Answer:
i believe its True
Explanation:
Select the correct answer.
Why does ice float on water?
A.
The temperature of ice is lower than the temperature of water.
B.
The temperature of water and ice are the same.
C.
The density of ice is less than the density of water.
D.
The density of ice is greater than the density of water.
Answer:
C.
The density of ice is less than the density of water.
The ice float on water because the density of ice is less than the density of water.
What is Density?The density of a material describes how dense it is in a given area. A substance's density is determined by its mass per unit volume. Density is essentially a measure of how tightly something is packed.
It is a particular physical quality of a specific thing. Discovering the density principle was done by the Greek scientist Archimedes. If you are familiar with the formula and the required units, calculating density is simple. Alternatively to the symbol, the letter D can be used to denote density.
ρ=m/v where,
ρ is the density,
m= mass of object and,
v is the volume of the object.
Hence, the density of ice is 917 kg/m³, which is less than the density of water which is 997.7 kg/m³ and due to this reason the ice floats on water.
To get more information about density :
https://brainly.com/question/15164682
#SPJ2
Alan walked 6.8 kilometers to his friend’s house. What is the distance in meters?
Answer:
6.8 kilometers= 6800 meters
Explanation:
1 kilometer= 1000 meters
A longitudinal wave moves energy that is to the direction of the wave’s movement.
Answer:
In longitudinal waves, the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave. Mechanical longitudinal waves are also called compressional or compression waves because they produce compression and rarefaction of a medium when traveling through the medium. They are also called pressure waves, because they produce increases and decreases in pressure of the medium. Sound waves is an example of longitudinal wave.
Answer:
parallel
Explanation:
i got it right on the test :)
What is it called when an atom can pass electrons?
Answer:
Ionic bonding.
Explanation:
According to our crude, conceptual definition, chemical bonds can form either by electron transfer between atoms or by sharing of electrons. ... When atoms lose or gain electrons, they become what are called ions. Loss of electrons leaves an atom with a net positive charge, and the atom is called a cation.
Hope this helped!
An object travels 40 m in 4 s and then another 50 m in 5 s .What is the average speed of the object?
Answer:
10m/sExplanation:
Average speed is the change in distance of a body/object with respect to time. Speed is expressed by the expression;
Speed = [tex]\frac{change\ in\ distance}{change\ in\ time}[/tex]
speed ΔV = ΔS/Δt
ΔV = S₂-S₁/t₂-t₁
given S₂ = 50m, S₁ = 40m, t₂ = 5s, t₁ = 4s
average speed = 50-40/5-4
average speed = 10/1
average speed = 10m/s
average speed of the object is 10m/s
If a light wave moves from water into seawater in which direction will the bend?
Answer:
Explanation:
The refractive index of sea water is more than refractive index of water . so when light passes from water to sea water or from low refractive index to high refractive index , ray of light bends towards the normal . This bending is very small because the difference in refractive index is very small.
using 15 percent as machine energy efficiency, what is the actual work output if the total work input is 7500 kilojoules?
A. 500 kilojoules
B. 750 kilojoules
C. 1,125 kilojoules
D. 7,500 kilojoules
Answer:
The actual work output is 1,125 kilojoules.
Explanation:
Energy efficiency is defined as the efficient use of energy. An appliance, process, or facility is energy efficient when it consumes less than the average amount of energy to perform an activity. Then, energy efficiency is the ratio between the amount of energy used in an activity and the amount expected to be carried out.
Efficiency is calculated as:
efficiency = output / input
Where output is the amount of mechanical work (in watts) or energy consumed by the process (in joules), and input (input) is the amount of work or energy that is used as input to carry out the process.
In this case:
Efficiency always has a value between 0 and 1. In this case, efficiency=0.15output=?input= 7500 kilojoulesReplacing:
0.15=output/7500 kilojoules
Solving:
Output=0.15* 7500 kilojoules
output=1,125 kilojoules
The actual work output is 1,125 kilojoules.
What are the three components of the equation for the second law of motion?
force= mass × acceleration
What class lever is a
1.Pencil Sharpener
2.Tennis racket
3. Hole puncher
4. Can opener
should be 1
Explanation:
because what do you use in class and has a lever
Is the formular of preasure P=F÷A
Answer:
yes the formula of pressure is P = F/A
Answer:
yes it is
Explanation:
The breaking car had 10,000 J of kinetic energy before breaking after breaking it had 2000 J of kinetic energy. How much thermal energy did the brakes gain?
Answer:
8000J
Explanation:
The kinetic energy of the car lost during breaking are converted to thermal energy and are gained by the brakes.
Kinetic energy loss by car = thermal energy gained by brakes.
∆K.E = ∆T.E ....1
The Kinetic energy loss by car can be expressed as;
∆K.E = K.E1 - K.E2
Initial K.E = K.E1 = 10000J
Final K.E = K.E2 = 2000J
∆K.E= 10000J - 2000J = 8000J
From equation 1,
∆K.E = ∆T.E
∆T.E = 8,000J
thermal energy gain by brakes = 8,000J
if an object in motion, experiences a net zero unbalanced force, the the body
1) will always remain at rest
2) cannot remain at rest
3) can be accelarated
4) moves with constant velocity
please choose the suitable option and give an explanation (not necessary) .
Answer:
4) moves with constant velocity
Explanation:
If an object is in motion, three things can happen:
1. The object slows down in speed.
This means a net force is needed to be able to slow the object down in speed.
2. The object increases in speed.
This means a net force is needed to be able to increase the speed of the object.
3. The object remains in motion at the same speed.
No net zero unbalanced force is needed.
This is the given situation. So this is the right answer.
