Answer:
True
Explanation:
This is in fact what the Archimedes principle states, and what he used in the famous anecdote about finding if the crown of the King was really made of gold.
If you look at faint stars, you can see them more easily on the edges of your vision than if you try to look directly at them. Why is this true?
Answer:
The retina comprises of rod and cone cells . The rod cells are responsible for black and white vision and require low light levels while the cone cells are responsible for color vision and require good/high light levels for better functioning.
When faint stars are looked at on the edges of the vision it allows more light from faint objects to strike the rod cells which then becomes more visible.
A 2.00 m long string transmits
waves at 12.9 m/s. At what
frequency will it create standing
waves with 3 loops?
(Unit = Hz)
Answer:
The frequency at which the string will create a standing wave be with three loops is 8.6 Hz
Explanation:
The speed of the of the wave, v = 12.9 m/s
The number of loops of the standing wave = 3 loops
The length of the string = 2.00 m
Given that one loo = half of the wavelength, we have;
Three loops = 3 × half = One and half wavelength = 1.5·λ
The frequency of a wave = f = v/λ
Therefore, we have;
The frequency, f = 12.9/1.5 = 8.6 Hz
The frequency at which the string will create a standing wave be with three loops = 8.6 Hz.
Answer:
9.675
Explanation:
got it right on acellus
Guys, can you please answer these three questions. I'm having trouble doing them.
Answer:
17) a) 30 kg·m/s
b) 30 kg·m/s
c) 0.3 m/s.
18) 2.4 m/s
19) 360,000 N
The different make of car is safer because the force acting on it is 28,800 N, resulting much less impact
Explanation:
17) By conservation of linear momentum principle, we have;
m₁·v₁ + m₂·v₂ = m₁·v₁' + m₂·v₂'
Where;
m₁ = The mass of the astronaut = 100 kg
v₁ = The initial velocity of the astronaut = 0 m/s
m₂ = The mass of the equipment box = 2.5 kg
v₂ = The initial velocity of the equipment box = 0 m/s
v₁' = The final velocity of the astronaut
v₂' = The final velocity of the equipment box = 12 m/s
The final momentum of the equipment box = Mass of the equipment box × Final velocity
a) The final momentum of the equipment box = 2.5 kg × 12 m/s = 30 kg·m/s
b) Given that the box and the astronaut will move in opposite directions, we have;
m₁·0 + m₂·0 = -m₁·v₁' + m₂·v₂'
m₁·v₁' = m₂·v₂'
Therefore, the momentum of the astronaut will be equal to the momentum of the equipment box = 30 kg·m/s
c) The velocity of the astronaut is given by th following relation;
100×0 + 2.5×0 = -100×v₁' + 2.5×12
100×v₁' = 2.5×12
v₁' = 2.5×12/100 = 30/100 = 0.3 m/s
The final velocity of the astronaut = 0.3 m/s.
18) By conservation of linear momentum principle, we have;
m₁·v₁ + m₂·v₂ = m₁·v₁' + m₂·v₂'
Where;
m₁ = The mass of the railway truck= 4000 kg
v₁ = The initial velocity of the railway truck= 8 m/s
m₂ = The mass of the stationary truck = 6000 kg
v₂ = The initial velocity of the stationary truck = 0 m/s
v₁' = The velocity of the two trucks immediately after collision
Therefore, we have;
4000 kg × 6 m/s + 6000 × 0 = (6000 + 4000) × v₁' = 10,000·v₁'
24,000 kg·m/s = 10,000·v₁'
v₁' = 24,000/10,000 = 2.4 m/s
The velocity of the two trucks immediately after collision is = 2.4 m/s
19) The change in kinetic energy of the car due to the collision = 1/2·m·(v₂² - v₁²)
The initial velocity of the car, v₁ = 12 m/s
The final velocity, v₂ = 0 m/s
The mass of the car, m= 600 kg
The time in which the car is brought to rest = 2 seconds
Initial time at point of collision, t₁ = 0 s
Time after collision, t₂ = 0.02 s
By Newton's second law of motion, we have
The force F acting on the car = Rate of change in momentum produced by the force
F = m × dv/dt
Force = m × (v₂ - v₁)/(t₂ - t₁) = 600×(0-12)/(0.02 - 0) = -360,000 kg·m/s²
The force acting on the car is equal and opposite to the force of the car = 360,000 N
b) For the different make of the car, we have;
m × (v₂ - v₁)/(t₂ - t₁) = 600×(0-12)/(0.25 - 0) = -28,800 kg·m/s². = -28,800 N
Therefore, the different make of car is safer because the force acting on it is 28,800 N, resulting much less impact.
