Answer:
d = 343 m
Explanation:
Given that,
You notice that an echo took 2 seconds before you heard the echo of your yell.
We need to find that how far away is the canyon wall that reflected your yell. It means we need to find the distance.
The distance covered by an object is given by :
d = v × t
v is speed of sound in air, v = 343 m/s
The sound took 1 s to reach the wall and 1 s back to you.
It means that,
d = 343 × 1
d = 343 m
So, canyon will reflect your yell at a distance of 343 m
A gauge is reading the pressure at the bottom of a river, at a depth of 6 m. Would the reading be greater or smaller than the reading at the bottom of a lake at the same depth? You must provide a clear explanation for full credit.
Answer:
The pressure at the bottom of the river is less than that at the bottom of the lake.
Explanation:
From Bernoulli's equation, the pressure difference is given by
ΔP = ρgΔh + ρ(v₂² - v₁²)/2 where ρ = density of water, g = acceleration due to gravity, Δh = depth, v₁ = velocity at top, v₂ = velocity at bottom
For the lake, v₁ = v₂, since the velocity at the top and bottom are the same. So,
ΔP₁ = ρgΔh + ρ(v₁² - v₁²)/2 = ρgΔh + 0 = ρgΔh
P₂ - P₁ = ρgΔh
P₂ = P₁ + ρgΔh
For the river, v₁ < v₂, since the velocity at the top of the river is greater than at the bottom.
So,
ΔP₂ = ρgΔh + ρ(v₂² - v₁²)/2.
Since v₁ < v₂, ρ(v₂² - v₁²)/2 will be negative,
So,
ΔP₂ = ρgΔh - ρ(v₂² - v₁²)/2.
Since ρ(v₂² - v₁²)/2 is negative, making ΔP less than that in the lake.
So, ΔP₂ = ΔP₁ - ρ(v₂² - v₁²)/2.
ΔP₂ = P₃ - P₁
P₃ - P₁ = P₂ - P₁ - ρ(v₂² - v₁²)/2.
P₃ = P₂ - ρ(v₂² - v₁²)/2.
where P₃ = pressure at bottom of the river and P₂ = pressure at bottom of the lake and P₁ = atmospheric pressure at top of river and lake respectively.
Since the factor ρ(v₂² - v₁²)/2 is removed from the pressure at the bottom of the lake, the pressure at the bottom of the river is therefore less than that at the bottom of the lake.
Students create a standing wave
with three loops on a slinky 3.75 m
long. They time 20 oscillations in
6.73 s. What is the wavelength of
the standing wave?
(Unit = m)
Explanation:
Given that,
Number of loops are 3
Length of slinky is 3.75 m
They time 20 oscillations in 6.73 s.
We need to find the wavelength of the standing wave.
For 3 loops, [tex]L=\dfrac{3\lambda}{2}[/tex]
Here, [tex]\lambda[/tex] is the wavelength of the standing wave
So,
[tex]\lambda=\dfrac{2L}{3}\\\\\lambda=\dfrac{2\times 3.75}{3}\\\\\lambda=2.5\ m[/tex]
So, the wavelength of the standing wave is 2.5 m.
You have a reservoir held at a constant temperature of –30°C. You add 400 J of heat to the reservoir. If you have another reservoir at 0°C, how much heat must you add to it so that both reservoirs have the same increase in entropy?
Answer:
449.38 J
Explanation:
ΔS = ΔQ/T
Where ΔS = entropy change
Q = quantity of heat
T = temperature
First reservoir :
T = –30°C = - 30 + 273 = 243K
Q = 400 J
Second reservoir :
T = 0°C = 273K
Q =?
To have same increase in entropy for both reservoirs :
Q/T of first reservoir = Q/T of second reservoir
400/243 = Q/273
243 * Q = 400 * 273
Q = (400 * 273) / 243
Q = 109,200 / 243
Q = 449.38271
Q = 449.38 J
Distance travelled by a free falling object in the first second is: a) 4.9m b) 9.8m c) 19.6m d) 10m
In free fall
[tex]\boxed{\sf s=-\dfrac{1}{2}gt^2}[/tex]
[tex]\\ \sf\longmapsto s=-\dfrac{1}{2}\times 9.8(1)^2[/tex]
[tex]\\ \sf\longmapsto s=-4.9(1)[/tex]
[tex]\\ \sf\longmapsto s=-4.9m[/tex]
Take it positive[tex]\\ \sf\longmapsto s=4.9m[/tex]
Option a is correct7. Describe about the difficultites that would arise due to lack of non-uniformity in measurement.
