Answer:
The current value of the Hubble's constant = 73 km/sec/Mpc.
t = 71.9 trillion years will be the new age of universe if the Hubble constant = 700 km/s/Mpc
Explanation:
The current value of the Hubble's constant = 73 km/sec/Mpc. However, recent discoveries in the cosmology contradicts the idea of Hubble constant as being fixed. Some scientists are not agreeing on this value and the debate is going on.
Hubble law states that how fast universe is expanding or in other words, galaxies are expanding separating with a speed directly proportional to the distance of galaxies to the earth.
Hence,
v is directly proportional to d
where, v = apparent velocity
d = distance
if we equate velocity and distance then there comes Hubble constant.
v = [tex]H_{0}[/tex] x d
[tex]H_{0}[/tex] = 73 km/sec/Mpc
where, Mpc = Mega Parsec = 1 Mpc = 3.086 x [tex]10^{19}[/tex] km
We can use Hubble constant to tell the age of universe.
t = d/v
t = d/( [tex]H_{0}[/tex] xd)
t = 1/[tex]H_{0}[/tex]
Scientist calculated the age of universe by using Hubble constant, which is 13.4 billion years.
Now, if we hypothetically change the value of Hubble constant,
from [tex]H_{0}[/tex] = 73 km/sec/Mpc to [tex]H_{0}[/tex] = 700 km/sec/Mpc
then the age of universe will be:
t = 1/[tex]H_{0}[/tex]
first convert the units of new [tex]H_{0}[/tex] into 1/s
[tex]H_{0}[/tex] = (700) x (/3.08 x [tex]10^{19}[/tex] )
[tex]H_{0}[/tex] = 227.27 x[tex]10^{-19}[/tex] = 2.27 x [tex]10^{-21}[/tex] 1/s
So,
Age of universe will be:
t = 1/[tex]H_{0}[/tex] = 1/2.27x[tex]10^{-21}[/tex] 1/s
t = 2.27 x [tex]10^{21}[/tex] s
t = 71.9 trillion years
t = 71.9 trillion years will be the new age of universe if the Hubble constant = 700 km/s/Mpc
Given value:
Hubble Constant,
[tex]H_o = \frac{700 \ km/s}{Mpc}[/tex]We know,
[tex]Mpc = 3.086\times 10^{19} \ km[/tex]By substituting the value of "Mpc" in Hubble constant, we get
→ [tex]H_o = \frac{700}{3.086\times 10^{19}}[/tex]
[tex]= 227\times 10^{-19} \ 1/s[/tex]
[tex]= 2.27\times 10^{-21} \ 1/s[/tex]
The Hubble's time will be:
→ [tex]H_o = \frac{1}{t}[/tex]
or,
→ [tex]t = \frac{1}{H_o}[/tex]
[tex]= \frac{1}{2.27\times 10^{-21}}[/tex]
[tex]= 4.4\times 10^{20} \ seconds[/tex]
Thus the above approach is right.
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Need help y’all ASAP please...physics
Answer:
t = 3/8 seconds
Explanation:
h=-16t^2 - 10t+6
h= 0 when it hits the ground
0=-16t^2 - 10t+6
factor out a -2
0= -2(8t^2 +5t -3)
divide by -2
0 = (8t^2 +5t -3)
factor
0=(8t-3) (t+1)
using the zero product property
8t-3 = 0 t+1 =0
8t = 3 t= -1
t = 3/8 t= -1
t cannot be negative ( no negative time)
t = 3/8 seconds
please help thank you
which of the following statements BEST describes the difference between an atom and an ion ?
