Angle of incidence always equals angle of reflection. Think of a tennis ball being hit into a wall. The ball will bounce off at the same angle that it approached with. The angles mentioned are formed through the line called the "normal", which is the line perpendicular to the surface.
Which of the following pure elements exist as liquids at normal Earth temperatures?
Answer:
The only liquid elements at standard temperature and pressure are bromine (Br) and mercury (Hg).
What does it mean for a system to be in dynamic equilibrium? (2 points)
Select one:
a. The rate of the forward reaction equals the rate of the backward reaction.
b. The concentration of products decreases.
c. The overall rate of the reaction slows down.
d. The temperature of the system is stable.
Answer:
A
Explanation:
A dynamic equilibrium is a chemical equilibrium between a forward reaction and the reverse reaction where the rate of the reactions are equal.
The rate of the forward reaction equals the rate of the backward reaction.
For a system to be in dynamic equilibrium, the forces should be balanced.
What is dynamic equilibrium?According to chemistry, Dynamic equilibrium is all about the equal rate of change in reactants and products, i.e., there will be a steady state. Also in Physics, if though the number of the composition of mixtures happens and that does not change with time, i.e., it is equilibrium constant. For example, when the car moving on the road, there will be some friction. The forward force of the car happened due to friction but no other force has changed at car's constant speed. When the net force will be same then it is known to be dynamic equilibrium.
Equilibrium constants can be determined as rate constants through reversible reaction, i.e., the rate of the forward reaction equals to the rate of the backward reaction.
Thus, option A is correct.
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What will be the pressure exerted by the object if 5000N of the force is acting on an area of 200 cm square
A boat floats south on the Amazon River at a speed of 6 m/s. The boat and
passengers have a combined mass of 540 kg.
a. What is the momentum of the boat? (Remember, momentum is a vector
quantity.)
b. The passengers paddle backward, reducing the speed to 4 m/s. What was the
impulse applied to the boat by the paddling?
Explanation:
Take south to be negative.
a. Momentum is mass times velocity.
p = mv
p = (540 kg) (-6 m/s)
p = -3240 kg m/s
p = 3240 kg m/s south
b. Impulse = change in momentum
J = Δp
Since the mass is constant:
J = mΔv
J = (540 kg) (-4 m/s − (-6 m/s))
J = 1080 kg m/s
J = 1080 kg m/s north
Which statement best describes monsoons? They force cool, moist air from oceans to rise. They are winds that blow in the opposite direction of a normal wind. They bring heavy rain in the winter and in the summer. They influence precipitation as wind moves near a mountain.
Answer:
They are winds that blow in the opposite direction of a normal wind
Explanation:
Answer:
B.) They are winds that blow in the opposite direction of a normal wind.
Explanation:
it's correct trust
You are in a desert on a hot day and see water in the distance. It is not really there, you see it because light bends due to a difference in the temperature of air. Which behavior of light best explains this? Select one: a. reflection b. translocation c. diffraction d. refraction
Answer:
d) refraction
Explanation:
in physics, refraction is the change of direction of a wave passing from one medium to another. refraction of light is the most commonly observed phenomenon but other waves such as sound waves and water waves also experience refraction
Answer:
B. Translocation
Explanation:
It means a change in location. It often refers to genetics, when part of a chromosome is transferred to another chromosome, you want a change in location because you are so thirsty in the desert and need water
Which statement is accurate about mass or weight? A. Mass can be measured in newtons. B. Weight can be measured in pounds. C. A bowling ball has the same mass as a golf ball. D. Objects have the same weight regardless of where they are.
Answer:
Option B
Explanation:
Weight can be measured in pounds. Pounds is a unit of weight.
=> Mass is measured in kgs
=> A bowling ball has more mass than a golf ball.
=> Objects do not have the same weight regardless of where they are. The weight depends on where they are as it depends on the acceleration due to gravity (g)
Answer:
B
Explanation:
Which of the following scientists introduced the concept of absolute zero?
