Answer:
A. Both melting and freezing are physical changes
Explanation:
A chemical reaction occurs when there are new properties but the water keeps being water whether it is freezed or liquid so is not a,c,d.
A physical change occurs when the substance changes its state but no its components or properties so is A is the correct answer.
The true statement is A. Both melting and freezing are physical changes because the substance's composition remains H2O, and only its state changes.
When ice melts to form water or water freezes to form ice, the physical state of water changes from solid to liquid or vice versa, but the composition of water remains the same. This means that the molecules are not changed chemically.
Melting is when a solid becomes a liquid by absorbing heat or ambient temperature increases, during which its shape can change, but its composition does not. Freezing is the reverse process, where a liquid turns into a solid as it loses heat. Both processes are reversible, meaning you can switch from one state to another without altering the chemical identity of the substance. This marks the key characteristic of a physical change.
How many paths do the electrons have to flowlin a series circuit?
Mimi makes a table about the two types of beta decay. A 5 column table with 2 rows. The first column is labeled type of decay with entries beta plus and beta minus. The second column is labeled particle released with entries positron and electron. The third column is labeled change to nucleus with entries proton changes to neutron and neutron changes to proton. The fourth column is labeled change to mass number with entries no change and decrease by 1. The last column is labeled change to atomic number has entries decrease by 1 and increase by 1. What error did Mimi make? No change in mass number occurs in beta minus decay. The changes to atomic number are reversed. A proton is released in beta plus decay. The changes to the nucleus are reversed.
Answer:
No change in mass number occurs in beta minus decay
Explanation:
Answer:
Explanation:
No change in mass number occurs in beta minus decay
The driver of a car slams on the brakes, causing the car to
slow down at a rate of 17ft/s2 as the car skids 175ft to a
stop.
How long does the car take to stop?
What was the car's initial speed?
It takes 4.58 seconds for the car to stop and the initial speed of the car is 77.14 ft/s
Explanation:
Given:
Acceleration, a = -17 ft/s²
Distance, s = 175 ft
Final velocity, v = 0
Time, t = ?
Initial speed, u = ?
We know:
v² - u² = 2as
(0)² - (u)² = 2 X - 17 X 175
u² = 5950
u = 77.14 ft/s
To calculate time:
v = u + at
0 = 77.14 - 17 X t
17t = 77.14
t = 4.58 sec
Therefore, It takes 4.58 seconds for the car to stop and the initial speed of the car is 77.14 ft/s
After the driver of a car slams on the brakes, which causes the car to stop after traveling 175 ft with a slow down rate of 17 ft/s², we have:
a) The car stops after 4.54 s.
b) The car's initial speed is 77.14 ft/s.
We can calculate the time at which the car stops with the following kinematic equation:
[tex] v_{f} = v_{i} + at [/tex] (1)
Where:
t: is the time =?
[tex] v_{i}[/tex]: is the initial velocity
[tex] v_{f}[/tex]: is the final velocity = 0 (the car stops)
a: is the acceleration = -17 ft/s² (the minus sign is because the car is slowing down its speed)
First, we need to find the initial velocity.
[tex]v_{i}^{2} = v_{f}^{2} - 2ad[/tex]
Where:
d: is the distance traveled = 175 ft
Then, the initial velocity is:
[tex]v_{i} = \sqrt{v_{f}^{2} - 2ad} = \sqrt{-2(-17 ft/s^{2})175 ft} = 77.14 ft/s[/tex]
Hence, the initial velocity is 77.14 ft/s.
Now, the time at which the car stops is (eq 1):
[tex] t = \frac{v_{f} - v_{i}}{a} = \frac{0 - 77.14 ft/s}{-17 ft/s^{2}} = 4.54 s [/tex]
Therefore, the car stops after 4.54 s.
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a bicycle and a truck are both moving at 10mph, explain which one has more momentum.
Answer:
The truck has more momentum
Explanation:
The truck has more momentum as its mass is heavier than the bicycle.