Answer:
well the correct answer is
d. An atom contains equal numbers of protons and electrons whereas an ion contains unequal numbers of protons and electrons .Explanation:
A charged atom is known as an ion, well it can be negative as well as positive charge.
if atom has more protons than electrons then it get positively charged and known as cationif the atom has more electrons that the number of protons then the atom get negatively charged and known as anionwhich is true about the way air flows
A. high pressure to low pressure
B. low pressure to high pressure
C. cold air to hot air
D. hot air to cold air
Answer:
A High-to-Low
Explanation:
its like water running down a hill.
a string attached to a 60.0 Hz vibr.ator creates a standing wave with 5 loops. What frequency would make 7 loops? (Unit = Hz)
Answer:
F=84.0 Hz
Explanation:
Using the equation f= n (v/2L), frequency equals number of loops times velocity over 2 times the length, in order to get 60.0 Hz of frequency from 5 loops, v/2L would have to equal 12. (12*5=60) v/2L is constant, so to find the frequency of 7 loops you would times 7 by 12 to get 84.0.
Hope this helped! :)
A 1.3-kg model airplane flies in a circular path on the end of a 23-m line. The plane makes
4.3 revolutions each minute.
a. What is the period of the motion?
b. What is the speed of the plane?
c. What is the acceleration of the model plane?
d. How much force must the line exert on the plane to keep it moving in the circular
motion?
(a) The plane makes 4.3 revolutions per minute, so it makes a single revolution in
(1 min) / (4.3 rev) ≈ 0.2326 min ≈ 13.95 s ≈ 14 s
(b) The plane completes 1 revolution in about 14 s, so that in this time it travels a distance equal to the circumference of the path:
(2π (23 m)) / (14 s) ≈ 10.3568 m/s ≈ 10 m/s
(c) The plane accelerates toward the center of the path with magnitude
a = (10 m/s)² / (23 m) ≈ 4.6636 m/s² ≈ 4.7 m/s²
(d) By Newton's second law, the tension in the line is
F = (1.3 kg) (4.7 m/s²) ≈ 6.0627 N ≈ 6.1 N
Determine the speed, wavelength, and frequency of light from a helium-neon laser as it travels through flourite. The wavelength of the light from the laser is 632.8 nm in air and the index of refraction of flourite is 1.434.
Answer and Explanation:
The computation is shown below:
As we know that
Frequency = Speed ÷ wavelength
= (3 × 10^8 )÷ (632.8 × 10^-9)
= 4.74 × 10^14 Hz
Speed in flourite is
= Vaccum speed ÷ refraction index
= 3 × 10^8 ÷ 1.434
= 2.092 × 10^8 m/s
wavelength is
= Speed in flourite ÷ frequency
= (3 × 10^8 × 632.8 × 10^-9) ÷ (1.434 × 3 × 10^8)
= 441.28nm
How far will a 10N force pull a car if the work done is 20J?
5) Choose the best revision of the following statement: "All the isotopes of a particular element decay radioactively by
emitting electrons."
A. All the isotopes of a particular element are stable and do not decay.
B. Some isotopes are stable and others are unstable. Unstable isotopes decay by emitting various subatomic
particles and radiation
C. Some isotopes are stable and others are unstable. Unstable isotopes decay by emitting protons or
electrons.
D. The statement is correct as it is currently written.
Answer:
B. some isotopes are stable and others are unstable. unstable isotopes decay by emitting various subatomic particles and radiation.
Explanation:
test gave me the answer so yeah :/ XD
Which of these is another name for Newton's
first law?
A. the law of action-reaction
B. the law of force and acceleration
C. the law of gravity
D. the law of inertia
use particle motion to explain what happens when molten steel becomes a steel beam to be used in construction.
Explanation:
A molten steel is in a liquid phase of matter. It has no defined volume of shape at this state. The particles inside this materials in this form is randomized by they are still attached to each other.
On cooling, when the molten steel solidifies and sets into a solid steel beam, the particles take up a fixed position and forms a definite shape and this confers a definite volume on them. The randomized particles stops and forms fixed crystals about their lattice. This way, the beam can carry and support a fixed amount of load.Determine the absolute pressure on the bottom of a swimming pool 30.0 mm by 8.4 mm whose uniform depth is 1.9 mm .
