what are the milestones of modern phyiscs?
Answer:
The articles appearing under "Milestones in Physics" will give an insight into special events or situations that have been decisive for the evolution of Physics
Answer:
We have invented many new ways to get energy, especially renewable means of energy, and we have made many new carbon-neutral devices more widespread and cheaper.
Modern physics milestones are getting harder and harder to get because almost every element has been discovered, many gaseous and liquid substances have been experimented with and dozens of other mid 20th century discoveries.
What is the relationship between latent heat and the hydrogen bonds which hold the molecules together?
Answer:
The molecules form strong hydrogen bonds, and water has a correspondingly high latent heat of vaporization. When no strong bonds are present, heating a liquid can easily free the molecules to form a gas, and the latent heat of vaporization is low.
Explanation:
Calculate the average velocity of the cart for each fan speed. Round your answers to the nearest tenth. The cart with Low fan speed has an average velocity of cm/s. The cart with Medium fan speed has an average velocity of cm/s. The cart with High fan speed has an average velocity of cm/s.
A 4-column table with 3 rows. Column 1 has entries Elapsed time to finish line(s); Total distance (c m); Average velocity (c m/s). Column 2 is labeled Cart Speed (Low Fan Speed) (c m/s) with entries 7.4; 500; unknown. Column 3 is labeled Cart Speed (medium Fan Speed) (c m/s) with entries 6.4; 500; unknown. Column 4 is labeled Cart Speed (High Fan Speed) (c m/s) with entries 5.6; 500; unknown.
This is defined as the rate of change of position of an object with respect to time. The unit is metres per second(m/s).
Velocity = distance/ time
The velocity for column 1 = 500m/7.4s = 67.57m/s.
The velocity for column 2 = 500m/6.4s = 78.13m/s.
The velocity for column 3 = 500m/5.6s = 89.29m/s.
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Answer:
67.6
78.1
89.3
Explanation:
2. What value did you calculate for the index of refraction of the acrylic block in Part 2? How does your value compare to the accepted value of 1.50? Calculate the percentage error. Different materials have distinct indexes of refraction. Explain how you might identify a material based on experiments like this one. Mention at least one of the difficulties in identifying materials based on their indexes of refraction.
The percentage error in calculated value of the refractive index of acrylic block is calculated using the formula: (true value - calculated value/true value) × 100%.
What is refractive index of a refracting medium?The refractive index of a medium is the ratio of the sine of the angle of incidence on the medium and the sine of the angle of refraction.
Refractive index = sin i/sin rwhere;
i is the angle of incidencer is angle of refraction.The refractive index of a medium increases with density of the medium.
To determine the percentage error in determining the refractive index of a medium, the following formula is used:
Percent error = error/true value × 100%Therefore, the percentage error in calculated value of the refractive index of acrylic block is the ratio of the error and true value multiplied by 100%.
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The higher the wattage of a light bulb, the more work the light bulb does. Group of answer choices
True
False
Answer:
True.
Explanation:
The higher the wattage the brighter the light. The efficiency of the system was introduced using and coletician lamps
An athlete lifts a 330 N set of weights from ground level to a position over her head, a vertical distance of 2.05 m. Assume the weights are moved at constant speed. a) How much work does the athlete do? b) What is the mass of the weights?
Work done:-
Force×Displacement330(2.05)676.5JNow
Apply Newtons second law
F=mam is mass
a is acceleration due to gravity (10)
330=10mm=33kgA proton's speed as it passes point A is 4.00×104 m/s . It follows the trajectory shown in the figure. What is the proton's speed at point B?
We know that:
[tex]0.5m(vB^{2} -vA^{2} )=q*[VB-VA]\\== > vB^{2} =vA^{2} +(\frac{2q}{m})*[VB-VA]\\ =(4.30*10^{4} )^{2} +(\frac{2*1.6*10^{-19} }{2*1.67*10^{-27} }) [-10-30]\\[/tex]
[tex]=18.49*10^{8} -76.64*10^{8}[/tex]
[tex]=-58.15*10^{8} \\== > vB=-7.62*10^{4} m/s[/tex]
The proton's speed at point B is -7.62 x ×10⁴ m/s.
What is proton?The proton is a subatomic particle lies inside the nucleus of an atom of element. The number of proton gives an idea of the atomic number of the element.
The proton's speed as it passes point A is 4.00×10⁴ m/s . It follows the trajectory shown.
1/2m (vb² - va²) = q (Vb - Va)
vb² = va² +2q/m (Vb - Va)
where v is the velocity and V is the potential at point A and B, q ia the charge on proton and m is the mass of proton.
Substitute the given values, we get
vb² = (4.00×10⁴ ) + (2x1.6 x 10⁻¹⁹/1.67 x 10⁻²⁷) (-10 - 30)
vb = -7.62 x ×10⁴ m/s
Thus, proton's speed at point B is -7.62 x ×10⁴ m/s.
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CAN SOMEONE PLS HELP ME!!!
Answer:
c
Explanation:
the question answered itself.
