Answer:
First, as you may know, the light travels at a given velocity.
In vaccum, this velocity is c = 3x10^8 m/s.
And we know that:
distance = velocity*time
Now, if some object (like a star ) is really far away, the light that comes from that star may take years to reach the Earth.
This means that the images that the astronomers see today, actually happened years and years ago (So the night sky is like a picture of the "past" of the universe)
Also, for example, if an astronomer sees some particular thing, he can apply a model (a "simplification" of some phenomena that is used to simplify it an explain it) and with the model, the scientist can infer the information of the given thing some time before it was seen.
The astronomers could know what was happening inside galaxies way back then by the fact that;
they examine the spectra of galaxies (or the overall colors of galaxies) with the highest redshifts they can find
Astronomers Measure the wavelength of the light that is stretched, so the light is seen as 'shifted' towards the red part of the spectrum by using spectroscopy. This measure is also called redshift.
This invokes a ray of light through a triangular prism that splits the light into various components known as spectrum.
The way the astronomers could use this concept to know what was happening in the galaxies before is by examining the spectra of galaxies that have the highest redshifts.
Read more at; https://brainly.com/question/15995216
Suppose an experiment is designed to test the durability of batteries in different conditions. All of the batteries tested are double-A (AA) Brand X. All sets of batteries are preconditioned in different environmental conditions for exactly 168 hours (1 week).
Set 1: 0°C (freezing point of water)
Set 2: 24°C (approximately room temperature)
Set 3: 37°C (approximately body temperature)
The batteries are then continuously used to power identical mechanical drummer toys. As long as the toy keeps drumming the battery is considered functional. The drumming time for each toy is measured as an indication of battery durability. In this experiment, which condition is not controlled?
A.) temperature
B.) brand of batteries
C.) test for durability
D.) type of battery (battery size)
Answer:
I assume its c. Since its talking about testing.
Explanation:
Answer:
The answer is test of durability
Explanation:
observe the virual skateboarder coming down the hill and over the ramp describe how each of newton’s laws of motion can be observed in this action you can choose the dry wet or muddy conditions or some combination of these
Answer:
first part the skater goes down a constant slope ramp, initially he has Newton's second law
pply Newton's third law, the normal is the reaction to the support of the body on the surface
the ramp shoots off. axis becomes zero and therefore with Newton's first law its speed
Explanation:
It is the description of this movement let's write Newton's laws.
* The first law that a body goes at constant speed or zero if the sum of the external forces is zero
* the second law is F = m a
* The third law states that the forces act in pairs of equal magnitude and opposite direction, one applied to each body.
Let's apply these laws to our case
In the first part the skater goes down a constant slope ramp, initially he has Newton's second law when he accelerates from the initial velocity of zero to a terminal velocity.
The expression for this is
Wₓ - fr = ma
W sin θ - μ W cos θ = m a
W = mg
g (sin θ - μ cos) = a
the value of the coefficient of kinetic friction depends on the condition of the surface, dry, wet or muddy
This is Newton's second law
On the Y axis, which is perpendicular to the ramp we have
N- [tex]W_{y}[/tex] = 0
If we apply Newton's third law, the normal is the reaction to the support of the body on the surface, note that it can be different from the weight.
In the second part when he is on the ramp.
In the ramp the skater enters with a speed v, suppose that the ramp has an incline so that the skater can jump, in this case the angle is positive with respect to the axis x
In this case the analysis is similar to the previous one
Newton's second law gives the acceleration of the skater, who when he reaches the end of the ramp shoots off.
At this point the force in the x (horizontal) axis becomes zero and therefore with Newton's first law its speed this axis remains constant and the force in the y axis is the force of gravity and has an acceleration that changes if velocity according to Newton's second law
Answer:look at explanations
Explanation:
Will mark as BRAINLIEST.......
The position vector is given by vector r= 5t² I cap + 2 t³ j cap + 2 k cap. Find it's velocity and acceleration at t=2s.
Answer:
We have the position vector given in terms of time t. r(t) = t^3*i + t^2*j
To find the velocity vector we have to differentiate r(t) with respect to time.
r'(t) = 3t^2*i + 2t*j
The vector representing acceleration is the derivative of the position vector
r''(t) = 6t*i + 2*j
When time t = 2.
The velocity vector is 3*2^2*i + 2*2*j
=> 12*i + 4*j
The speed is the absolute value of the velocity vector or sqrt(12^2 + 4^2) = sqrt (144 + 16) = sqrt 160
The acceleration vector is 6*2*i + 2*j
=> 12*i + 2*j
The required acceleration at t=2 is 12*i + 2*j and the speed is sqrt 160.