Answer:
=101343.62N/m^2
Explanation:
absolute pressure on the bottom of a swimming pool= atmospheric pressure +( 2 ×ρ ×g)
( 2 ×ρ ×g)= guage pressure
atmospheric pressure= 101325pa
h= height= 1.9 mm = 1.9×10^-3m
ρ = density of water
= 1000kg/m^3
g= acceleration due to gravity= 9.8m/s^2
Then substitute, we have
absolute pressure on the bottom of a swimming pool= 101325+ [0.0019 ×1000 × 9.8)]
=101343.62N/m^2
Hence, the absolute pressure on the bottom of a swimming pool is =101343.62N/m^2
in 1-2 complete sentences define "opportunity cost " in your own words
Answer:
Here you go, hope this helps! :)
Explanation:
Opportunity cost is the value of the next best thing you give up whenever you make a decision. It is "the loss of potential gain from other alternatives when one alternative is chosen". ... For example, opportunity cost is how much leisure time we give up to work.
What is the standard form for 2 × 10−3 ?
Answer:
17
Explanation:
2 x 10 = 20
20-3 = 17
Find the applied voltage of a telephone circuit that draws 0.017A through a resistance Of 5,000 ohms
A bullet has a mass of 0.06 kg. Starting from rest, after the gun's trigger is pulled, a constant force acts on the bullet for the next 0.025 seconds until the bullet leaves the barrel of the gun with a speed of 992 m/s.
What is the change in momentum of the bullet?
The change in momentum of the bullet : 59.52 kg m/s
Further explanationGiven
m=0.06 kg
Δt=0.025 s
vo=0(from rest)
vt= 992 m/s
Required
The change in momentum
Solution
The change in momentum = ΔP
ΔP =m(vt-vo)
ΔP =0.06(992-0)
ΔP =59.52 kg m/s
What happens to most of the light waves that strike a clear pane of glass? O A. absorption B. diffraction O C. reflection O D. transmission
slight reflect but most goes through because glass is transparent
Most of the light waves that strike a clear pane of glass reflects. Details about reflection can be found below.
What is reflection?Refection in physics is the property of a propagated wave being thrown back from a surface such as a mirror.
Mirror is an example of an object that could be hit by an incumbent wave, however, most of the light waves that hit the mirror surface gets reflected back.
Therefore, most of the light waves that strike a clear pane of glass reflects.
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fill in the blank:
the more people (greater mass) you load into a car, the ___ (more or less) it will accelerate with the same force applied by the engine.
the more people (greater mass) you load into a car, the more it will accelerate with the same force applied by the engine.
1. Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s,
Answer:
104653.13J
Explanation:
Given parameters:
Mass of roller coaster = 625kg
Speed = 18.3m/s
Unknown:
Kinetic energy = ?
Solution:
The kinetic energy is the energy due to the motion of a body.
Kinetic energy = [tex]\frac{1}{2}[/tex] x m x v²
m is the mass
v is the speed
Kinetic energy = [tex]\frac{1}{2}[/tex] x 625 x 18.3² = 104653.13J
Do you know how to do this clever ones hmmm?? Describe and explain the motion of a small ball floating on a pond when waves travel across the pond.
Answer:
Ball moves up and down repeatedly on surface because waves consist of successive crests and troughs moving across surface, each crest pushes ball up and each trough allows it to move down.
Explanation:
diffrence between:- movable pulley and fixed pully
Answer:
fixed pulley: A pulley system in which the pulley is attached to a fixed point and the rope is attached to the object. ... movable pulley: A pulley system in which the pulley is attached to the object; one end of the rope is attached to a fixed point and the other end of the rope is free.
Explanation:
A volleyball experiences 494 Ns of impulse over a time period of 7 seconds. What was the magnitude of the force that acted on the volleyball during this time period?
Answer:
70.6N
Explanation:
Given parameters:
Impulse = 494Ns
Time = 7s
Unknown:
Force applied = ?
Solution:
To solve this problem, we use the formula of impulse;
Impulse = Force x time
Now insert the parameters and solve;
494 = Force x 7
Force = [tex]\frac{494}{7}[/tex]
Force = 70.6N
Please answer the questions... I will surely mark you as the brainliest according to me :)
Answer:
(a) You can tell that have the same strength because they have attracted the same amount of paper clips.
