Answer:Physical changes involve states of matter and energy.
Explanation:
No new substance is created during a physical change, although the matter takes a different form. The size, shape, and color of matter may change. Physical changes occur when substances are mixed but don't chemically react.
Final answer:
A physical change is when matter changes its form or properties without changing its chemical identity, such as melting ice or evaporating water.
Explanation:
A physical change is a type of change in which the form of matter is altered but its identity remains the same. For example, when an ice cube melts, it goes from a solid to a liquid (Figure 1.2.3); this change alters its shape and allows it to flow, yet the chemical composition of water (H₂O) does not change. Another instance is when water vaporizes; the temperature and energy of water molecules increase leading to evaporation, turning liquid water into water vapor (H₂O (l) → H₂O (g)), without altering the molecular structure.
Sorting a mixture of pennies and nickels changes the arrangement of the coins without changing their properties. Similarly, tearing a piece of paper changes its shape and size, but it remains paper. These examples show that during a physical change, the arrangement of particles may change, but the mass, number of atoms, and number of molecules stay the same.
Anna heated 15 g of Substance A to obtain 5 g of Substance B, 4 g of Substance C, and a certain amount of Substance D. Which statement is correct?
The mass of Substance D was 10 g less than the mass of Substance A.
The mass of Substance D was 1 g greater than the mass of Substance B.
The mass of Substance A was equal to the total mass of Substance C and Substance D.
The mass of Substance A was equal to the total mass of Substance B and Substance D.
Answer:
The mass of Substance D was 1 g greater than the mass of Substance B.
Explanation:
15 g of A → 5 g of B + 4 g of C + x g of D
From the law of conservation of mass, Mass of D should be x = (15 - 5 - 4 ) g = 6 g
This is 1 g more than the mass of B and 2 g more than mass of C.
Thus, correct option is The mass of Substance D was 1 g greater than the mass of Substance B.
significant digits show the _____ of measurements and calculations.
1) accuracy
2) precision
A car is traveling at 10m/s before it increases its speed to 30m/s for 120m. How long does it take to do this ?
Answer:
60 seconds
Explanation:
Given:
v₀ = 10 m/s
v = 30 m/s
Δx = 120 m
Find: t
Δx = ½ (v + v₀)t
120 = ½ (30 + 10) t
t = 60
It takes 60 seconds.
which system of government has a leader that takes power by force
Answer:
The Autocratic system of governance
Explanation:
This is because,in Autocratic system of governance decision making is done by only individual. And his/her decision is final.
Answer:
The Autocratic system of governance
Explanation:
pls how to solve this problem. help would be appreciated
Answer:
80 m/s
Explanation:
Given:
a = -5 m/s²
v = 0 m/s
Δx = 640 m
Find: v₀
v² = v₀² + 2a(x − x₀)
(0 m/s)² = v₀² + 2(-5 m/s²) (640 m)
v₀ = 80 m/s
What will happen to an object at rest if no unbalanced forces act on it,
according to Newton's First Law?
Explanation:
Newton's first law says that an object at rest stays at rest, and an object in motion stays in motion, until acted upon by an unbalanced force.
If there's no unbalanced force, then an object at rest will stay at rest.
What is gas pressure
Answer:
Pressure is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside.xplanation:
Answer:
Pressure is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than the outside.