Answer:
Many difficulties would arise if there was a lack of uniformity in the measurement of various weights and measures between business, industry, individuals and countries. The biggest implications for a lack of uniformity are in health and safety, equity and sustainability.
Explanation:
palike nlng po
explain radiation and which is the hotest source in the world
Ramsar has the highest level of natural radiation in the world.
Hot springs located in the Arkaroola Wilderness Sanctuary in Southern Australia are also credited with higher than normal radiation levels, due to spring water coming in contact with rocks rich in uranium and radon.
what type of image is formed by a lens if m = -0.87
A. The image is larger than the object and the image is real
B. The image is smaller than the object and the object is real
C. The image is larger than the object and is virtual
D. The image is smaller than the object and is virtual
Answer:
B.
Explanation:
as there is a '-' sign before the magnification value, it forms a real image.
so the last two options get cancelled.
as the value of magnification is 0.87 ie. lesser than 1, we can say that the image is smaller.
The type of image is formed by a lens if m = -0.87 would be smaller than the object and the object is real
What is a lens?A lens is a transmissive optical tool that employs refraction to focus or disperse a light beam. The power of the lens is expressed in the dioptre which is the reciprocal of the focal length of the lens.
The image formation through the lens is calculated with the help of the lens formula given as follows
1/f = 1/v - 1/u
where f is the focal length of the lens
u is the distance of the object from the lens
v is the distance of the image formed from the
magnification (m) = size of image /size of the object
As given in the problem image is formed by a lens if m = -0.87
Thus, the negative sign represents that the image formed by the object is real, and the magnitude of the magnification is less than 1 this represents that size of the image is smaller than the size of the object.
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A drone has been designed that can do monitoring and surveillance at considerable heights due to its light weight of 0.800 kg. For this purpose, they are doing a test to determine its maximum height and they make it start in a vertical direction, using its thrusters it manages to achieve a thrust of 35.0 N during the first 6.00 s. until the battery runs out. What was the maximum height that the drone reached?
Answer:
2660 m
Explanation:
Sum of the forces in the first 6.00 s:
∑F = ma
F − mg = ma
35.0 N − (0.800 kg) (10 m/s²) = (0.800 kg) a
a = 33.75 m/s²
The height it reaches during this time is:
Δy = v₀ t + ½ at²
Δy = (0 m/s) (6.00 s) + ½ (33.75 m/s²) (6.00 s)²
Δy = 607.5 m
The velocity it reaches is:
v = at + v₀
v = (33.75 m/s²) (6.00 s) + 0 m/s
v = 202.5 m/s
After the battery runs out, the drone is in free fall. At the highest point, the velocity is 0. The height at this point is:
v² = v₀² + 2aΔy
(0 m/s)² = (202.5 m/s)² + 2 (-10 m/s²) (h − 607.5)
h ≈ 2660 m
i) A 100 W and 60 W bulb are joined in series and connected to the mains. Which bulb will glow brighter? Why? ii) A 100 W and a 60 W bulb are joined in parallel to the mains. Which bulb will glow brighter? Why?
Answer:
i) 60 W
ii) 100 W
Explanation:
In each case, the bulb that dissipates the most power is the bulb that glows brighter. Power is voltage times current (P = VI). Using Ohm's law, we can rewrite this as P = I²R or P = V²/R.