(b) Iron is used in electromagnets because steel retained magnetic properties after the power was turned off, but in the iron, the paper clips dropped off right away.
4. A disobedient student dropped his Physics textbook (mass 0.1kg) from the window (15m above the ground). How fast was it going when it hit the ground?
Answer:
v= 17.15 m/s
Explanation:
mass of the book=0.1 Kg
height above ground, h= 15 m
Using conservation of energy
Potential energy is converted into kinetic energy
[tex]mgh = \frac{1}{2}mv^2[/tex]
[tex]v=\sqrt{2gh}[/tex]
[tex]v=\sqrt{2\times 9.8\times 15}[/tex]
[tex]v=\sqrt{294}[/tex]
v= 17.15 m/s
Hence, the book will hit the ground at the speed of 17.15 m/s.
Which region contains the alkaline earth metal family of elements? A, B, C or D?
Answer:
B
Explanation:
B is the most likely region that contains alkaline earth family elements.
The alkaline earth metal family of elements is represented by B region in the figure.
What is alkaline earth metal?The alkaline earth metals are found on the periodic table in Group 2, which is on the far left side of the table between Group 1, the alkali metals, and Groups 3-12, the transition elements. This family is made up of six metals: beryllium, magnesium, calcium, strontium, barium, and radium.
What is periodic table?The periodic table, also known as the periodic table of the elements, is a tabular display of the chemical elements.
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why does the force of air resistance affect the motion of a person traveling at high speed more than a person walking across the room?
Answer:
yes .
Explanation:
...
;-; :) have a good day
Answer:
because on air the speed is high compared to walking
how much KE does the car have if it weighs 450kg and moves at the speed of 23 m/s?
Answer:-The formula of to calculate KE = 1/2 m v^2
so we,
KE = 1/2 (450kg)(23m/s)^2
KE = 1/2 ×238050
KE = 119025
Explanation: In Physics Formulas mean everything.
A person lifts a heavy load to a vertical height of 2.0 m in 3 seconds. If he/she had done this more slowly in 6 seconds, the
work on the load would have been:
Four times as great
half as great
the same
twice as great
Answer:
If the heavy load had been lifted more slowly, the work done on the load would have been the same.
Explanation:
Work done on an object is given as;
W = Fd
where;
F is the force applied on the object
d is the displacement of the object
for the given question, the applied force on the load = mg (mass of the load multiplied by acceleration due to gravity).
Also, the displacement of the object = vertical height the load was lifted.
W = mgh
The work done on the load is independent of time.
Thus, if the heavy load had been lifted more slowly, the work done on the load would have been the same.
A person lifting a heavy load to a vertical height of 2.0 m in 3 seconds does the same work as if he/she lifts it in 6 s.
A person lifts a heavy load to a vertical height of 2.0 m in 3 seconds.
We want to compare the work done with the one that he/she would have done if the process had taken 6 seconds.
What is work?In physics, work (W) is the energy transferred to or from an object via the application of force (F) along a displacement (s).
W = F × s
Given the displacement is the same (2.0 m) and the force needed is also the same (weight of the object), the work is the same for both processes.
A person lifting a heavy load to a vertical height of 2.0 m in 3 seconds does the same work as if he/she lifts it in 6 s.
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A block of mass m is hung from the ceiling by the system of massless springs consisting of two layers. The upper layer consists of 3 strings in paralle, and the lower layer consists of 2 strings in parallel. The horizontal bar between the two layers has negligible mass. The force constants of all springs are k. Calculate the period of the vertical oscillations of the block.
Answer:
T₀ = 2π [tex]\sqrt{\frac{m}{k} }[/tex] T = [tex]\sqrt{\frac{5}{6} }[/tex] T₀
Explanation:
When the block is oscillating it forms a simple harmonic motion, which in the case of a spring and a mass has an angular velocity
w = [tex]\sqrt{k/m}[/tex]
To apply this formula to our case, let's look for the equivalent constant of the springs.
Let's start with the springs in parallels.