Explanation:
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an object weights 0.250 kgf in air 0.150 in water and 0.125 in an oil.find out the density of the object and the oil
Answer:
1) The density of the object = 2500 kg/m³
2) The density of the oil = 1250 kg/m³
Explanation:
1) The information relating to the question are;
The mass of the object in air = 0.250 kgf
The mass of the object in water = 0.150 kgf
The mass of the object in the oil = 0.125 kgf
By Archimedes's principle, we have;
The upthrust on the object in water = Mass in air - mass in water = The weight of the water displaced
The upthrust on the object in water = 0.250 - 0.150 = 0.1 kgf
∴ The weight of the water displaced = 0.1 kgf
Given that the object is completely immersed in the water, we have;
The volume of the water displaced = The volume of the object
The volume of 0.1 kg of water water displaced = Mass of the water/(Density of water)
The volume of 0.1 kg of water = 0.1/1000 = 0.0001 m³
The density of the object = (Mass in air)/ volume = 0.250/0.0001 = 2500 kg/m³
The density of the object = 2500 kg/m³
2) Whereby the mass of the object in the oil = 0.125 kgf
The upthrust of the oil = The weight of the oil displaced
The upthrust of the oil on the object = Mass of the object in air - mass of the object in the oil
The upthrust of the oil on the object = 0.250 - 0.125 = 0.125 kgf
The weight of the oil displaced = The upthrust of the oil
Given that the volume of the oil displaced = The volume of the oil, we have;
The volume of the oil displaced = 0.0001 m³
The mass of the 0.0001 m³ = 0.125 kg
Therefore the density of the oil = 0.125/0.0001 = 1250 kg/m³.
The density of the oil = 1250 kg/m³.
in the derivation of the time period of a pendulum in electric field when considering the fbd of bob to find the g effective why do we neglect tension
Answer:
we learned that an object that is vibrating is acted upon by a restoring force. The restoring force causes the vibrating object to slow down as it moves away from the equilibrium position and to speed up as it approaches the equilibrium position. It is this restoring force that is responsible for the vibration. So what forces act upon a pendulum bob? And what is the restoring force for a pendulum? There are two dominant forces acting upon a pendulum bob at all times during the course of its motion. There is the force of gravity that acts downward upon the bob. It results from the Earth's mass attracting the mass of the bob. And there is a tension force acting upward and towards the pivot point of the pendulum. The tension force results from the string pulling upon the bob of the pendulum. In our discussion, we will ignore the influence of air resistance - a third force that always opposes the motion of the bob as it swings to and fro. The air resistance force is relatively weak compared to the two dominant forces.
The gravity force is highly predictable; it is always in the same direction (down) and always of the same magnitude - mass*9.8 N/kg. The tension force is considerably less predictable. Both its direction and its magnitude change as the bob swings to and fro. The direction of the tension force is always towards the pivot point. So as the bob swings to the left of its equilibrium position, the tension force is at an angle - directed upwards and to the right. And as the bob swings to the right of its equilibrium position, the tension is directed upwards and to the left. The diagram below depicts the direction of these two forces at five different positions over the course of the pendulum's path.
that's what I know so far
you walk 6 block east, 2 blocks north, 3 blocks west and then 2 blocks north. the total distance you travel is blocks
Answer:
The answerI travel 13 blocksIdentify the wood turning equipment and what it does.
А
is used to turn wood. It rotates and carves wood to produce a
form.
Answer:
lathe
perfectly symmetrical
Answer: A lathe is used to turn wood . It rotates and carves wood to produce a perfectly symmetrical form .
First one is lathe .
Second one is perfectly symmetrical .
Explanation: I just took the test on Plato and had 100%
Find the odd one out a)Planets moving on it's axis,Strings of guitar (being played),Motion of a ferry wheel,The vehicles moving on a straight road. b)Motion of the moon around the earth,Motion of the earth around the sun,Motion of a merry-go-round,Heart-beat in a healthy person. c)Motion of a bullet fired from gun,Motion of a football player in the ground,Motion of a vehicle on a straight road,Motion of an apple falling from a tree
Answer:
a) Strings of guitar (being played)
b) Heart-beat in a healthy person
c) Motion of an apple falling from a tree
Explanation:
a) The motion of the string of a guitar being played is the only motion involving simple harmonic motion.
b) All the other motions are circular motion except the heart beat in a healthy person, which is periodic.
c) The motion of an apply falling from a tree is the only motion under the complete influence of gravity from the onset till the end.