Does every light source emit only one type of light?
Yes it is possible. Spectrum of emitted light depends upon the chemical composition of the source. and the way of its excitation. a clear example to us is that of sun.
A race car goes forward from 0 to a velocity of 80 m/s in 9.4 s. What is its acceleration?
Answer:
The average acceleration is about 8.51 m/s
Explanation:
We can use the formula for acceleration to solve.
a = [tex]\frac{velocity_{final} -velocity_{start} }{time}[/tex]
a = [tex]\frac{80-0}{9.4}[/tex]
a = [tex]\frac{80}{9.4}[/tex]
a ≈ 8.51
A __________is a large cool star located in the top right of the HR diagram.
Answer:
Vermeer star is located at the top of large Venus
You are an astronaut floating in DEEP space (very little gravity). If you come upon a small metal object,
what can you do to test if the object has MORE or LESS mass than you? What would happen? Explain
A capacitor of cylindrical shape as shown in the red outline, few cm long carries a uniformly distributed charge of 7.2 uC per meter of length. By constructing a suitable Gaussian surface around the wire, Find the magnitude and direction of the electric field at points (a) 5.5 m and (b) 2.5 m perpendicular from the center of the wire. Show your detailed calculations and comment on the results.
Hi there!
Begin by using Gauss' Law to find the electric field.
[tex]\oint {E \cdot} \, dA = \frac{Q_{encl}}{\epsilon_0}[/tex]
E = Electric field (N/C)
dA = differential area element
Q = enclosed charge (C)
ε₀ = Permittivity of free space (8.85 * 10⁻¹² C²/Nm²)
We can construct a large cylinder around the wire in order to determine the electric flux. The electric field lines will pass through the LATERAL surface area of the cylinder, so:
[tex]A = 2\pi rL[/tex]
Where 'L' is the length of the cylinder and 'r' is the distance from the capacitor.
The enclosed charge is equivalent to the charge per meter length (λ) multiplied by the length, so:
[tex]\oint {E \cdot} \, dA = \frac{\lambda L}{\epsilon_0}[/tex]
We can rewrite the dot product as EA (where cosθ = 1 since the normal vector points in the direction of the field).
A = the lateral surface area of a cylinder, so:
[tex]E * 2\pi rL = \frac{\lambda L}{\epsilon_0}[/tex]
Rearrange to solve for 'E'.
[tex]E = \frac{\lambda L }{2\pi r L \epsilon _0}\\\\E = \frac{\lambda }{2\pi r \epsilon_0}[/tex]
a)
Plug in the distance into 'r'.
[tex]E = \frac{\lambda }{2\pi r \epsilon_0} \\\\E = \frac{0.0000072}{2\pi * 5.5 * (8.85 * 10^{-12})} = \boxed{23542.18 \frac{N}{C}}[/tex]
b)
Repeat:
[tex]E = \frac{\lambda }{2\pi r \epsilon_0}\\\\E = \frac{0.0000072}{2\pi * 2.5 * (8.85 * 10^{-12})} = \boxed{51792.8 \frac{N}{C}}[/tex]
We can see that the distance from the wire is INVERSELY related to the electric field strength by a power of r⁻¹. The field strength DECREASES as the distance INCREASES.
A negatively charged plastic comb is brought close to, but does not touch, a small piece of paper. If the comb and the paper are attracted to each other the charge on the paper
A) must be negative
B) may be positive or neutral
C) may be negative or neutral D)must be positive
If the comb and the paper are attracted to each other the charge on the paper, is D)must be positive
Laws of electrical attraction
This states that
Like charges attract Unlike charges repelNow, given that a negatively charged plastic comb is brought close to, but does not touch, a small piece of paper. If the comb and the paper are attracted to each other the charge on the paper, this implies that both the negatively charged plastic comb and the paper have opposite charges.
Since the charge on the plastic comb is negative, this means that the charge on the paper must be positive
So, if the comb and the paper are attracted to each other the charge on the paper, is D)must be positive
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Suppose that a car speaker produces sound waves with a frequency of 4000 Hz. As the car speaker moves away from an observer, which of the
following occurs?
Frequency is reduced with the sound waves being less heard when the speaker moves away from an observer.
What is Frequency?
This is defined as the number of occurrences of a repeating event per unit of time.
As the speaker is moved away from the observer, the wavelength increases and the frequency decreases thereby resulting in less sound being heard.
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What is the absolute error expression of this ?
Answer:
n=(A+B)+k4
Explanation:
because if u add all the things to it u will get that
2. Which of the diagrams shows the least gravitational force between the two objects?
a. I
b. II
c. III
d. IV
Which of the diagrams shows the least gravitational force between the two objects?
Options :-a. I
b. II
c. III
d. IV
Answer :- Option D . IV Explanation :- Gravitational force directly proportional to both the masses and in 4th and 3th case we have least mass of 2 on both side which is less than 10 in 2 cases Gravitational force is inversely proportional to square of the distance between the masses and in case 1st and 4th we have more distance than in 2nd and 3th . we know larger the distance lesser will be the forceFrom above observation we can conclude that gravitational force is least in 4th case because we have less mass on both side and we have more distance between the 2 masses that others with same mass .