A.lord kelvin
B.edwin Hubble
C.jonhannes kelper
D. Albert Einstein
Answer:
A. lord kelvin
Explanation:
In 1848, Kelvin used this as a basis for an absolute temperature scale. He defined "absolute" as the temperature at which molecules would stop moving, or "infinite cold." From absolute zero, he used the same unit as Celsius to determine the increments.
Absolute zero cannot technically be achieved. However, scientists have been able to lower the temperature of matter to just a fraction of a Kelvin above absolute zero through techniques such slowing down particles using lasers.
what are the physical changes on water
When very electronegative atoms, like oxygen, bond to atoms with a lower
electronegativity, like hydrogen, what's the result?
O A. The oxygen atom becomes strongly positive.
O B. The oxygen atom becomes strongly negative.
O C. The hydrogen atom becomes partially positive.
O D. The hydrogen atom becomes partially negative.
Answer:
Explanation:
B the oxygen atom becomes strongly positive
and
C HE HYDROGEN ATOM BECOMES PARTIALLY POSITIVE
PLS MARK MY ANSWER AS THE BRANLIEST
Help me please, it's so hard
Answer:
4.58×10²³ atoms
5.94×10⁻²¹ J
1340 m/s
Explanation:
Use ideal gas law to find moles of gas.
PV = nRT
(1.266 atm × 101300 Pa/atm) (4/3 π (0.15 m)³) = n (8.31451 J/mol/K) (14 + 273) K
n = 0.760 mol
Use Avogadro's number to find number of atoms.
(0.760 mol) (6.02214×10²³ atom/mol) = 4.58×10²³ atoms
Average kinetic energy per molecule is:
KE = 3/2 kT
KE = 3/2 (1.38066×10⁻²³ J/K) (14 + 273) K
KE = 5.94×10⁻²¹ J
RMS speed of each atom is:
KE = 1/2 mv²
5.94×10⁻²¹ J/atom = 1/2 (0.004 kg/mol) (1 mol / 6.02214×10²³ atom) v²
v = 1340 m/s
0
Which of the following can you conclude about a particle labeled
Check all that apply.
O A. It has one electron.
OB. It has one neutron.
I C. It has one nucleon.
O D. It has one proton.
E. It is negatively charged.
OF. It is an alpha particle.
O G. It is a beta particle.
Answer:
B and C
Explanation:
The given symbol [tex]_{-1}^{0}e[/tex] denotes an electron. An electrons has neglecting mass and has one unit of negative charge. Thus, option A is correct.
What is an electrons?An electron is a subatomic particle. the other subatomic particles that constitutes an atom are neutrons and protons. neutrons and protons are located inside the nucleus and electrons are revolving around the nucleus through circular paths of fixed energies.
Electrons are having negative charge and protons are positively charged particles. For an atom the number of protons and electrons are the same. Therefore, an element in its atomic state is neutral.
Neutrons are neutral. However both neutrons and protons are having significant mass compared to an electrons. Hence, the representation of electrons include zero mass and -1 charge. Hence, option A is correct.
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What has resulted in significant climate changes?
A. Plate tectonics
B. Doppler effects
C. Water pollution
Answer:A
Explanation:glass window allow light in but trap the heat inside
Research and discuss the aurora borealis in
terms of electric charges, magnetic fields,
and forces. Which times of the year are best
for seeing the northern lights, and where are
the best places to view them? Explain your
answers. Also identify links to good images. If
you've ever seen the aurora borealis,
describe your experience and note the time
and place that you saw it.
Answer: the best times to see it would be from 10 pm to 1 am, meaning when the night skies are dark and clear. The best months to see it would be from April to late August. Whereas the best places in the world to view them would be closer to the arctic circle, this includes Canada, Alaska, Iceland and Greenland.
Explanation:
Hope this helps
Auroras are created by disruptions in the magnetosphere induced by the solar wind. The greatest times to see it are between 10 p.m. and 1 a.m.