Question 5
Calculate the kinetic energy of a car (m - 800 kg) moving at 15 m/s. Write your answer to the nearest whole number in the blank space
provided. Only write the numerical value of the answer without units. Do not leave any space in between numbers.
Answer: Joules
Answer:
90,000Explanation:
[tex]m =800kg\\v = 15\\\\K.E = \frac{1}{2}mv^2\\ K.E= \frac{1}{2} \times 800\times 15^2\\= 400 \times 225\\= 90000 joules\\= 90 kilojoules[/tex]
The pH scale is used to tell if a substance
is an acid or base. Substances with a pH
of 7 are neutral. An acid is anything
below 7 and a base is anything above 7.
Bleach has a pH of about 12. What type of
substance is bleach?
A. base
B. acid
C. neutral
Answer: Bleach is a base
Explanation: If bleach had a pH level of 12, a number above 7, than it is a base. Hope this helps!
element X has two isotopes: X-27 and x-29. x-27 has an atomic mass of 26.975 and a relative abundance of 82.33%, and X-29 has an atomic mass of 29.018 and a relative abundance of 17.67%. calculate the atomic mass of element X. show your work
Answer:
27.34 (no unit)
Explanation:
26.975*82.33%+29.018*17.67%
=27.34
State 1 difference between 1 way rotary motion and reversible rotary motion
Answer:
The difference between One-way as well as reversible rotary motion is described below.
Explanation:
Unless rotary motions occur restricted to single direction exclusively (i.e. whether clockwise as well as anti-clockwise only), it is defined as another rotary 'one-way' motion.This motor establishes that continuously variable movement at 360 ° chemically guided is conceivable. The rotating is regulated, and for a particular direction, the biochemical occurrences guiding rotation become incredibly selective.An archer shoots an arrow in the air, horizontally. However, after moving some
distance, the arrow falls to the ground. Name and define the initial force that sets
the arrow in motion. Explain why the arrow ultimately falls down.
Answer:
The name of the force is elastic (spring) force
Explanation:
The elastic force which is the restoration force of an elastic (spring like) object that tries to return to its initial non-stretched state built up by the pulling of the bow by the archer (using the muscles) pushes on the arrow which the archer releases the same time he leaves the bow string, and the arrow flies in the direction already pointed by the archer
The arrow ultimately falls down due to gravity forces that acts on all objects within the Earths gravitational field. However due to the speed of constant horizontal speed of the arrow and increasing downward speed of the due to the gravity force, the falling of the arrow looks disappointing.
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
You and your family are going on a trip in Europe. Calculate the speed in the following scenario. State how you calculated your answer and include correct units. A car travels 240 kilometers in 3 hours; What is the speed of the car during that time?
Answer:
22.2 m/s or 80 km/h
Explanation:
Given that
Distance travelled by the car, d = 240 km
Time taken by the car, t = 3 hours.
Speed of the car, v = ? m/s
for easy calculations, we will be converting the units to meters and seconds respectively.
240 km to meters would be
240 * 1000 m = 240000 m
3 hrs to seconds would be
3 * 60 mins * 60 seconds = 10800 s
now, we have our distance and time to be
d = 240000 m
t = 10800 s
speed is defined as the ratio of distance with respect to time taken, effectively,
Speed = distance/time
speed, v= 240000 / 10800
v = 22.2 m/s
therefore, the speed of the car during the time is 22.2 m/s, or if the speed is needed in km/h, we can convert it
22.2 * 3600/1000 =
80 km/h
Can someone please illustrate how the refracted ray will look like?
Answer
As the angle of incidence increases in Figure 2.8, a point is finally reached where the refracted ray does not emerge at the second layer but lie along the interface. This particular angle of incidence at which the angle of refraction is 90° and the refracted ray lies along the interface is known as the critical angle. At and beyond the critical angle, there is no transmitted ray and therefore a very high reflected ray will be recorded .
Therefore,
sinθisin90=Vp1Vp2
But, sin 90 = 1.
At critical angle,
sinθcritical=Vp1Vp2
A critical refracted wave travels along the interface between layers and is refracted back into the upper layer at the critical angle. The waves refracted back into the upper layer are called head waves or first-break refractions because at certain distances from a source, they are the first arriving energy. Recorded first-break refraction is shown in Figure 2.10.