Explanation:
A right triangle with the base labeled 40 meters and the height labeled 30 meters. The hypotenuse is a dotted arrow labeled R. What is the magnitude of the resultant vector? 10 meters 50 meters 1200 meters 2500 meters
Answer:
The magnitude of the resultant vector R is 50 meters ⇒ 2nd answer
Explanation:
The resultant vector is the vector sum of two or more vectors
If the two vectors perpendicular to each other, then the magnitude of
the resultant vector is the square root of the sum of their squares
If x and y are two vectors perpendicular to each other, then the
magnitude of its resultant vector R is:
→ [tex]R=\sqrt{x^{2}+y^{2}}[/tex]
Lets solve the problem
A right triangle with the base labeled 40 meters and the height labeled
30 meters
The hypotenuse is a dotted arrow labeled R
→ The base and the height of the right triangle are perpendicular
→ The hypotenuse is the resultant vector of them
Assume that x represents the base of the triangle and y represents the
height of it
By using the rule above
→ x = 40 m , y = 30 m
→ [tex]R=\sqrt{x^{2}+y^{2}}[/tex]
→ [tex]R=\sqrt{(40)^{2}+(30)^{2}}[/tex]
→ [tex]R=\sqrt{1600+900}[/tex]
→ [tex]R=\sqrt{2500}=50[/tex]
The magnitude of the resultant vector R is 50 meters
The number of neutrons is equal to the atomic number
O A True
B. False
Answer:false
Explanation:
The total number of the neutrons in a atom is the difference of mass number of the atom and its atomic number.
The number of neutrons is not equal to the atomic number. Thus the given statement is false.
What is atom?Atom is the smallest unit of the matter consist the positive charged nucleus and the electrons which moves around it. The atom can not be divided further.
The atom of a matter is made by three elements-
1) Neutron-Neutron is the element of atom, which has zero charge.2) Proton-Proton is the element of atom, which has positive charge.3) Electron-Electron is the element of atom, which has negative charge.The relation between the atomic number and neutrons-
The total number of the neutrons in a atom is the difference of mass number of the atom and its atomic number.
Thus total number of the neutrons in a atom is,
[tex]N=M-n[/tex]
Here, [tex]M[/tex] is the mass number of the atom and [tex]n[/tex] is the atomic number of it.
Thus, the number of neutrons is not equal to the atomic number. Thus the given statement is false.
Learn more about the atomic number here;
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In the periodic table of elements, what do all of the elements in group 2 have in common?
Answer:
The correct answer is chemical properties.
Explanation:
In a group, the chemical properties are very similar, because all the elements of the group have the same number of electrons in their last or last layers. The electronic configuration of its last layer is the same, varying only the period of the element. Alkaline earth metals are harder than alkaline metals, have brightness and are good electrical conductors; less reactive than alkalines, good reducing agents and form ionic compounds.
Have a nice day!
how much force would be needed to move a car with the mass of 100kg to an acceleration of 5m/s/s?
Answer:
500 newton force is needed to move a car of mass 100kg to an acceleration of 5m/s/s.
Explanation:
As we know from Newton's second law of motion that force= F = m×a
=> F = 100 × 5 = 500 N
Which of the following is a way that microwaves and x-rays are similar?
A. They both have technological uses.
B. They are both high energy waves,
C. They are both to be exposed to at high doses.
D. They are both used to transmit information.
(I’m between A and B)
Answer:
A
Explanation:
In my opinion I'm pretty sure it's A because WE DO use microwaves and x-rays as techonological uses.
Answer:
A
Explanation:
How are energy of motion and speed are related to each other?
The energy transferred is known as kinetic energy, and it depends on the mass and speed achieved. Kinetic energy can be transferred between objects and transformed into other kinds of energy.
3. A car drives horizontally off of a cliff that is 40 meters tall and lands 65 meters from the base of
the cliff. What was the initial velocity of the car?
Answer:
23 m/s
Explanation:
First, find the time it takes for the car to fall 40 meters.
y = y₀ + v₀ t + ½ at²
0 = 40 + (0) t + ½ (-9.8) t²
0 = 40 − 4.9 t²
t = 2.89 s
Next, find the velocity needed to travel 65 meters in that time.
x = x₀ + v₀ t + ½ at²
65 = 0 + v₀ (2.89) + ½ (0) (2.89)²
v₀ = 22.75 m/s
Rounding to two significant figures, the car's initial speed was 23 m/s.