What is aurora borealis?Auroras are created by disruptions in the magnetosphere induced by the solar wind. The paths of charged particles in the magnetospheric plasma are altered as a result of these disruptions.
These particles, primarily electrons, and protons fall to the upper atmosphere.
The greatest times to see it are between 10 p.m. and 1 a.m. when the night skies are dark and clear. It is recommended to visit between April and late August.
The greatest spots to see them are closer to the arctic circle, which encompasses Canada, Alaska, Iceland, and Greenland.
Hence the greatest times to see it are between 10 p.m. and 1 a.m.
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Peter, a 100 kg basketball player, lands on his feet after completing a slam dunk and then immediately jump up again to celebrate his basket. When his feet first touch the floor after the dunk,
his velocity is 5 m/s downward; when his feet leave the floor 0.50 s later, as he jumps back up,
his velocity is 4 m/s upward. What is the average reaction force exerted upward by the floor on Peter during this 0.50 s?
Answer:
1800 N
Solution:
Impulse = mΔv = m * (u - v) .
here m = 100 kg
u = 4 m/s
v = -5 m/s
impulse = 100 x ( 4 - ( -5 ) ) = 900 Kg m/s .
Average reaction Force ( Favg ) = impulse / Δt
Average reaction Force ( Favg ) = 900kg·m/s / 0.5s
Average reaction Force ( Favg ) = 1800 N
Plz help me with question 3
Answer:
C. 110 - 140
Explanation:
Answer:
i think the best answer is c
Help me please savior
Answer:
-16°C
Explanation:
PV = nRT
V and n are constant.
P / T = P / T
(2 atm + 1 atm) / (266 K) = (1.9 atm + 1 atm) / T
T = 257.1 K
T = -16°C
A magnifying glass uses a convex lens of focal length 5.25 cm. When it is held 5.00 cm in front of an object, what magnification does it create? pls help
Answer:
21
Explanation:
A graduated plank of length 90cm sits on a knife edge at 40cm mark. When a load of 50g is placed at 20cm, find the mass that will balance the plank at 70cm length.
Answer:
33.3 g ≈ 33 g
Explanation:
Please see attached photo for explanation.
From the attached photo, M is the mass that we must obtain to balance the plank.
The mass, M can be obtained as follow:
Anticlockwise moment = clockwise moment
Anticlockwise moment = 50 x 20
Clockwise moment = M x 30
Anticlockwise moment = clockwise moment
50 x 20 = M x 30
Divide both side by 30
M = (50 x 20)/30
M = 33.3 g ≈ 33 g
Therefore, the mass that will balanced the plank at the 70 cm length is appropriately 33 g
What three colors can be combined to produce any color within the visible spectrum
Answer:
red, green, and blue.
Explanation:
The primary colors of light that combine to produce any color within the visible spectrum are red, green, and blue.
in the diagram, q2 is +34.4*10^-6 C, and q3 is -72.8*10^-6 C. The net force on q2 is 225 N to the right. What is q1? Include the sign of the charge (+ or -). PLS HELP
Answer:
q₁ = -6.54 10⁻⁵ C
Explanation:
Force is a vector quantity, but since all charges are on the x-axis, we can work in one dimension, let's apply Newton's second law
F = F₁₂ + F₂₃
the electric force is given by Coulomb's law
F = k q₁q₂ / r₁₂²
let's write the expression for each force
F₂₃ = k q₂ q₃ / r₂₃²
F₂₃ = 9 10⁹ 34.4 10⁻⁶ 72.8 10⁻⁶ / 0.1²
F₂₃ = 2.25 10³ N
F₁₂ = k q₁q₂ / r₁₂²
F₁₂ = 9 10⁹ q₁ 34.4 10⁻⁶ / 0.1²
F₁₂ = q₁ 3,096 10⁷ N
we substitute in the first equation
225 = q₁ 3,096 10⁷ +2.25 10³
q₁ = (225 - 2.25 10³) / 3,096 10⁷
q₁ = -6.54 10⁻⁵ C
a ball is projected with a certain angle with initial velocity u. it covers horizontal range R. With what initial velocity it must be projected keeping the angle of projection same so its horizontal range becomes 2.25R
Answer:
1.5 u
Explanation:
The range equation is:
R = u² sin(2θ) / g
When u = v, R = 2.25 R.