To calculate momentum the formula is
P=mv
If the mass is greater then the momentum will increase assuming the velocity is the same
Spaceship 1 and Spaceship 2 have equal masses of 300 kg. They collide. Spaceship 1's final speed is 2 m/s, and Spaceship 2's final speed 1 m/s in the same direction. What is their combined momentum?
A. 600 kg-m/s
B. 900 kg-m/s
C. 1,200 kg-m/s
D. 3 m/s
Aaron and Sam cover the same distance on foot at the speed of 8 km/hr and 6
km/hr. Find the distance covered by each one of them when one takes 15 minutes
longer than the other.
Answer:
6 km
Explanation:
speed of Aaron, v = 8 km/hr
speed of Sam, v' = 6 km/hr
time 15 min = 0.15 hr longer than the other
Let the distance covered by both of them is d.
Let the time taken by Aaron is t and the time taken by Sam is t + 0.25
use the formula of distance = speed x time
For Aaron:
d = 8 x t ..... (1)
For Sam:
d = 6 ( t + 0.25) ..... (2)
From (1) and (2)
8 x t = 6 (t + 0.25)
8 t = 6t + 1.5
2t = 1.5
t = 0.75 hour
So, the distance traveled by both is 8 x 0.75 = 6 km.
Your family decided to go to sea World in San Antonio this weekend. If it takes
your Dad 4 hours to drive to San Antonio, which is 252 miles away, what would be
your Dad's average speed?
A. 48 mph
C. 63 mph
B. 73 mph
D. 58 mph
Answer:
63 mph
Explanation:
252/4 is 63mi
What most likely caused geologists to accept Alfred Wegener’s theory?
A.
After 50 years, the theory became popular.
B.
All hypotheses become theories after a long period of time.
C.
It took scientists a long time to understand Wegener’s ideas.
D.
Evidence supporting the theory slowly accumulated.
Answer:
D. Evidence supporting the theory slowly accumulated
Explanation:
If a theory is accepted over time, it is because other theories were proved wrong and the other theory is accepted because evidence proved them right or wrong.
Answer:
D Evidence supporting the theory slowly accumulated. Is the right answer.
Explanation:If a theory is accepted over time, it is because other theories were proved wrong and the other theory is accepted because evidence proved them right or wrong.
Plese give brainliest
1) What happens to the energy carried in the transverse wave as the
amplitude increases? *
Answer:
energy increases, frequency increases
Explanation:
As the amplitude of a wave increases, so does the energy it carries, with the energy of a wave being proportional to the square of its amplitude. This relationship is true for various types of waves, including electromagnetic, mechanical, and sound waves. Doubling the amplitude of a wave results in a fourfold increase in its energy, highlighting a quadratic relationship.
What happens to the energy carried in the transverse wave as the amplitude increases? As the amplitude of a wave increases, the energy carried by the wave also increases. This principle applies to various types of waves, including sound waves, water waves, and electromagnetic waves. The relationship between a wave's energy and its amplitude is quadratic; meaning that if the amplitude of a wave is doubled, the energy it carries increases by a factor of four. This is because the energy of a wave is proportional to the square of its amplitude (E² or B²).
For instance, with electromagnetic waves, increasing the amplitude of the electric field (E) and magnetic field (B) results in a significant increase in both the energy density and the energy flux of the wave. This principle is also observed in mechanical waves, such as those on a guitar string or in the air as sound waves, where the amplitude of the wave is related to physical quantities like pressure.
The fact that the intensity of a wave increases fourfold with a doubling of amplitude might seem to challenge the conservation of energy. However, there's no violation occurring; rather, it's an inherent characteristic of wave behavior, allowing for greater energy transmission with increased amplitude.