A nonuniform, but spherically symmetric, distribution of charge has a charge density ρ(r) given as follows:
ρ(r)=ρ0(1−r/R) for r≤R
ρ(r)=0 for r≥R
where ρ0=3Q/πR3 is a positive constant.
Express your answer in terms of some or all of the variables r, R, Q, and appropriate constants.
Obtain an expression for the electric field in the region r≥R.
Obtain an expression for the electric field in the region r≤R.
Find the value of r at which the electric field is maximum.
Find the value of that maximum field.
Answer:
r ≥ R, E = Q / (4πR²ε₀)
r ≤ R, E = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / (4πr²ε₀)
Maximum at r = ⅔ R
Maximum field of E = Q / (3πε₀R²)
Explanation:
Gauss's law states:
∮E·dA = Q/ε₀
What that means is, if you have electric field vectors E passing through areas dA, the sum of those E vector components perpendicular to the dA areas is equal to the total charge Q divided by the permittivity of space, ε₀.
a) r ≥ R
Here, we're looking at the charge contained by the entire sphere. The surface area of the sphere is 4πR², and the charge it contains is Q. Therefore:
E(4πR²) = Q/ε₀
E = Q / (4πR²ε₀)
b) r ≤ R
This time, we're looking at the charge contained by part of the sphere.
Imagine the sphere is actually an infinite number of shells, like Russian nesting dolls. For any shell of radius r, the charge it contains is:
dq = ρ dV
dq = ρ (4πr²) dr
The total charge contained by the shells from 0 to r is:
q = ∫ dq
q = ∫₀ʳ ρ (4πr²) dr
q = ∫₀ʳ ρ₀ (1 − r/R) (4πr²) dr
q = 4πρ₀ ∫₀ʳ (1 − r/R) (r²) dr
q = 4πρ₀ ∫₀ʳ (r² − r³/R) dr
q = 4πρ₀ (⅓ r³ − ¼ r⁴/R) |₀ʳ
q = 4πρ₀ (⅓ r³ − ¼ r⁴/R)
Since ρ₀ = 3Q/(πR³):
q = 4π (3Q/(πR³)) (⅓ r³ − ¼ r⁴/R)
q = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴)
Therefore:
E(4πr²) = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / ε₀
E = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / (4πr²ε₀)
When E is a maximum, dE/dr is 0.
First, simplify E:
E = 12Q (⅓ (r/R)³ − ¼ (r/R)⁴) / (4πr²ε₀)
E = Q (4 (r³/R³) − 3 (r⁴/R⁴)) / (4πr²ε₀)
E = Q (4 (r/R³) − 3 (r²/R⁴)) / (4πε₀)
Take derivative and set to 0:
dE/dr = Q (4/R³ − 6r/R⁴) / (4πε₀)
0 = Q (4/R³ − 6r/R⁴) / (4πε₀)
0 = 4/R³ − 6r/R⁴
0 = 4R − 6r
r = ⅔R
Evaluating E at r = ⅔R:
E = Q (4 (⅔R / R³) − 3 (⁴/₉R² / R⁴)) / (4πε₀)
E = Q (8 / (3R²) − 4 / (3R²)) / (4πε₀)
E = Q (4 / (3R²)) / (4πε₀)
E = Q (1 / (3R²)) / (πε₀)
E = Q / (3πε₀R²)
For question 1:
For the region [tex]r \geq R[/tex], an expression for the electric field can be calculated by using the Gauss law:
Use gauss law of electrostatics, the charge electric flux through the Gaussian surface is,
[tex]\int \vec{E} \cdot d\vec{A}=\frac{q_{enc}}{\varepsilon_{0} }\\\\E(4\pi r^2)=\frac{Q}{\varepsilon_0}\ \ \ \ \ \ \ \ \ \ \ \ \ (Since\ \ q_{enc}=Q )[/tex]
Here, Q is the enclosed charge and [tex]\varepsilon_0[/tex] , is the permeability.
