given that a 1.6cm wide diffraction grating has 1000 slits.
The slit spacing = (1.6 x [tex]10^{-2}[/tex]) / 1000
The slit spacing = 1.6 x [tex]1.6^{-5}[/tex]
Also, it is given that It is illuminated by light of wavelength 530 nm
Sin∅ = nλ/d
When n = 1
Sin∅ = 530 x [tex]10^{-9}[/tex]/1.6 x [tex]10^{-5}[/tex]
Sin∅ = 0.033125
∅ = [tex]Sin^{-1}[/tex] ( 0.033125)
∅ = 1.898 x 2
The angle of the first order = 2∅
2∅ = 4 degrees approximately
When n = 2
Sin∅ = nλ/d
Sin∅ = 2 x 530 x [tex]10^{-9}[/tex]/1.6 x [tex]10^{-5}[/tex]
Sin∅ = 0.06625
∅ = [tex]Sin^{-1}[/tex] ( 0.06625)
The angle of the second order = 2∅
2∅ = 3.7986 x 2
2∅ = 8 degrees approximately
Therefore, the angles of the first two orders are 4 degrees and 8 degrees approximately.
Learn more here: https://brainly.com/question/13902808
A person is standing on and facing the front of a stationary skateboard while holding a construction brick. The mass of the person is 67.0 kg, the mass of the skateboard is 4.10 kg, and the mass of the brick is 2.50 kg. If the person throws the brick forward (in the direction they are facing) with a speed of 23.0 m/s relative to the skateboard and we ignore friction, determine the recoil speed of the person and the skateboard, relative to the ground.
Answer:
v₁ = -0.8087 m / s
Explanation:
To solve this problem we can use the conservation of momentum, for this we define a system formed by the man, the skateboard and the brick, therefore the force during the separation is internal and the momentum is conserved
Initial instant. When they are united
p₀ = 0
Final moment. After throwing the brick
[tex]p_{f}[/tex] = (m_man + m_skate) v1 + m_brick v2
the moment is preserved
p₀ = p_{f}
0 = (m_man + m_skate) v₁ + m_brick v₂
v₁ = - [tex]\frac{ m_{brick} }{m_{man} + m_{skate} } v_{2}[/tex]
the negative sign indicates that the two speeds are in the opposite direction
let's calculate
v₁ = - [tex]\frac{2.5}{67 + 4.10} 23.0[/tex]
v₁ = -0.8087 m / s
honey solidifies from the bottom whereas water from the top. Why?
Answer:
it is due to anamolous expansion of water as water cools from 4dg.c to 0dg.c. it expand making ice lighter than water to float
ASAP what causes the earth to orbit just like Mars
Answer:
Like all the planets in our solar system, Earth and Mars orbit the sun. But Earth is closer to the sun, and therefore races along its orbit more quickly. Earth makes two trips around the sun in about the same amount of time that Mars takes to make one trip.
when a substance such as ice melts, its temperature increases. desrcibe what happens to the arrangment of water molecules as the temperature increases
Explanation:
The water molecules begins to leave their fixed position and begins to move as the temperature increases.
When ice melts, it undergoes a state change from solid to liquid and with increasing temperature becomes a gas.
The basis for this is the increasing movement of the molecules of the water as it transitions from one phase to another. In the ice, the molecules are locked and fixed in the latticeAs the temperature increases, the average kinetic energy of the particles rises. This makes the structure of the ice to collapse and forms liquids. By the virtue of this, they flow and move over one another With increasing temperature, the bonds are broken and vapor formsWhat is the density of an object whose volume is 100 cubic centimeters that has a mass of 100 grams?
Answer:
search omni calculator and these problems can be solved easily:) hope this helps! 62.43
Answer:
1 g/cm3
Explanation:
just had it and this was the answer
How is property belonging to individuals protected under the Fifth Amendment?
By preventing the government from taking property without fair payment.
By preventing a police search of private property without a warrant
By prohibiting the quartering of soldiers without permission
By guaranteeing every citizen the right to apply for a home loan
Answer:
By preventing the government from taking property without fair payment.
Explanation:
Answer 1
Please mark me as brilliant and thank you
Answer:
this is under the wrong section
A sample contains 10g of radioactive isotope. How much radioactive isotope will remain in the sample after 3 half-lives?
Answer:
After 1 half-life (500 years), 500 g of the parent isotope will remain. After 2 half-lives (1000 years), 250 g of the parent isotope will remain. After 3 half-lives (1500 years), 125 g of the parent isotope will remain. After 4 half-lives (2000 years), 62.5 g of the parent isotope will remain.
Explanation:
consider two point charges of 1.60uC and -22.25uC. Determine the magnitude of the force between the two charges when placed 6.50cm apart.
Answer:
[tex]F$\approx$76[/tex]
Explanation:
From the question we are told that
Point charges [tex]q_1=1.60uC[/tex]
[tex]q_2=-22.25uC[/tex]
Displacement [tex]d=6.50cm=>0.065m[/tex]
Generally the equation for Coulomb's law is Mathematically given as
[tex]F=\frac{k*q_1*q_2}{r^2}[/tex]
Therefore
[tex]F=\frac{9*10^9*-22.25*10^-^6*(1.60)*10^-^6}{(6.50*10^-^2)^2}[/tex]
[tex]F=-75.83431953[/tex]
[tex]F$\approx$-76[/tex]
with -(negative) showing form of force Magnitude => [tex]F$\approx$76[/tex]
a 10.0 kg mass is at the origin. A 20.0 kg mass is 0.500 m to the left of it, and a 30.0 kg mass is 1.25 m to the right of it, what is the net gravitational force on the 10.o kg mass?
? x 10^-8 n
Explanation:
100N please mark me brainliest