Two pith balls hang side by side close to each other without touching as shown in the figure below. They are both neutral to begin with.
a.A plastic rod is rubbed with wool. Describe as negative, positive or neutral the total (net) charge of a system consisting of the rod and the cloth. Explain your reasoning.
b.A student touches sphere A briefly with the rod and then removes it. Then he brings the rod close to sphere A but does not touch it. What will happen to A? Explain your reasoning.
c.What is the charge state of the system consisting of the rod and wool now? Explain your reasoning.
d.Now sphere B is brought very close to A but does not touch it. What will happen to the spheres? Explain your reasoning.
e.Now the student touches sphere B with the same charged rod as above. What will happen to spheres A and B afterwards? Again, the spheres are close to each other but do not touch. Explain your reasoning.
f.What is the charge state of the system consisting of the rod and both spheres? Explain your reasoning.
g.Sphere B is now discharged. Then it is touched by a glass rod that was rubbed with silk. Now both spheres are brought close to each other. What will happen to the spheres now? Explain your reasoning.
h.Both spheres are now moved a bit further apart. What will happen to them now? Explain your reasoning.
a)
When a plastic rod is rubbed with wool, charging by friction occurs.
This is one of the three mechanisms of charging an object: in this particular case, as the rod is rubbed with the wool, electrons jump from the wool to the rod.
As a result, the plastic rod will remain with an excess of electrons (negative charge), while the wool will remain with a lack of electrons (positive charge).
However, the number of electrons gained by the rod is equal to the number of electrons given off by the wool: therefore, the total net charge of the system rod + cloth has not changed.
b)
When the rod touches sphere A, some electrons are transferred from the rod to the sphere (this method of charging is called charging by conduction).
Then, the sphere A will also remain negatively charged, as well as the plastic rod.
Later, the rod is brought close to sphere A without touching it: here, the electrons in the rod repel the electrons in the sphere (like charges repel each other), so the rod and the sphere will repel each other.
c)
Before part b), the negative charge on the plastic rod was equal to the positive charge on the wool.
After part b), the plastic rod has given off part of its electrons to sphere A. As a result, the negative charge on the plastic rod will be now less than the positive charge on the wool.
Therefore, the net charge of the rod + wool system will now be positive.
d)
The electrostatic force between two charged object is:
- Attractive if the charges on the objects have opposite sign
- Repulsive if the charges on the objects have same sign
Since sphere A is charged negatively, when it is brought close to sphere B, the electrons in sphere B will be attracted on the opposite side relative to sphere A, while the positive charges will migrate close to sphere A. Therefore, the two spheres will attract each other, since opposite charges attract each other.
e)
When the plastic rod (which is negatively charged) touches sphere B, some electrons are transferred to sphere B (charging by induction). As a result, charge B will also be negatively charged now, as it has an excess of electrons.
At the same time, sphere A is also negatively charged. Therefore, as like charges repel each other, this means that the two spheres will now repel each other.
f)
The net charge of the rod and the two spheres is negative.
In fact, the electrons given off by the rod to the two spheres were initially on the rod itself: this means that the total net charge of the rod + 2 spheres is equal to the net charge on the rod before the process.
Since the net charge on the rod before the process was negative, then the net charge of the system consisting of the rod + 2 spheres must be negative as well.
g)
When a glass rod is rubbed with silk, charging by friction occurs, similar to part a). However in this case, the glass rod gives off electrons to the silk: therefore, the glass rod remains positively charged.
Later, the glass rod touches sphere B: as a result, positive charge is transferred from the rod to sphere B, so sphere B will remain positively charged.
In the meantime, sphere A is negatively charged: since opposite charges attract each other, this means that now sphere A and sphere B will attract each other.
h)
When the two spheres are moved a bit further apart, the attractive force between them decreases a bit. In fact, the electrostatic force between two charged objects is given by
[tex]F=k\frac{q_1 q_2}{r^2}[/tex]
where
k is the Coulomb's constant
q1, q2 are the charges on the two objects
r is the separation between the objects
As we can see, the force is inversely proportional to the square of the distance: therefore, if the separation between the spheres increases, the force will decrease.
What do we call the substances that are formed as a result of substances reacting together?
Group of answer choices
A)none of the answers are correct
B)catalysts
C)products
D)reactants
8. When you see a stopped local bus (1 point)
you must stop if you are facing it.
you must stop if you are directly behind it.
wait for its lights to stop flashing.
be alert for pedestrians near the bus.
Answer: be alert for pedestrians near the bus.
Explanation: Due to road accidents many Governments around the world has adopted and put in place certain rules and regulations with regards to road safety, this is so to prevent the or reduce the chances of accidents happening.