Question 2 of 10
Which of the following is an Sl unit?
A. Foot
B. Inch
C. Meter
D. Mile
SUBMIT
Answer:
C. Meter
Explanation:
The International System of Unit (SI) is gotten from the french word Systeme international is a modern form of metric measurement. It is the system of measurement that is universally accepted. It is from this SI units that all other system of units are derived. There are seven basic SI units which are:
1) Length in Meter (m)
2) Time in Seconds (s)
3) Amount of Substance in mole (m)
4) Electric current in ampere (A)
5) Temperature in kelvin (k)
6) Luminous intensity in candela (cd)
7) Mass in kilogram (kg)
Which statement best describes semi-conductors? Lack free electrons that can move to other atoms Electrons within their atoms are strongly held by the nuclei Most electrons within their atoms are paired Electricity can flow through it under special conditions
Answer:
Option D (Electricity can flow through it under special conditions ) seems to be the correct choice.
Explanation:
A semiconductor has become a crystal substance with improved electrochemical properties although the temperature is increased. That would be to say, it often functions as an insulating material rather than as a conductor or a circuit. Chemical solvents could perhaps greatly enhance its conducting capacity.Other options that are provided are not related to the given theory. So that the above would be the correct choice.
Statement "Lack free electrons that can move to other atoms " describe semi-conductor.
Properties of Semiconductor:A semiconductor is a type of crystalline solid that is halfway between a conductor and an insulator in terms of electrical conductivity. A semiconductor is conducting in nature because it has free electrons and holes.So that, Lack free electrons that can move to other atoms.Learn more about the Semiconductor here:
https://brainly.com/question/1918629
An object is placed 10 cm in front of a diverging mirror. What is the focal length of the mirror if the image appears 2 cm behind the mirror?
Answer:
the focal length of the mirror is : [tex]f=-2.5\,\,cm[/tex]
Explanation:
Use the formula for the formation of image using a divergent mirror and recalling that the image (s') that this mirror formed is virtual, so it is entered as a negative number in the formula. Use the object position (s) as 10, the image position (s') as -2, and derive the value of the focal length:
[tex]\frac{1}{s} +\frac{1}{s'}=\frac{1}{f}\\\frac{1}{10} +\frac{1}{-2}=\frac{1}{f}\\\frac{1}{10} -\frac{1}{2}=\frac{1}{f}\\\frac{10\,f}{10} -\frac{10\,f}{2}=\frac{10\,f}{f}\\f-5\,f=10\\-4\,f=10\\f=-2.5\,\,cm[/tex]
A man of mass 75kg stands on a weighing machine in a lift. Determine the reading of the weighing machine when the lift is moving: 1. Upwards with an acceleration of 2m/s² 2. Downwards with a constant velocity of 1.5m/s 3. Downwards with an acceleration of 2.5m/s²
Explanation:
Given that,
Mass of a man, m = 75 kg
(1) We need to find the reading of the weighing machine when the lift is moving upwards with an acceleration of 2 m/s². When the lift is moving upward, reading of the weighing machine is given by :
R = m(g+a)
R = 75 (9.8+2)
R = 885 N
(2) When the lift is moving downwards with a constant velocity of 1.5m/s. It means that the lift is at rest. So, the reading is :
R = mg
R = 75 (9.8)
R = 735 N
(3) When the lift is moving downwards with an acceleration of 2.5 m/s². In this case,
R = m(g-a)
R = 75 (9.8-2.5)
R = 547.5 N
Hence, this is the required solution.
an astronaut takes a tuning fork with her to the moon she strikes it inside the cabin the cabin is normally filled with air so the humans inside the spacecraft are comfortable she also strikes it outside the spacecraft when she gets down on the surface of the moon which of the following is true about the tuning fork?
A: it does not vibrate inside the spacecraft
B: id does not vibrate on moon surface
C: it vibrations are not transmitted inside the spacecraft
D:it's vibrations are not transmitted to the moon's atmosphere
Answer:
d
Explanation:
a and b: it vibrates in both the difference is whether you hear the sound or not the lack or presence of molecules does not hinder the timing fork from vibrating but can hinder you from hearing since sound is a mechanical wave therefore require a medium bringing us to (c) these vibrations are transmitted because there is presence of a medium i.e air molecules so sound can be heard
but in (c) it is true since the vibrations are created but are not transmitted to your ears due to lack of a medium
How to find average acceleration only using displacement and time?