[tex]E=\frac{1}{4\pi \varepsilon_0 } \frac{Q}{r^2}[/tex]
Therefore, the required electric field is [tex]\frac{Q}{4\pi\varepsilon_0 r^2 }[/tex]
For question 2:
For Gaussian sphere of radius [tex]r \leq R[/tex], the charge enclosed within a spherical shell is,
[tex]dq =\rho_0(1-\frac{r}{R}) 4\pi r^2 dr[/tex]
Hence, the total charge enclosed with in the radius r is as follows,
[tex]q_{enc}=\int^{r}_{0} \rho_{0} (1-\frac{r}{R}) 4\pi r^2 \ dr\\\\[/tex]
[tex]=4\pi \rho_0 |\frac{r^3}{3}-\frac{r^4}{4R}|^4_{0}\\\\=\frac{12 Q}{R^3}(\frac{r^3}{3}-\frac{r^3}{4R})\\\\=\frac{Qr^3}{R^3}(4-\frac{3r}{R})\\\\[/tex]
Use Gauss's law for the Gaussian sphere of radius r,
[tex]\int \vec{E}\cdot dA=\frac{q_{enc}}{\varepsilon_0}\\\\E(4\pi r^2)=\frac{Qr^3}{\varepsilon_0 R^3}(4-\frac{3r}{R})\\\\E=\frac{Qr}{4\pi \varepsilon_0 R^3}(4-\frac{3r}{R})\\\\[/tex]
Therefore, the required electric field at [tex]r\leq R[/tex] is [tex]\frac{Qr}{4\pi \varepsilon_0 R^3}(4-\frac{3r}{R})\\\\[/tex]
For question 3:
The change in electric filed with respect to distance is zero when the electric field has a maximum value.
[tex]\frac{dE}{dr}= 0\\\\\frac{d(\frac{Qr}{4\pi \varepsilon_0 R^3}(4-\frac{3r}{R}))}{dr}=0\\\\(\frac{Q}{4\pi \varepsilon_0 R^3})\frac{d(4r-\frac{3r^2}{R})}{dr}=0\\\\[/tex]
Here, [tex](\frac{Q}{4\pi \varepsilon_0 R^3})[/tex] is not equal to zero. Hence,
[tex]\frac{d(4r-\frac{3r^2}{R})}{dr}=0\\\\4-\frac{6r}{R}=0\\\\r=\frac{4R}{6}=\frac{2R}{3}[/tex]
Therefore, the required value of [tex]r \ \ is\ \ \frac{2R}{3}\\\\[/tex]
For question 4:
Maximum value of the electric filed is as follows
[tex]E= \frac{Q}{4\pi \varepsilon_0 R^3} (4-\frac{3r}{R})\\\\[/tex]
[tex]= \frac{Q(\frac{2R}{3})}{4\pi \varepsilon_0 R^3} (4- \frac{3(\frac{2R}{3})}{R})\\\\=\frac{Q}{3 \pi \varepsilon_0 R^2}[/tex]
Therefore, the required maximum value of the electric field is [tex]\frac{Q}{3 \pi \varepsilon_0 R^2}[/tex]
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Hey:) what is a monatomic molecule?
Answer:
"mono" and "atomic" means single atom this term is used in both physics and chemistry and it applied to the gasses as a monatomic gas
Answer and Explanation:
Good Day mate!
A monatomic molecule is that some of the elements do not have a tendency to form a molecule. Which means, the molecule of an element is made up of only one atom. Thus, there are called as Monatomic molecule.
Some common examples of monatomic molecules :
1. Helium (He)
2. Neon (Ne)
3. Argon (Ar)
4. Xenon (Xe)
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? A right triangle overlaps a lake. It has sides 25 and 40 meters. Hypotenuse labeled L goes through the lake.
Answer:
The length of the swimming course is 47.16 meters.