Road safety rules are rules and guidelines put in place by Government in order to prevent road accidents and maintain a free flow of traffic. An example of such rules is 'be alert for pedestrians near the bus ' when approaching a local bus that is stopped.
What to do when you see a stopped local bus is;
Be alert for pedestrians near the bus.
This question is dealing with traffic rules as put in place by government to prevent unnecessary accidents and to enhance law and on the roads. Now, when one sees a stopped local bus, it is possible that the bus is stopping for pedestrians to cross if there is a zebra crossing there or trying to pick up passengers. Thus, it is very important for a driver to wait and see or in simpler terms be alert for the pedestrians crossing or entering the bus to avoid accident.Read more at; https://brainly.com/question/21760936
The diagram shows a heating curve for a substance. Which segment shows the substance changing from a gas to a liquid?
X-Y
Y-X
W-X
X-W
Answer:
Y-X
Explanation:
Answer:
B
Explanation:
ANSWERS PLEASEEEE
Three runners are jogging from North Augusta to Beech Island. Runner 1 runs 14 miles in 3 hours while Runner 2 runs 16 miles in 4 hours. Runner 3 runs 15 miles in 6 hours. What is the average speed of each runner? Then, get the average speed of all the runners together (total distance/total time)
Explanation:
Given that,
Runner 1 runs 14 miles in 3 hours. His average speed is given by :
[tex]v_1=\dfrac{14\ miles}{3\ h}=4.67\ mph[/tex]
Runner 2 runs 16 miles in 4 hours. His average speed is given by :
[tex]v_2=\dfrac{16\ miles}{4\ h}=4\ mph[/tex]
Runner 3 runs 15 miles in 6 hours. His average speed is given by :
[tex]v_3=\dfrac{15\ miles}{6\ h}=2.5\ mph[/tex]
Total distance covered by all three runners, D = 14 + 16 +15 = 45 miles
Total time taken, t = 3 + 4 + 6 = 13 hours
The average speed of all the runners together is given by :
[tex]V=\dfrac{45\ miles}{13\ h}\\\\V=3.46\ mph[/tex]
Hence, this is the required solution.
This type of wave behavior causes white to disperse into different colors when shun through a prism like the one picture above. *
4 points
Reflection
Refraction
Diffraction
Scattering
Answer:
Refraction
Explanation:
Refraction is a phenomenon typical of light waves. It occurs when a ray of light passes through the interface between two mediums: when doing so, the ray of light changes speed and also changes direction, according to Snell's Law:
[tex]n_1 sin \theta_1 = n_2 sin \theta_2[/tex]
where
[tex]n_1, n_2[/tex] are the index of refraction of the first and second medium, respectively
[tex]\theta_1, \theta_2[/tex] are the angle of incidence and refraction, respectively
When white light enters a prism, therefore, it undergoes refraction, and it changes direction.
However, the index of refraction of a material, n, depends also on the wavelength of the light. In particular, the shorter the wavelength, the higher the index of refraction.
This means that as white light enters a prism, the different wavelengths contained in the white light are refracted at different angles: as a result, the 7 colors of light will separate, and that is why we observe the rainbow when white light enters a prism.
A leaf electroscope is a device that indicates the existence of electric charge on an object. The leaves spread apart when an object is brought near or touches the electroscope. What observation would suggest that the object touched the electroscope?
Answer: the leaves remainined apart after the charged was removed
Explanation:
A wave with a speed of 54m/s travels through vulcanized rubber with a wavelength of 0.90 m. What is the frequency of this wave? *
4 points
80 Hz
50 Hz
60 Hz
0.017 Hz
Answer: 60Hz
Explanation:
Given that
Speed of wave V= 54m/s
Wavelength ( λ) = 0.90 m
Frequency of wave F = ?
Recall that the frequency of a wave is the number of cycles the wave complete in one secon, and it is measured in hertz.