Answer:
Average acceleration = Displacement / (time)^2
Explanation:
The unit for acceleration is
[tex]m {s}^{ - 2} [/tex]
Displacement = m
Time = s
Hence the units of displacement and time should be manipulated to get the unit of acceleration.
You can't. You can only find average velocity.
But if you also know that initial velocity is zero ... the object started from rest ... then
Avg acceleration =
2 x displacement / time-squared
Solve for angles A-D
[tex]r=s^2/t^2[/tex] 1. If s is tripled and t stays constant, r is multiplied by... 2. If t is doubled, and s stays constant, r is multiplies by...
Answer:
9 and 4
Explanation:
The relation is:
● r = s^2 / t^2
Triplind s means multiplying it by 3. Since it's an equation we should multiply both sides by the same number
Let k be the number we should multiply by r
●k* r = (3s)^2 / t^2
●k* r = 9s^2 /t^2
We have multiplied s^2 by 9 so we should do the same for r.
k = 9
■■■■■■■■■■■■■■■■■■■■■■■■■■
Doubling t means multiplying it by 2.
Let x be the number we shoukd multiply by r.
● x* r = s^2/(2t)^2
● x*r = s^2/ 4t^2
We have multiplied t^2 by 4 so we should do the same for r.
x= 4
A skydiver falls toward the ground at a constant velocity. Which statement best applies Newton’s laws of motion to explain the skydiver’s motion? An upward force balances the downward force of gravity on the skydiver. The skydiver’s inertia is zero, which no longer allows for acceleration. An unbalanced force pulls the skydiver toward the ground. The mass of the skydiver is so great that there is no acceleration
Answer: A) an upward force balances the downward force of gravity on the skydiver
Explanation: I got it correct on my test on edge
The statement best applies Newton’s laws of motion to explain the skydiver’s motion an upward force balances the downward force of gravity on the skydiver. Thus, option A is correct.
Which statement best applies Newton’s laws of motion?
The statement that best applies Newton’s laws of motion to explain the skydiver’s motion is that an upward force balances the downward force of gravity on the skydiver. Newton's 3rd law often applies to skydiving.
When gravity is not acting upon the skydivers they would continue moving in the direction the vehicle they jumped from was moving. If no air resistance takes place, then the skydivers would still accelerating at 9.8 m/s until they hit the ground.
The skydiver after leaving the aircraft will accelerates downwards due to the force of gravity usually as there is no air resistance acting in the upwards direction, and there is a resultant force acting downwards, the skydiver will accelerates towards the ground.
Therefore, The statement best applies Newton’s laws of motion to explain the skydiver’s motion an upward force balances the downward force of gravity on the skydiver. Thus, option A is correct.
Learn more about skydiver on:
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the distance between two successive troughs of wave is 0.4m. If the frequency of the source is 825Hz, calculate the speed of the wave
Answer:
speed=330m/s
Explanation:
the speed of wave is given as
speed(meter per second) =frequency(hertz) * wavelength(meters)
so using the above formula we substitute the figures given in the question in the formula we get
speed = 0.4*825
speed =330m/s
note m/s is the si unit for speed which is read as meter per second
therefore speed =330m/s
Earth orbits 1 AU from the Sun, and the Oort cloud extends from about 10,000 to 100,000 AU from the Sun. If you represent Earth’s orbit around the Sun with a paper plate 4 inches in radius, how far away will the inner edge of the Oort Cloud be? The outer edge? Express your answers in miles.
Explanation:
Earth’s orbit around the Sun represented as :
1 AU = 4 inches
Therefore,
Inner edge of the Oort Cloud represented as :
10,000 AU = 40,000 / 63360 = 0.631 miles
Outer edge of the Oort Cloud represented as:
100,000 AU = 400,000 / 63360 = 6.31 miles
Explain the structure of a clinical thermometer
Explanation:
a clinical thermometer is a thermometer used to measure human body temperature. mostade in the 20th century are mercury-in-glass thermometer. they ate accurate and sensitive having a narrow place where the mercury level rises very fast. a kink in the tube stops the mercury level from falling on its own.
hope it helps you
Identifying Maller
In your own words, describe how matter is identified.