Bulbs are rated at a certain power for a certain voltage. P = V²/R, so the bulb with the lower resistance will have the higher power rating. Therefore, the 100 W bulb has a lower resistance than the 60 W bulb.
i) They are in series, so they have the same current. P = I²R, so the bulb with the higher resistance will glow brighter. That's the 60 W bulb.
ii) They are in parallel, so they have the same voltage. P = V²/R, so the bulb with the lower resistance will glow brighter. That's the 100 W bulb.
to what temperature must a given mass of nitrogen at zero degrees be heated so both its volume and pressure will be doubled
Answer:
0 degrees Celsius is 273 degrees Kelvin. As both pressure and volume are proportional to absolute temperature, in order to double both you would need to quadruple the temperature. I.e. 273 X 4 = 1092 Kelvin = 819 Celsius
Explanation:
Because the neutron has no charge, its mass must be found in some way other than by using a mass spectrometer. When a neutron and a proton meet (assume both to be almost stationary), they combine and form a deuteron, emitting a gamma ray whose energy is 2.2233 MeV. The masses of the proton and the deuteron are 1.007 276 467 u and 2.013 553 212 u, respectively. Based on this data, what is the mass of the neutron
Answer:
Explanation:
Energy of gamma ray = 2.2233 MeV
Let mass of neutron be n amu
mass defect of deuteron = 2.013553212 - ( 1.007 276 467 + n ) u .
in terms of energy this mass defect will be equal to energy of gamma ray
1 amu = 931 MeV
931 [ 2.013553212 - ( 1.007 276 467 + n ) ] = 2.2233
( 1.007 276 467 + n ) - 2.013553212 = .00238807733
n = 1.008664822 amu
so mass of neutron = 1.008664822 amu
1. A physical quantity P is related to four observables a, b and c as follows: P= (a3b 2 /c4 ) The percentage errors of measurements in a, b and c are 1%, 4% and 2% respectively. What is the percentage error in quantity P?
Answer:
The percentage error in quantity P is 19%.
Explanation:
It is given that,
A physical quantity P is related to four observables a, b and c as follows:
[tex]P=\dfrac{a^3b^2}{c^4}[/tex]
The percentage errors of measurements in a, b and c are 1%, 4% and 2% respectively.
We need to find the percentage error in quantity P. It is given by :
[tex]\dfrac{\Delta P}{P}\times 100=(3\times \dfrac{\Delta a}{a}+2\times \dfrac{\Delta b}{b}+4\times \dfrac{\Delta c}{c})\\\\=3\times 1+2\times 4+4\times 2\\\\\dfrac{\Delta P}{P}\times 100=19\%[/tex]
So, the percentage error in quantity P is 19%.
Which element has atoms with valence electrons in a higher energy level than those of calcium (Ca)?
(1 point)
oxygen (O)
lithium (Li)
bromine (Br)
cesium (Cs)
Lithium element contains one electron therefore valence electron will be one.
The highest level of energy is due to valence electrons which are available to the atom.
The calcium has 2 valence electrons which has electrons with high energy.
These energy will be used by the electron during the chemical reaction, and they will either lose or gain valence electron.
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Answer:
calcium
Explanation:
2 electron
The ways to measure the mass and volume of irregular object
Answer:
When we have irregular objects, it may become very hard to calculate the volume of the object, as we actually can not use any simple equation to find it.
The mass is less tricky, just find a scale and wheight it, now we know the mass of the irregular object.
One way to measure the volume of the object is using water... how we do it?
Get some recipient with water, measure the height of the water.
Introduce your object into the water and totally submerge it, now the level of the water will rise. This is because as you introduce the object under the water, you are displacing up a given volume of water that has the same volume as the irregular object.
Now that you know the height of the water before and after you put your object, you can easily calculate the volume of water displaced, and that will be the volume of the object (the tricky part may be totally submerging the object if, for example, is wood and it floats, here you can use a thin wire to push it down but it will affect a little bit the measures.)
what does the area under a distance-time graph signify?
Explanation:
The area under a displacement vs time graph is the absement.
Which best describes what happens if two waves meet and build on each other? constructive interference destructive interference reflection absorption
Answer:
Which best describes what happens if two waves meet and build on each other?
constructive interferencedestructive interference
reflection
absorption
Explanation:
When two waves meet in phase they will overlap together and form a constructive interference. The resultant amplitude of the waves will be greater than that of individual waves.
What is interference ?A wave of greater, lower, or the same amplitude is created when two waves merge through interference by combining their displacements at all points in space and time.
The interaction of waves that are coherent or correlated with one another, either because they originate from the same source or because their frequencies are similar or almost identical, leads to both constructive and destructive interference.