Explanation:
It is given that the right triangle overlaps the lake and hypotenuse L runs through the length of the lake. Thus length of the lake will be the length of this hypotenuse.
The instructors have conducted measurements of the right triangle and has found the legs to be 25 and 40 meters. The sum of squares of base and height of a right triangle gives the value of its hypotenuse according to Pythagoras theorem.
Thus [tex]h^2+b^2=H^2[/tex]
b - base
h - height.
[tex]40^2+25^2=1600+625=2225[/tex]
[tex]H=\sqrt{2225}=47.16 m[/tex]
A sailor pulls a 2,000 kilogram boat 25 meters along the dock with a rope attached to the boat that makes a 45 degree angle with the dock. How much work is done by the sailor if he exerts a force of 400 newtons while pulling the boat?
Answer: 7071.067 Joules
Explanation:
The Work [tex]W[/tex] done by a Force [tex]F[/tex] refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path [tex]d[/tex].
It should be noted that it is a scalar, and its unit in the International System of Units is the Joule (like energy). Therefore, 1 Joule is the work done by a force of 1 Newton when moving an object, in the direction of the force, along 1 meter:
[tex]1J=(1N)(1m)=Nm[/tex]
Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:
[tex]W=(F)(d)[/tex] (1)
When they are not parallel, both directions form an angle, let's call it [tex]\alpha[/tex]. In that case the expression to calculate the Work is:
[tex]W=Fdcos{\alpha}[/tex] (2)
In this case the force and the distance in the path form an angle [tex]\alpha=45\°[/tex], so we will use the second equation, where [tex]F=400N[/tex] and [tex]d=25 m[/tex]:
[tex]W=(400 N)(25 m) cos(45\°)[/tex] (3)
Then:
[tex]W=7071.067 Nm=7071.067 J[/tex]
The work done by the sailor to pull the boat 25 meters with a force of 400 newtons at a 45-degree angle to the dock is approximately 7,071 Joules.
The amount of work done by the sailor on the boat can be calculated by using the formula for work done by a force at an angle, which is W = F imes d imes ext{cos}( heta). In this case, the force (F) is 400 newtons, the distance (d) is 25 meters, and the angle ( heta) is 45 degrees.
First, we calculate the cosine of the angle, which in this case is ext{cos}(45^{ ext{o}}) = rac{ ext{ extsqrt{2}}}{2}.
Then, we multiply the force, distance, and cosine of the angle: W = 400 N imes 25 m imes rac{ ext{ extsqrt{2}}}{2}.
Therefore, the work done by the sailor is 400 imes 25 imes rac{ ext{ extsqrt{2}}}{2}, which equals 7,071 Joules approximately.
An astronaut on spacewalk floats a little to far from space station without air to push against he can’t paddle back however he is holding a hammer explain how he could use the hammer to get him back to space station l
Answer:
The astronaut can throw the hammer in a direction away from the space station. While he is holding the hammer, the total momentum of the astronaut and hammer is 0 kg • m/s. According to the law of conservation of momentum, the total momentum after he throws the hammer must still be 0 kg • m/s. In order for momentum to be conserved, the astronaut will have to move in the opposite direction of the hammer, which will be toward the space station.
Explanation:found this as a verified answer on here
Answer:
He can throw the hammer in the direction opposite to the direction he wants to travel in. The hammer will exert an equal and opposite force on him, as per Newton's third law, and this will help him move towards the space station
Explane
above
I give a ball a push on an acclivity. The "start velocity" is on 7m/s. The time it took the ball to get back to me was 10 seconds. The acceleration is a constant. How much is the acceleration?
Answer:
7÷10
Explanation:
initial velocity=7m/s
final velocity=0m/s
Answer:
-1.4 m/s²
Explanation:
The initial velocity is 7 m/s. When the ball rolls back, its velocity is -7 m/s.