Answer:
Matter can be identified through its properties. One clue to helps us identify matter is magnetism. Magnetism is the ability of a material to be attracted by a magnet. Only certain materials are attracted to magnets, like iron, nickel, and cobalt.
Explanation:
we can identify matter by: physical properties and
chemical properties
what is space in detail?
Answer:
Space in the astronomy and cosmology space is 3 dimensional region and earth atmosphere end is called space.
Explanation:
Space is the everything of the top earth atmosphere moon, starts, milky way, black hole and GPS satellites an distant,space also called between stars,moon,planet.
Space is all the extends far in all directions, space is finite unbound space surface of the earth has finite are no beginning or not end.
Space contains there are three dimensions is called 3 D space,an space is to refer an interval during signal transmitted also used by the character, bytes, words and octets in digital signal.
space is that term can refer to various in science, communications and mathematics,and maintain orbits for responsible time, space is usually to begin at the lowest attitude satellites can maintain orbits.
space coordinates are uniquely define the location of any particular point and that continuum requires more than coordinates,and the number of dimensions and conventional space or digital communications during the signal represents logic is 0 words in a digital signal.
Answer answer answer it it it
Answer:
(B) Parachutes
Explanation:
Air resistance works to slow down trains and airplanes, so it isn't desirable. Air resistance also causes pendulums to slow and stop.
Parachutes need air resistance to slow a person's fall. So air resistance is desirable here.
Answer:
B i answered it it it
Explanation:
One end of a graphite rod is brought near a heat source. How does the other end of the rod eventually heat up? A. Directly from the heat source B. Vibrations from neighboring atoms C. Waves from the heat source D. Waves from neighboring atoms
Answer:
Vibrations from neighboring atoms
Explanation:
When a rod is heated, the thermal energy transferred to the molecules of the rod causes them to vibrate faster. As the molecules near the heat source vibrate faster, they eventually transfer their excess energy to neighbouring molecules which also begin to vibrate faster. This continues until heat is distributed throughout the length of the rod.
The process described above is known as heat transfer by conduction.
Se suelta un cuerpo desde la azotea de un edificio de 180m de alto. Luego de 3s se lanza verticalmente hacia abajo otro cuerpo. Si ambos llegan simultáneamente al piso, calcular la rapidez con la que fue lanzado el segundo cuerpo (g=10m/s2).
Answer:CcCcccccc
Explanation:
Rfsgqh
A small cylinder is rolled along a ruler and completes two revolutions. The circumference is the distance around the outside of a circle. What is the circumference of the cylinder? A 4.4 cm B 5.2 cm C 8.8 cm D 10.2 cm
Answer; 4.4cm
Explanation: There is a ruler upon which the cylinder start from 1.4cm and reaches 10.2cm
distance traveled =10.2-1.4=8.8
since this cylinder is small so the linear distance can be approximately taked as rotational distance(as in case of point charge) so
2x2πxr =8.8
so the circumference will be 2πr=4.4cm
A force of 20N changes the position of a body. If mass of the body is 2kg, find the acceleration produced in the body.2. A ball of mass 500g is thrown upwards with a velocity of 15m/s. Calculate its momentum at the highest point.
Explanation:
Hello there!!!
You just need to use simple formula for force and momentum,
F= m.a
and momentum (p)= m.v
where m= mass
v= velocity.
a= acceleration .
And the solutions are in pictures.
Hope it helps..
The energy change in an endothermic reaction is: A. Internal B. External C. Negative D. Positive
Answer:
Positive
Explanation:
In an endothermic reaction, the products are at a higher energy than the reactants. This means that the enthalpy change of the reaction (∆H) is positive
You are the driver of the car in the photos above. You Are traveling at 30 mph when suddenly the car goes from its position in the first photo to the position in the second photo. What is happening
Answer:
the car uses teleportation, to zip to one side of the photo, to the other
Explanation:
The motion of a particle along a straight line is described by the equation x=6+4t2 -t 4 , where x is in meter and t is in seconds. Find position, velocity, and acceleration of the object when t=2s.