All sorts of waves, including light, radio, acoustic, surface water waves, gravity waves, and matter waves, can exhibit interference effects. In constructive interference, the waves are in single phase forms a resultant wave with higher amplitude.
When waves from out of phase meets, the resultant wave will have an amplitude less than the individual amplitudes. Here, the waves are meet in phase and build on each is constructive interference.
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công thức lực đàn hồi
Answer:
gagaggagagagagooo
Explanation:
gagagagagagagagaoooo
When the hydraulic conductivity Ks = 10 mm/hr; effective matrix potential Ns = 20 mm, and rainfall intensity I = 30 mm/hr , determine the amount of runoff generated when the runoff rate reaches 15 mm/hr?( 2.7 mm or 0.21 mm or 18 mm or 0.67 mm)
Answer:
[tex]t = 0.75 \ hr = 0.75 *60 = 45 \ minutes[/tex]
Explanation:
From the question we are told that
The hydraulic conductivity is [tex]Ks = 10\ mm/hr[/tex]
The effective matrix potential [tex]Ns = 20 \ mm[/tex]
The intensity of rainfall is [tex]I = 30 \ mm/hr[/tex]
The runoff rate [tex]R = 15 \ mm/hr[/tex]
Generally the run off rate is mathematically represented as
[tex]R = (I - Ks) t[/tex]
Here t is the amount of runoff generated
=> [tex]15 = (30 - 10) t[/tex]
=> [tex]t = 0.75 \ hr[/tex]
converting to minutes
[tex]t = 0.75 \ hr = 0.75 *60 = 45 \ minutes[/tex]
Describe the following as a (a) distance (b) speed (c) acceleration (d) force
6. Force
7 speed
8 distance
9 acceleration
If a suitcase has a mass of 20 kg, what is the force of gravity acting on it?
Explanation:
Assuming the suitcase is near the surface of the earth, g = 9.8 m/s².
F = ma
F = (20 kg) (9.8 m/s²)
F = 196 N
Forensic toxicologist analyze and identify drugs that are confiscated from criminals
True
False
Distinguish between concave mirror and convex mirror
Answer:
Concave mirror makes someone looking at it look dwarf or short, while convex mirror stretches the person making the person look weird.
solve 1 for x if a=-9.8, v=2.7, and t= 35
Answer:
6097 = x
Explanation:
x = VT + at²/2
x= 2.7 * 35 + 9.8 * (35)²/2
x=6097
2. State Newton's third law of motion.
Answer:
Action and reaction are equal but act in opposite directions
Answer:
Newton’s third law of motion states that “ for every action there is always an equal and opposite reaction.”
Explanation:
If body A exerts a force on body B, then body B will exert an equal and opposite force on body A. It is also called action reaction force. They have equal magnitude but are opposite in direction.
prove p=f/a science chapter pressure
Explanation:
Let 'F' be force acting perpendicularly, 'A' be the area and 'P' be the pressure exerted.
Then,
Pressure is directly proportional to the the force acting perpendicularly i.e.
P ∝ F ............. (i)
Pressure is inversely proportional to the area on which force acts i.e.
P ∝ 1/A ........... (ii)
Combining equations (i) and (ii),
P ∝ F/A
or, P = K × F/A [where K is a constant]
If F is 1N, A is 1m² and P is 1 N/m², then K is 1.
So, P = F/A proved...
When astronauts are on spacewalks outside of the International Space Station, they must use a communication system with radio waves to be able to talk to each other. Explain why focusing on the difference between sound and light waves
Light waves are electromagnetic waves while sound waves are mechanical waves. Light waves are transverse while sound waves are longitudinal. Light waves can travel in vacuum. Sound waves require a material medium to travel, and hence, cannot travel in vacuum.
They make use of radio waves. Radio waves signal are sent their headsets that in turn translates the signal in the form of sound. While communicating with people on Earth – the radio waves are transmitted which in turn are transformed to sound wave by a radio set. Radio waves comes from the light spectrum called Electromagnetic Spectrum and thus they are light waves. Unlike sound, light waves doesn’t need a medium to travel and it is for this reason that the sun ray travels through space to the Earth
We all know who was the first man that landed on moon? But were the first words ever heard in space?