2.25 R = v² sin(2θ) / g
2.25 u² sin(2θ) / g = v² sin(2θ) / g
2.25 u² = v²
1.5 u = v
What is the mathematical equation for calculating the internal energy of a
diatomic gas?
-
Answer:
U = 5/2 NkT.
Explanation:
A diatomic molecule = H₂, O₂, N₂ .....etc
A diatomic molecule has 5 degrees of freedom.
3 transnational modes = x, y, z2 rotational modes = ωx , ωySo, the internal energy for diatomic gases is :
U = 5/2 NkT.
Which is equal to a temperature of 20°C?
20°F
68°F
36°F
32°F
A temperature of 20 degree Celsius is equal to 68 degree Fahrenheit temperature. Therefore, option b is correct.
What are temperature units ?Temperature is a physical unit which measures the overall heat of an object. The SI unit of temperature is Kelvin (K) and the commonly used unit is degree Celsius (°C).
Other unit of temperature is Fahrenheit (°F). These units can be interconverted between each other with the specific relation between them.
We know that zero degree Celsius is 32 Fahrenheit . Let T be the temperature in degree Celsius,
then, (T° × 9/5) + 32 = T in °F.
Given, temperature = 20 °C.
This temperature can be converted to °F as follows:
(20 °C × 9/5) + 32 = 68 °F.
Therefore, 20 °C is equal to a temperature of 68 °F.
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help me pls help me pls
Answer:
a ) 19,536.72 J,
b ) ( About ) 84°C
Explanation:
a ) We can solve this problem assuming that the dishwater remains a constant 78°C the entire duration.
Q = mass of the glass [tex]*[/tex] specific heat of the glass
The mass of the glass is given by 401 g, the specific heat by 840 J / kg [tex]*[/tex] C. Respectively the change in temperature would be the difference between the temperature of the dishwater, and that of the glass. As we want the units in Joules, we need to first convert the 401 g ⇒ kilograms.
401 g = 401 / 1000 kg = 0.401 kg,
Q = 0.401 kg [tex]*[/tex] 840 J / kg 19,536.72 J
b ) We know that the specific heat capacity of water is 4.184 J / g [tex]*[/tex] C. As the final temperature will be common between each substance, we can make their respective heat absorbed, the same. Note that the heat capacity is given in J / g
0.023 kg = 0.023 [tex]*[/tex] 1000 = 23 g,
0.18 kg = 180 g
[tex]- ( 180 )( 4.184 )( x - 93 ) = 23( 4.184 )( x - 14 )[/tex],
[tex]-753.12x+70040.16=96.232x-1347.248[/tex],
[tex]-753.12x=96.232x-71387.408[/tex],
[tex]-849.352x=-71387.408[/tex],
[tex]\frac{-849.352x}{-849.352}=\frac{-71387.408}{-849.352}[/tex],
[tex]x=84.04926\dots[/tex]
The final temperature will be about 84°C
Please help, I need you, please help me
Answer:
14 mL
Explanation:
Ideal gas law:
PV = nRT
If n is constant, then:
PV / T = PV / T
(0.819 atm) (17.9 mL) / (273 + 28) K = (0.99 atm) V / (273 + 13) K
V = 14 mL
PLS ANSWER REALLY EASY! WILL MARK BRAINLIEST.