So, apply the formula
V = F λ
F = V/ λ
F = 54m/s / 0.90 m
F = 60Hz
Thus, the frequency of this wave is 60 Hertz
An object's (mass or weight) will remain constant throughout the universe, but its (mass or weight) can change from planet to planet. If you increase the mass of a planet, what happens to its gravity? (Strength of gravity increases, strength of gravity decreases, strength og gravity stops completely) If the gravity on a planet decreases, what happens to the weight of an object on that planet? (Weight increases, weight decreases, weight stays the same)
Answer:
1: mass
2:weight
3: gravity increases
4: it decreases
Hope this helps:)
Explanation:
Answer:
Mass, Weight, Strength Increases, and Weight decreases
Explanation:
Got them right on Edge
If the light ray hits a mirror at a 40° angle (above picture), what angle will the ray of light be reflected? *
4 points
140°
40°
50°
90°
Answer:
40 degrees
Explanation:
The angle is reflected at the same degree.
You are driving a bus. When you begin your route, there is an old woman named Mrs. Smith and a young boy named Raymond are on the bus. At the first stop, the old woman leaves, and a salesman, named Ed, enters. At the next stop, Jack and his sister Jill get on, as well as three women with shopping bags. The bus travels fifteen minutes, then stops and Raymond gets off and a man and his wife get on. Next, a woman with a bird in a cage gets on the bus. What is the name of the bus driver?
Answer:
you are the bus driver
A child is playing with a spring toy, first stretching and then compressing it.
[T-2, C–5, A-1]
a) List the energy transformations taking place during this activity.
SPH4U – Unit Test (Energy & Momentum)
5 | P a g e
b) Is the force applied by child constant or variable? Give reason for your answer.
c) Draw a graph showing variation of the restoring forces developed inside the
given spring when it is stretched or compressed.
d) How this force is related to the force applied by the child?
When a child compresses a spring toy, potential energy is stored. When the spring is released, the potential energy transforms to kinetic energy. The force the child applies is variable and directly related to the restoring forces of the spring.
When a child plays with a spring toy, it experiences a Energy transformations of energy: kinetic energy to potential energy and vice versa.
When the child first compresses the spring, the child is doing work on the toy, and as a result, the spring stores potential energy.
When the spring is released, it transforms the stored potential energy to kinetic energy as it bounces back.
This is a demonstration of the law of conservation of energy as total energy is conserved in the system.
The force applied by the child is variable because it changes depending on whether the spring is being compressed or released.
The restoring forces developed inside the spring will be proportional to the displacement: F = -kx, where 'k' is the spring constant and 'x' is the displacement.
A graph of these forces would be a straight line passing through the origin, with the slope equal to 'k'.
The force applied by the child to compress or stretch the spring is directly related to the variable tension or compression forces in the spring which are responsible for its restoration back to its original shape.
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what would you expect to happen to the acceleration if all friction were removed from the ramp, making the net force even higher than 600n
Answer:
Increase
Explanation:
The acceleration will increase more if all the friction were removed from ramp.
Acceleration is the rate of change of velocity with time.
Frictional force is a force that opposes motion of a body.
A large friction will reduce the velocity of a body significantly and bring it to stop, a state of no acceleration. When friction is removed, the acceleration of a body will increase significantly since the velocity will change rapidly. At each turn of time, the velocity keeps increasing due to absence of the inhibiting force of friction.Answer:
If friction were removed from the ramp, the acceleration of the skateboarder will increase.
Explanation:
Troy pushes on a car for 7 seconds, during which he applies an impulse of
2000 kg•m/s. What force does he apply to the car?
Answer:
F=I/Δt
F=2000/7
F=285.7 N
Explanation:
Final answer:
Explanation:
The student is asking a physics question related to the concept of impulse and force. Impulse, represented by the product of force and time, is equivalent to the change in momentum of an object. The question involves calculating the force applied by Troy when he pushes on a car for 7 seconds, with a given impulse of 2000 kg·m/s.
To find the force applied, we use the formula for impulse: impulse = force × time. Thus, force can be calculated by dividing the impulse by the time over which the force is applied. Given that the impulse is 2000 kg·m/s and the time is 7 seconds, the force applied by Troy can be calculated as:
Force = Impulse / Time = 2000 kg·m/s / 7 s = 285.71 N
Therefore, the force Troy applies to the car is 285.71 Newtons.