It was the announcement of landing that was said by Neil Armstrong: “Lunar Module has landed on moon”
Answer: Light waves are electromagnetic waves while sound waves are mechanical waves. Light waves are transverse while sound waves are longitudinal. Light waves can travel in vacuum. Sound waves require a material medium to travel, and hence, cannot travel in vacuum.
Explanation:
The moving bicycle moves for sometime even after stopping the paddling.why
Answer:
when you are paddling the push carry on when you paddle the hard put on the push.
Answer:
Because of inertia
Explanation:
As stated in Newton first law "An object at rest will stay at rest, an object in motion will stay in motion unless it is acted upon by a force."
For an example:
If you have a drink without a lid in a car and a car suddently the car stop, u will automatically try to catch the drink preventing it from spilling. This is because that the drink that was in motion with the car want to stay in motion, but when the car stop, the drink still wanna be in motion, that's why it will be flying off and spill if u don't catch it.
Back to the question:
if a bicyccle is in motion, it will wants to be in motion untill a force act upon it, let's say a bump or fricition.
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Can you solve this question please help me with this
Answer:
Explanation:
The velocity ratio of a wheel and axle is the ratio of the radius (R) of the wheel to the radius (r) of the axle. It is expressed as;
VR = R/r
Since radius = diameter/2
VR = (D/2)/(d/2)
VR = D/d
D is the diameter of the wheel and 'd' is the diameter of the axle.
Given VR = 3 and d = 5cm
3 = D/5
D = 15 cm
If the diameter of the wheel is 15cm, the radius of the wheel will be 15/2 = 7.5cm.
b) Workdone by the load = Load * distance moved by load
Given load = 60kg
Distance moved by load = 2π*radius of axle
Distance moved by load = 2π(0.025) = 0.157
workdone by load = 60* 0.157 = 9.42J
Effort = Workdone by load/distance moved by the wheel
Effort = 9.42/2π(0.075)
Effort = 9.42/0.471
Effort = 20kg
Hence the effort applied is 20kg
c) MA = Load/Effort
MA = 60/20
MA = 3
d) Efficiency = MA/VR * 100%
Efficiency = 3/3 * 100%
Efficiency = 100%
a boy jumps out of the bus . there is danger for him to fall:
a) towards moving bus
b)away from moving bus
c) in the directioin of motion
d) opposite to the direction of motion
Answer:
(B)
Explanation:
the boy will fall away from the bus if the bus is moving.
A 92.45 kg baseball player slides to a stop at third base. The coefficient of kinetic friction between the player and the ground is
0.68. Her speed at the start of the slide is 6.87 m/s.
(a) Calculate her acceleration during the slide.
(b) How long (in time) does she slide until she stops?
a) Her acceleration during the slide is -6.67 m/s².
b) She slides 1.03 seconds until she stops.
a) We can find her acceleration during the slide with Newton's second law:
[tex] F = ma [/tex]
Where:
F: is the force
m: is the mass = 92.45 kg
a: is the acceleration =?
The force acting on the baseball player is equal to the friction force ([tex]F_{\mu}[/tex]), and it is negative because it is in the opposite direction to the motion:
[tex] -\mu N = ma [/tex]
[tex] -\mu mg = ma [/tex]
[tex] a = -\mu g [/tex]
Where:
N: is the normal force = mg
μ: is the coefficient of kinetic firction = 0.68
g: is the acceleration due to gravity = 9.81 m/s²
Hence, her acceleration during the slide is:
[tex] a = -0.68*9.81 m/s^{2} = -6.67 m/s^{2} [/tex]
b) We can calculate how long does she slide until she stops with the following kinematic equation:
[tex] v_{f} = v_{0} + at [/tex]
Where:
[tex] v_{f} [/tex]: is the final speed = 0 (when she stops)
[tex] v_{0} [/tex]: is the initial speed = 6.87 m/s
t: is the time =?
Then, the time is:
[tex] t = -\frac{v_{0}}{a} = -\frac{6.87 m/s}{-6.67 m/s^{2}} = 1.03 s [/tex]
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