* the three springs in the upper part, when stretched, lengthen the same distance, therefore the total force is
F_total = F₁ + F₂ + F₃
the springs fulfill Hooke's law and indicate that the spring constant is the same for all three,
F_total = - k x - k x - kx = -3k x
therefore the equivalent constant for the combination of the springs at the top is
k₁ = 3 k
* the two springs at the bottom
following the same reasoning the force at the bottom is
F_total2 = - 2 k x
the equivalent constant at the bottom is
k₂ = 2 k
now let's work the two springs are equivalent that are in series
the top spring is stretched by an amount x₁ and the bottom spring is stretched x₂
x₂ = x -x₁
x₂ + x₁ = x
if we consider that the springs have no masses we can use Hooke's law
[tex]-\frac{F_{1} }{k_{1} } - \frac{F_{2}}{k_{2} } = \frac{F}{k_{eq} }[/tex]
therefore the equivalent constant is the series combination is
[tex]\frac{1}{k_{eq} } = \frac{1}{k_{1} } + \frac{1}{k_{2} }[/tex]
we substitute the values
\frac{1}{k_{eq} } = \frac{1}{3k } + \frac{1}{2k }
\frac{1}{k_{eq} } = \frac{5}{6k} }
k_eq = [tex]\frac{6k}{5}[/tex]
therefore the angular velocity is
w = [tex]\sqrt{\frac{6k}{5m} }[/tex]
angular velocity, frequency, and period are related
w = 2π f = 2π / T
T = 2π / w
T = 2π [tex]\sqrt{\frac{5m}{6k} }[/tex]
T₀ = 2π [tex]\sqrt{\frac{m}{k} }[/tex]
T = [tex]\sqrt{\frac{5}{6} }[/tex] T₀
a ball of diameter 10 cm and mass 10 grams is dropped in a container of water. the cross sectional area of the container is 100 cm2.. what is the change in the height of the water column
Answer:
h = 9.83 cm
Explanation:
Let's analyze this interesting exercise a bit, let's start by comparing the density of the ball with that of water
let's reduce the magnitudes to the SI system
r = 10 cm = 0.10 m
m = 10 g = 0.010 kg
A = 100 cm² = 0.01 m²
the definition of density is
ρ = m / V
the volume of a sphere
V = [tex]\frac{4}{3} \ \pi r^{3}[/tex]
V = [tex]\frac{4}{3}[/tex] π 0.1³
V = 4.189 10⁻³ m³
let's calculate the density of the ball
ρ = [tex]\frac{0.010}{4.189 \ 10^{-3} }[/tex]
ρ = 2.387 kg / m³
the tabulated density of water is
ρ_water = 997 kg / m³
we can see that the density of the body is less than the density of water. Consequently the body floats in the water, therefore the water level that rises corresponds to the submerged part of the body. Let's write the equilibrium equation
B - W = 0
B = W
where B is the thrust that is given by Archimedes' principle
ρ_liquid g V_submerged = m g
V_submerged = m / ρ_liquid
we calculate
V _submerged = 0.10 9.8 / 997
V_submerged = 9.83 10⁻⁴ m³
The volume increassed of the water container
V = A h
h = V / A
let's calculate
h = 9.83 10⁻⁴ / 0.01
h = 0.0983 m
this is equal to h = 9.83 cm
If the angle between the net force and the displacement of an
object is greater than 90 degrees, then which option holds
true?
aThe object stops
b Kinetic energy decreases
C Kinetic energy increases
d Kinetic energy remains the same
Answer: kinetic energy decreases
Explanation:
When the angle between the net force and the displacement of an
object is greater than 90 degree, the Kinetic energy decreases.
The work done by a net force in moving an object over a given distance is given as;
[tex]W = F \times d \ cos(\theta)[/tex]
where;
θ is the angle between the net force and the displacementThe value of cos(θ) decreases from 0 to 180, consequently, the value of work-done will decrease as well.
Based on work-energy theorem, the work done on the object is equal to kinetic energy of the object.
[tex]W = K.E[/tex]
Thus, we can conclude that when the angle increases, the Kinetic energy decreases.
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