Answer:
The position of the particle is 6m
The velocity of the particle is 16 m/s in negative direction
The acceleration of the object is -40 m/s²
Explanation:
Given;
motion of the particle along a straight line as x = 6 + 4t² - t⁴
The position of the object when t = 2s
x = 6 + 4(2)² - (2)⁴
x = 6 + 16 - 16
x = 6m
The velocity of the object when t = 2s
Velocity = dx/dt
dx/dt = 8t - 4t³
when t = 2s
Velocity = 8(2) - 4(2)³
Velocity = 16 - 32
Velocity = -16m/s
Velocity = 16 m/s (in negative direction)
The acceleration of the object when t = 2s
Acceleration = d²x/dt² = 8 - 12t²
Acceleration = 8 - 12 (2)²
Acceleration = -40 m/s²
1 point
40 The diagram below shows an electrical circuit made up of a cell and three loads. The
voltage established by the cell and the resistance of each load is marked on the
diagram. Select the current flowing through the 3-ohm load.
www
1 ohm
12V
2 ohms
WWW
3 ohms
www
A. 4 amps
B. 2 amps
C. 5 amps
D. 0.25 amps
SPS106 DOK 3
Answer:
Option B. 2 A.
Explanation:
The following data were obtained from the question:
Resistance 1 (R1) = 1 Ω
Resistance 2 (R2) = 2 Ω
Resistance 3 (R3) = 3 Ω
Potential difference (V) = 12 V.
Current through the 3 Ω (I3) =?
Next, we shall determine the total resistance of the circuit.
This can be obtained as follow:
Resistance 1 (R1) = 1 Ω
Resistance 2 (R2) = 2 Ω
Resistance 3 (R3) = 3 Ω
Total resistance (R) =.?
R = R1 + R2 + R3
R = 1 + 2 + 3
R = 6 Ω
Next, we shall determine the current flowing in the circuit.
This can be obtained as follow:
From ohm's law,
Voltage (V) = current (I) x resistance (R)
V = IR
Potential difference (V) = 12 V.
Resistance (R) = 6 Ω
Current (I) =?
V = IR
12 = I x 6
Divide both side by 6
I = 12/6
I = 2 A.
Since the circuit is in series connection, therefore, the same current will flow through each resistor.
Therefore, the current through the the 3 Ω load is 2 A.
what is the best defintion of efficency
Answer: Efficiency signifies a peak level of performance that uses the least amount of inputs to achieve the highest amount of output.
Explanation: It minimizes the waste of resources such as physical materials, energy, and time while accomplishing the desired output.
Answer:
The efficiency of a simple machine is defined as the ratio of useful work done by the machine ( output work) to the total work out into the machine ( input work).
Explanation:
EfficiencyIf a machine overcomes a load ' L ' and the distance travelled by the load is 'Ld' , the work done by the load is L× LD. It is also called output work or useful work.
Therefore, [tex] \boxed{Output \: work \: = L \: \times \: Ld}[/tex]
Likewise, The effort applied to overcome the load is 'E' and the distance covered by effort is 'Ed' , the work done by effort is E × Ed. It is also called input work.
Therefore, [tex] \boxed{Input \: work = E \times Ed}[/tex]
The efficiency of a simple machine is defined as the ratio of output work to the input work .
Therefore, [tex] \boxed{Efficiency ( η)= \frac{outpt \: work}{input \: work} \times 100\%}[/tex]
Efficiency is expressed in percentage. It is a ratio of two works. A machine is never 100% efficient. It is because no machine is friction free and due to friction, some of the input energy is wastes in the form of heat energy.
[tex] \mathrm{Hope \: I \: helped!}[/tex]
[tex] \mathrm{Best \: regards!}[/tex]
Which is
easier
Push
or pull.
when force is at angle
Answer:
pull
Explanation:
because when you push there is one component of force that adds to tge weight of body and hence there is more friction. Whwn you pull the vertical component of force is against the weight of body and hence friction is low.
the standard unit of measurement of preasure
2. What is
N/m square or Pascal
Answer:
Both are the same.
Explanation:
[tex]pressure= \frac{force}{area} = \frac{f}{a} = \frac{n}{m {}^{2} } [/tex]
The SI unit was named after Bláise Pascal to honor him.
Hope this helps ;) ❤❤❤
What is the approximate pressure of a storage cylinder of recovered R-404A that does not contain any non-condensable impurities and is stored in a room where the temperature is 80°F?A. 68 psigB. 72 psigC. 174psigD. 288 psig
Answer:
D. 288 psig
Explanation:
The storage cylinder of recovered R-404A is a mixture of R-125, R-143 and R-134. The refrigeration sector has low temperatures for installation. The pressure of cylinder at 80 F will be 288 psig. The pure refrigerants have inside a container have saturation temperature which is equal to ambient temperature.