Note that these first-break refractions can give us important information about the shallow velocities on land seismic data.
Note also that seismic data are acquired in such a way that reflections from horizons of interest are in the pre-critical region, even at the farthest offset in the data.
In reality, part of the seismic energy arriving at an interface is transmitted and refracted, and another part of the energy is reflected at that same interface. Given that there are many reflectors in the subsurface, there will be many paths from source to receiver, each of them with a different travel time. The proportion of energy reflected depends on the material properties of the two bounding layers and on the angle of incidence
give an example of a balanced force and explain what makes it a balanced force
If 60 L of a gas are at 4 atm and 27 C °, what pressure would it have if the volume is 40 L 127 C °?
Answer:
8 atm
Explanation:
Ideal gas law:
PV = nRT
where P is pressure, V is volume, n is moles, R is universal gas constant, and T is absolute temperature.
If n is constant:
PV / T = PV / T
(4 atm) (60 L) / (27 + 273) K = P (40 L) / (127 + 273) K
0.8 atm = 0.1 P
P = 8 atm
A person holds a 25 kg (250 newton) bag of cement over his head and moves it a distance of 10 m, taking 2 minutes, while another person carries it on a wheelbarrow that same distance, taking 1 minute.Who does more work ? What is the power of each person?
Explanation:
Assuming the 10 m distance is the vertical displacement, the work done by both people is the same.
Work = force × distance
W = (250 N) (10 m)
W = 2500 J
The power of the first person is:
Power = work / time
P = 2500 J / 120 s
P = 20.83 W
The power of the second person is:
P = 2500 J / 60 s
P = 41.67 W
I need help pls now plleeeeeeeeaaassseeeee
Answer:
[tex]r = \frac{v}{i} = v = ri \\ i = \frac{v}{r} [/tex]
A narrow beam of light containing red (660 nm) and blue (470 nm) wavelengths travels from air through a 1.00 cm thick flat piece of crown glass and back to air again. The beam strikes at an incident angle of 30 degrees. (a) At what angles do the two colors emerge
Answer:
The color blue emerges at 19.16° and the color red emerges at 19.32°.
Explanation:
The angle at which the two colors emerge can be calculated using the Snell's Law:
[tex]n_{1}sin(\theta_{1}) = n_{2}sin(\theta_{2})[/tex]
Where:
n₁ is the refractive index of the incident medium (air) = 1.0003
n₂ is the refractive index of the refractive medium:
blue light in crown glass = 1.524
red light in crown glass = 1.512
θ₁ is the angle of the incident light = 30°
θ₂ is the angle of the refracted light
For the red wavelengths we have:
[tex] \theta_{2} = arcsin(\frac{n_{1}sin(\theta_{1})}{n_{2}}) = arcsin(\frac{1.0003*sin(30)}{1.512}) = 19.32 ^{\circ} [/tex]
For the blue wavelengths we have:
[tex] \theta_{2} = arcsin(\frac{n_{1}sin(\theta_{1})}{n_{2}}) = arcsin(\frac{1.0003*sin(30)}{1.524}) = 19.16 ^{\circ} [/tex]
Therefore, the color blue emerges at 19.16° and the color red emerges at 19.32°.
I hope it helps you!
Shortly after receiving a traffic ticket for speeding, Fred made numerous comments about the road signs being inadequate and is GPS telling him a different speed limit. This would be an example of:
Answer:
External locus of control
Explanation:
External locus of control is an attitude people possess that makes them attribute their failures or successes to factors other than themselves. The opposite of this type of attitude is the Internal locus of control where the individuals take responsibility for the outcomes of their actions whether good or bad. One good thing about the external locus of control is that when the individuals with this characteristic record successes, they attribute it to others and this presents them as people with team spirit. However, when they record failures, they do not want to take the blame, but rather attribute it to others.
Fred exhibits an external locus of control because he attributed his speeding to other factors like the road signs and GPS instead of fully admitting that it was his fault.
On a frictionless air track, a 0.30 kg glider moving at 0.40m/s to the right collides with a stationary 0.80kg glider moving at 0.15 m/s to the left. The collision is cushioned by a bumper made of perfectly elastic spring steel. a. What is the velocity of each glider after the collision? b. What is the minimum amount of total kinetic energy during the collision? c. Where is the missing energy?
Answer:
Explanation:
It is the case of perfectly elastic collision . So we shall apply formula of velocity after collision as follows .
Let m₁ and m₂ be the mass colliding with velocity u₁ and u₂ and their velocity become v₁ and v₂ after collision .