A light bulb operating at a dc voltage of 120 V has a power rating of 60 W. How much current is flowing through this bulb
[tex]\\ \rm\rightarrowtail I=\dfrac{P}{V}=\dfrac{60}{120}=\dfrac{1}{2}=0.5A[/tex]
1. Greek scientist called Archimedes was asked to check the purity of the gold in a crown. He did this by comparing the density of the crown with the density of pure gold.
a) Describe how he could have measured the density of an irregular shaped object as a crown.
Answer:
Suppose Archimedes weighed the crown (we'll say 2700 grams)
Then he put the crown on a string and weighed the crown in water and found its weight to be 2560 g.
That means that an equivalent volume of water weighed
2700 - 2560 = 140 grams
Then the density of the crown is 2700 / 140 = 19.3
So this is the density of pure gold and the crown could be considered to be made of pure gold with no other metals in its composition.
Archimedes weighed the crown, then suspended it on a rope and measured the volume of water it displaced in order to determine its weight, then he calculated the density of the crown and compared it with the density of the pure gold.
What is density?It can be defined as the mass of any object or body per unit volume of the particular object or body. Generally, it is expressed as in gram per cm³ or kilogram per meter³.
As given in the problem statement Greek scientist called Archimedes was asked to check the purity of the gold in a crown. He did this by comparing the density of the crown with the density of pure gold.
Archimedes weighed the crown, then suspended it on a rope and measured the volume of water it displaced in order to determine its weight.
Thus, he could have measured the density of an irregularly shaped object as a crown.
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The SI unit for force is the _________.
A. mass
B. kilogram
C. newton
D. acceleration of gravity
E. weight
Answer:
Newton
Explanation:
The SI unit for force is the newton.
Answer:
The SI unit of kilogram is Newton. It is denoted by n
What is an analogy of two different roads or rivers to compare a series and parallel circuit?
Answer:
In a series circuit, the same amount of current flows through all the components placed in it. On the other hand, in parallel circuits, the components are placed in parallel with each other due to which the circuit splits the current flow.
define briefly what is second conditionofequilibrium with examples
I’m sorry, but the person you are calling has a voice mailbox that has not been set up yet.
Please try again later.
Bye Bye!
Answer:
bye bye
Explanation:
Answer: Or please call again to see if they reached the phone yet.
Explanation: It always stops ringing right before someone gets to there phone so call again in 2 minutes. :3
When a force is applied to a wheel, its axle exerts a greater force?
Answer:
That is true.
Explanation:
When the input force is applied to the wheel, as it is with a doorknob, the axle turns over a shorter distance but with greater force, so the mechanical advantage is greater than 1.
Momentum questions help
Answer:
a=25000 kg•m/s
b=1200 kg•m/s
c=what force?
Explanation:
for question a you multiply the mass which is 1000kg with velocity 25m/s.
for question b you multiply the force 60n with time 20s
Two people of equal mass attempt a tug-of-war with a 10 m long rope
while standing on ice. On pulling the rope, they both slide towards
each other. What will be the acceleration for each person?
Answer:
Explanation:
As the poster has noted above in comment, the acceleration for each person will be the same. This is because when they tugon the rope, there will be tension force on the rope pulling the two persons towards each other. The tension force will be the same for them. As they also have equal mass, by Newton's Second Law of Motion, Force = mass * acceleration, their acceleration will be the same.
An unbalanced force acting on an object will cause it
A. increase in mass
B. decrease in mass
C. accelerate
D. remain at rest
Three different scientific institutions provide data about how much the annual global temperature has deviated from the norm in the years 1880 to 2014. The nort is
based on the temperatures of a base period, from 1951 to 1980
Institution A's data show that the annual global temperature deviated from the norm by 0.75°C in 2010
Institution B's data show that the annual global temperature deviated from the norm by 0.72°C in 2010
Institution C's data show that the annual global temperature deviated from the norm by 0.77°C in 2010.
Which are accurate statements about this data? Select the two correct answers
(1 point)
Based on the findings above, the accurate statements are:
B. The institutions have not yet gathered enough data for scientists to draw a conclusion about whether the annual global temperature is gradually increasing.C. The data gathered by each institution is very similar to the data gathered by the other institutions.What are the accurate statements?The information that all three institutions gathered is quite similar with their results showing a range of annual temperature deviation of 0.05°C in 2010.
However, this data is not enough to say that temperatures are rising gradually because there is no information on temperatures from the previous years.
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Which of the following would NOT cause acceleration?
A. an object falling towards the earth
B. the wind catching the sail of a sailboat
C. a car traveling at a constant velocity
D. a pitcher throwing a baseball
On a dusty day clean polished shoes attrack alot of dust.Explain this?
Because when we polish the shoes, they gain charges or the shoes become charged, the small non-charged particles are attracted to them.