Can you help me??? This is too hard.
Answer:
Vacuum. A sound vacuum was created, i believe.
What does hydroelectric power do?
A) releases carbon dioxide into the air
B) causes thermal pollution
C)requires building dams that can harm ecosystems
D)uses the energy inside an atom's nucleus to generate electricity
Answer: D
Explanation:
Answer:
D)uses the energy inside an atom's nucleus to generate electricity
Explanation:
it was on my reading passage
calculate the average speed of a car of it traveled 180km in 2.0hr
Answer:
1500m/s
Explanation:
d=180000
t=120
units have to be converted into SI Units
Average Speed = (Total distance)/(Total Time)
Average Speed= (180000)/(120)
Which of the following items are affected the most by the force of gravity?
A. A tennis ball
B. A golf ball
C. A baseball
D. A bowling ball
Answer:
Explanation:
I would say all of them are affected by gravity- everything on the planet of earth is affected by gravity it pushes everything back down, however, if I had to make a guess I would say baseball because there is more gravity applied to the force of the ball than there is used in any other game listed.
Answer:
The bowlingball because it is the heavest which will cause it to fall faster thus showing it is the most affected by gravity.
Explanation:
Objects 1 and 2 attract each other with a electrostatic force of 18.0 units. If the distance separating Objects 1 and 2 is changed to one-third the original value, then the new electrostatic force will be _____ units.
The new electrostatic force will be 9 times greater than the original force.
Explanation:Coulomb's law, a fundamental principle in electrostatics, describes the relationship between the force F between two point charges q₁ and q₂ separated by a distance r. It states that F is directly proportional to the product of the charges and inversely proportional to the square of the distance, mathematically expressed as F = k * (q₁ * q₂) / r², where k is the electrostatic constant.
According to Coulomb's law, the electrostatic force between two charged objects is inversely proportional to the square of the distance between them. If the distance between Objects 1 and 2 is changed to one-third the original value, the new electrostatic force will be 9 times greater than the original force.
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Light always follows one and the same path traveling back and forth. If a flashlight has a light bulb placed exactly in the focal point of its convex lens, it will produce a beam of..
A. converging light rays
B. diverging light rays
C. parallel light rays
Final answer:
When a light bulb filament is at the focal point of a convex lens, parallel light rays emerge. The convex lens refracts the light so that rays diverge within the lens and exit parallel, creating a focused beam used in devices like flashlights.
Explanation:
When a light bulb filament is placed at the focal point of a convex lens, the light rays that emerge from the other side are parallel light rays. This effect is due to the properties of convex lenses and their interaction with light. In a convex lens, parallel rays of light are refracted in such a way that they converge at the lens's focal point. Conversely, when a light source is placed at that focal point, the rays diverge within the lens, but then leave the lens parallel to each other. This phenomenon is utilized in various devices such as flashlights, lighthouses, and traffic lights to create a focused and directional beam of light. Option C
The science behind this involves the law of refraction, which dictates that light changes direction when it passes through materials of different densities, like air and glass. In the case of the convex lens, the curvature of the lens and its refractive properties cause the light rays from the focal point to exit parallel. This design ensures that the output beam spreads minimally, providing a strong, directional source of light.
A boy pedals his bicycle with a net horizontal force of 235 N. If the total mass of the boy and the bike is 40 kg, how much are they accelerating
Answer:
force=mass×acceleration
235=40×a235÷40=aa=5.875m/sThe boy and the bike accelerating at 5.875 m/s^2.
What is acceleration?Acceleration is rate of change of velocity with time. Due to having both direction and magnitude, it is a vector quantity. Si unit of acceleration is meter/second² (m/s²).
Given parameters:
Total mass of the boy and the bike : m = 40 kg.
Net horizontal force = 235 N.
Now according to Newton's 2nd law of motion:
Force = mass × acceleration
⇒ acceleration = Force /mass
⇒ acceleration = 235/40 m/s^2
⇒ acceleration = 5.875 m/s^2.
Hence, they are accelerating at 5.875 m/s^2.
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