[tex]v_1=\frac{(m_1-m_2)u_1 }{m_1+m_2)} +\frac{2 m_2u_2}{(m_1+m_2)}[/tex]
Putting the values
[tex]v_1=\frac{ (.30-.80).40 }{( .30+.80)} +\frac{2\times .80\times(-.15) }{(.30+.80 )}[/tex]
= - 0.4 m /s
So direction of .30 kg mass will be reversed .
[tex]v_2=\frac{ ( m_2-m_1) u_2 }{( m_1+m_2)} +\frac{2 m_1u_1}{(m_1+m_2)}[/tex]
putting the values
[tex]v_2=\frac{ ( .80-.30)(-.15) }{( .30+.80)} +\frac{2 \times.30\times.40}{(.30+.80)}[/tex]
= .15 m /s
The direction of .80 kg will become from left to right ie its direction will be reversed .
b ) Minimum amount of kinetic energy will be at the position when they move with common velocity
common velocity
v = .3 x .4 - .8 x .15 / (.3 + .8)
= 0
c )
Missing energy is stored as elastic potential energy in the spring .
lab safety test Safety goggles and an apron must be worn when handling chemicals labeled corrosive because they:________.
Answer: React with the skin
Explanation:
lab safety test Safety goggles and an apron must be worn when handling chemicals labeled corrosive because they React with the skin
Self-Check
por Learning
A truck mass 8000 kg and a car a mass 1000
kg are travelling at the same velocity. Which one has greater kinetic energy ? Why?
Answer:
K.E of truck > K.E of car
Explanation:
Mass of the truck = 8000Kg
K.E=[tex]\frac{1}{2} mv[/tex]
K.E =[tex]\frac{1}{2}*8000*v\\ 4000v[/tex]
Mass of the car = 1000 Kg
K.E of the car =[tex]\frac{1}{2}*1000*v\\ 500v[/tex]
Therefore Kinetic energy of the truck is greater than that of the car
select the correct relationship of the densities of the given substances: !●water < iron < aluminium < mercury ● Iron < water < mercury < aluminium ● water < aluminium < iron < mercury ● none of the above. asap plz!!!
Answer:
option a is correct
Explanation:
water ∠iron∠aluminium∠mercury
water density =1.0000
iron =7.487
aluminium=2.07
mercury=13.59
A construction worker uses an electrical device to attract fallen nails and sharp objects
from a construction site. What is causing the attraction of the metal objects?
O An electrical wave oscillating perpendicular to the electrical device.
O An electrical charge radiating perpendicular to the wire
O Amagnetic wave radiating perpendicular to an electrical device
O A magnetic wave and electrical current moving in opposite directions
Answer:
is the last one, a magnetic wave and electrical current moving in opposite directions
Explanation:
opposite directions always attract in magnetic waves and fields
Describe the motion of water waves.
Answer:
Water waves are an example of waves that involve a combination of both longitudinal and transverse motions. As a wave travels through the waver, the particles travel in clockwise circles. The radius of the circles decreases as the depth into the water increases.
Which waves move fast Longitudinal waves or Transverse waves and why???
Answer:
Transverse wave
Explanation:
Its because in transverse wave the particle displacement is perpendicular to the direction of wave propagation..hope it helps you...
A 2-kg cart, traveling on a horizontal air track with a speed of 3m/s, collides with a stationary 4-kg cart. The carts stick together. The impulse exerted by one cart on the other has a magnitude of
Answer:
The impulse exerted by one cart on the other has a magnitude of 4 N.s.
Explanation:
Given;
mass of the first cart, m₁ = 2 kg
initial speed of the first car, u₁ = 3 m/s
mass of the second cart, m₂ = 4 kg
initial speed of the second cart, u₂ = 0
Let the final speed of both carts = v, since they stick together after collision.
Apply the principle of conservation of momentum to determine v
m₁u₁ + m₂u₂ = v(m₁ + m₂)
2 x 3 + 0 = v(2 + 4)
6 = 6v
v = 1 m/s
Impulse is given by;
I = ft = mΔv = m(
The impulse exerted by the first cart on the second cart is given;
I = 2 (3 -1 )
I = 4 N.s
The impulse exerted by the second cart on the first cart is given;
I = 4(0-1)
I = - 4 N.s (equal in magnitude but opposite in direction to the impulse exerted by the first).
Therefore, the impulse exerted by one cart on the other has a magnitude of 4 N.s.