State 4 differences (at least 3) between period and groups in the periodic table
Explanation:
They are;
The vertical columns of periodic table is called group and the horizontal rows of periodic table is called periods.The valance electron of all elements in the same group are the same but in periods the valance electron of elements in the same period increases from left to righr.The size of atoms increases top to bottom. but in case of periods the size of atoms decreases from left to right.Metalic reactivity increases and non metalic reactivity decreases from top to bottom. but in periods metalic reactivity decreases and non metalic reactivity increases from left to right.hope it helps...
At summer camp, the swimming course runs the length (L) of a small lake. To determine the length of the course, the camp counselors measure the two "dry" legs of a right triangle. What is the length in meters of the swimming course in the figure below?
Answer:
47 m
Explanation:
Data obtained from the question include the following:
Length of dry leg 1 (L1) = 40 m
Length of dry leg 2 (L2) = 25 m
Length of swimming course (L) =..?
The length of the swimming course can be obtained by using pythagoras theory as shown below:
L² = L1² + L2²
L² = 40² + 25²
L² = 1600 + 625
L² = 2225
Take the square root of both side.
L = √2225
L = 47.1 ≈ 47 m
Therefore, the length of the swimming course is approximately 47 m.
Two solid marbles A and B with a mass of 3.00 kg and 6.50 kg respectively have an elastic collision in one dimension. Before collision solid marble A (3.00 kg) was at rest and the other solid marble (6.50 kg) had a speed of 3.50 m/s. Calculate the magnitudes of velocities of two solid marbles vA and vB after collision.
Answer:
va = 4.79 m/s
vb = 1.29 m/s
Explanation:
Momentum is conserved:
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
(3.00) (0) + (6.50) (3.50) = (3.00) v₁ + (6.50) v₂
22.75 = 3v₁ + 6.5v₂
For an elastic collision, kinetic energy is conserved.
½ m₁u₁² + ½ m₂u₂² = ½ m₁v₁² + ½ m₂v₂²
m₁u₁² + m₂u₂² = m₁v₁² + m₂v₂²
(3.00) (0)² + (6.50) (3.50)² = (3.00) v₁² + (6.50) v₂²
79.625 = 3v₁² + 6.5v₂²
Two equations, two variables. Solve with substitution:
22.75 = 3v₁ + 6.5v₂
22.75 − 3v₁ = 6.5v₂
v₂ = (22.75 − 3v₁) / 6.5
79.625 = 3v₁² + 6.5v₂²
79.625 = 3v₁² + 6.5 ((22.75 − 3v₁) / 6.5)²
79.625 = 3v₁² + (22.75 − 3v₁)² / 6.5
517.5625 = 19.5v₁² + (22.75 − 3v₁)²
517.5625 = 19.5v₁² + 517.5625 − 136.5v₁ + 9v₁²
0 = 28.5v₁² − 136.5v₁
0 = v₁ (28.5v₁ − 136.5)
v₁ = 0 or 4.79
We know v₁ isn't 0, so v₁ = 4.79 m/s.
Solving for v₂:
v₂ = (22.75 − 3v₁) / 6.5
v₂ = 1.29 m/s
A boy on a chairlift moving parallel to the mountain slope at a speed of +15 m/s watches a skier going straight down the mountain with a speed of -35 m/s. What is the velocity of the skier relative to the chairlift? A. -50 m/s B. -35 m/s C. -20 m/s D. +15 m/s E. +50 m/s
Answer:
A. -50 m/s
Explanation:
Given
Velocity of Chairlift = +15m/s
Velocity of Skier = -35m/s
Required
Determine the velocity of the skier relative to the chairlift
Basically, relative velocity is the difference between the two velocities;
Having said that;
Relative velocity of the skier relative to the chairlift = Velocity of the Skier - Velocity of the Chairlift
Relative velocity of the skier relative to the chairlift = -35m/s - (+15m/s)
Open bracket
Relative velocity of the skier relative to the chairlift = -35m/s - 15m/s
Relative velocity of the skier relative to the chairlift = -50