Acceleration is change in velocity over change in time.
a = Δv / Δt
a = (-7 m/s − 7 m/s) / 10 s
a = -1.4 m/s²
Bernoulli’s principle states that fluid velocity decreases when flow is restricted. True False
An object is thrown directly up (positive direction) with a velocity (vo) of 20.0 m/s and do= 0. How high does it rise (v = 0 cm/s at top of rise). Remember, acceleration is -9.80 m/s2.
d = _____ m
1.02
2.04
20.4
40.8
Answer:
20.4
Explanation:
Given:
y₀ = 0 m
v₀ = 20.0 m/s
v = 0 m/s
a = -9.80 m/s²
Find: y
v² = v₀² + 2a (y − y₀)
(0 m/s)² = (20.0 m/s)² + 2 (-9.80 m/s²) (y − 0 m)
y = 20.4 m
wavelength if the wave
Answer:
A what? Is this even a question?
Explanation:
????
can you help me??????????????????????????)?
Answer:
Velocity is a change in displacement over change in time and uses the units m/s.
Both are rates of change and can be positive or negative.
Acceleration is a change in velocity over change in time and uses the units m/s².
Explanation:
Velocity is the change in displacement over change in time, this makes it a rate of change. It can be positive or negative because it is a vector quantity. It uses the units m/s because that is a displacement unit over a time unit.
Acceleration is the change in velocity over change in time, this makes it a rate of change. It can be positive or negative because it is also a vector quantity. It uses the units m/s² (m/s/s) because that is a velocity unit over a time unit.
Gravitational pull is determined by
-the sun and stars
-acceleration and volume
-volume and mass
-mass and distance
Answer:
The gravitational pull is determined by the mass and distance.
Explanation:
According to Newton's law of universal gravitation
[tex]F = G\frac{m1.m2}{r^{2} }[/tex]
where F is the gravitational pull, G is gravitational constant, m₁ and m₂ are masses of bodies and r is the distance between them.
It can be seen from the above equation that F is directly proportional to the product of the masses and inversely proportional to the square of distance between them.
F ∝ m₁m₂
F ∝ 1/r²
A bulldozer does 4,500 J of work to push a mound of soil to the top of a ramp that is 15 m high. The ramp is at an
angle of 35° to the ground. How much force did the bulldozer apply to the mound of soil? Round your answer to two
significant figures.
Its 520 N
Answer:
520 N
Explanation:
Work is the dot product of the force vector and displacement vector.
W = F · x
This means it is the product of the magnitudes of the vectors and the cosine of the angle between them.
W = F x cos θ
The displacement of the soil is 15 m up. The force is parallel to the ramp. So the angle between the vectors is 90° − 35° = 55°.
Plugging in the values and solving for F:
4500 J = F (15 m) (cos 55°)
F = 523 N
Rounded to two significant figures, the force is 520 N.
what is the best description of a wave
A wave is a disturbance that travels through space and matter, characterized by its wavelength, frequency, and amplitude.
Explanation:A wave is a disturbance or oscillation that travels through space and matter, transferring energy from one place to another. Waves are characterized by three main features: wavelength, frequency, and amplitude. The wavelength is the distance between two identical points on successive waves. The frequency refers to the number of wave cycles that occur in a second. The amplitude is a measure of the wave's height from the rest position.
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How does the scattering of tiny particles in the air affect the colors of the sky at sunrise and sunset
It affects the colors of the sky at sunrise and sunset because only the longer-wavelengths colors are visible.
With which part of the brain is awareness typically associated?
Answer:cerebral cortex
Explanation:
Answer:
Cerebral Cortex
Explanation:
The cerebral cortex has a left and a right hemisphere. Each hemisphere can be divided into four lobes: the frontal lobe, temporal lobe, occipital lobe, and parietal lobe. The lobes are functional segments. They specialize in various areas of thought and memory, of planning and decision making, and of speech and sense perception.
Which of the following do you calculate
when you divide the total distance trav-
eled by the total travel time?