Why do people get sunburned by UV light ?
Answer: Lack of melanin in the skin.
Explanation: The amount of melanin in your body is determined genetically. Some people dont produce enough melanin to protect their skin well. Eventually the UV causes the skin to burn, causing redness, swelling and pain.
PLEASE RATE 5 STARS AND VOTE AS BRAINLIEST:)
(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)(^o^)
To complete a project, 200,000 Joules of work is needed. The time taken to complete the project is 20 seconds. How much power is needed?
Answer:
10,000
Explanation:
200,000/20 = power needed
200,000/20 = 10,000
Hope this Helps!
Answer:
10,000 Watts
Explanation:
Power is the ratio of work to time, or work over time. It can be found using the following formula.
p=w/t
where p is the power, w is the work, and t is the time.
The project needed 200,000 Joules, and it took 20 seconds to complete the project. Therefore, w=200,000 and t=20. Substitute these values into the formula.
p=200,000/20
Divide
p=10,000
Add appropriate units. The units for power is Watts.
p=10,000 Watts
10,000 Watts of power is needed.
Answer these please.
Explanation:
hope this helps you
..........
Information about conservation of energy
Explanation:
Energy conservation is the effort made to reduce the consumption of energy by using less of an energy service. This can be achieved either by using energy more efficiently (using less energy for a constant service) or by reducing the amount of service used (for example, by driving less). Energy conservation is a part of the concept of Eco-sufficiency. Energy conservation reduces the need for energy services and can result in increased environmental quality, national security, personal financial security and higher savings.It is at the top of the sustainable energy hierarchy. It also lowers energy costs by preventing future resource depletion.
Energy can be conserved by reducing wastage and losses, improving efficiency through technological upgrades and improved operation and maintenance. On a global level energy use can also be reduced by the stabilization of population growth.
Energy can only be transformed from one form to other, such as heat energy to motive power in cars, or kinetic energy of water flow to electricity in hydroelectric power plants. However machines are required to transform energy from one form to other. The wear and friction of the components of these machine while running cause losses of very high amounts of energy and very high related costs. It is possible to minimize these losses by adopting green engineering practices to improve life cycle of the components.
Hope this helps u ......Explanation:
An electron in a mercury atom jumps from level a to level g by absorbing a single
photon. Determine the energy of the photon in joules.
Answer:
7.39ev
Explanation:
Energy levels are found inside the atom. Electrons occupy these energy levels depending on the energy they possess. Electrons can move from one energy level to another due to absorption or emission of a photon or other factors. As the electron, jumps from a higher energy level to a lower energy level emitting a photon of measurable frequency, the photon carries energy equal to the amount of energy between the gap of the levels. This idea was first proposed by Neils Bohr and became the forerunner of the wave mechanical model of the atom.
Hence the energy of a photon is the energy of the gap between the two energy levels. Since Ea= 2.48ev and Eg= 10.38 ev.
If an electron jumps from Ea to Eg, the energy of the photon absorbed is given by;
E=Eg-Ea
E= 10.38ev - 2.48ev
E= 7.39ev
Se golpea una pelota de golf de manera que su velocidad inicial forma un ángulo de 45° con la horizontal. La pelota alcanza el suelo a 180 metros del punto en que se lanzó. Calcula su velocidad inicial y el tiempo que ha Estado en el aire
Answer:
42m/s
6.06s
Explanation:
To find the initial velocity and time in which the ball is fling over the ground you use the following formulas:
[tex]x_{max}=\frac{v_o^2sin(2\theta)}{g}\\\\x_{max}=vt_{max}[/tex]
θ: angle = 45°
vo: initial velocity
g: gravitational constant = 9.8m/s^2
x_max: max distance = 180 m
t_max: max time
by replacing the values of the parameters and do vo the subject of the first formula you obtain:
[tex]v_o=\sqrt{\frac{gx_{max}}{sin(2\theta)}}\\\\v_o=\sqrt{\frac{(9.8m/s^2)(180m)}{sin(2(45\°))}}=42\frac{m}{s}[/tex]
with this value of vo you calculate the max time:
[tex]t_{max}=\frac{x_{max}}{v}=\frac{x_{max}}{v_ocos(45\°)}\\\\t_{max}=\frac{180m}{(42m/s)cos(45\°)}=6.06s[/tex]
hence, the initial velocity of the ball is 42m/s and the time in which the ball is in the air is 6.06s
- - - - - - - - - - - - -- - - - - - - - - - - - - -
TRANSLATION:
Para encontrar la velocidad inicial y el tiempo en el que la pelota está volando sobre el suelo, use las siguientes fórmulas:
θ: ángulo = 45 °
vo: velocidad inicial
g: constante gravitacional = 9.8m / s ^ 2
x_max: distancia máxima = 180 m
t_max: tiempo máximo
reemplazando los valores de los parámetros y haciendo el tema de la primera fórmula que obtiene:
con este valor de vo usted calcula el tiempo máximo:
por lo tanto, la velocidad inicial de la pelota es de 42 m / sy el tiempo en que la pelota está en el aire es de 6.06 s
Why do you think sound travels faster in steel than it does in wood? (Hint: Think about the densities of the two materials, and how the particles might be arranged.)
Answer:
If sound waves of the same energy were passed through a block of wood and a block of steel, which is more dense than the wood, the molecules of the steel would vibrate at a slower rate. Sound moves faster through denser air because the molecules are closer together in dense air and sound can be more easily passed on.
Explanation:
A body 'X' of weight 400N placed on the left side of a seesaw 250cm away from the pivot. A body 'Y' of weight 300N is placed on right side of seesaw 3.5m away from pivot. Has the seesaw attained equilibrium?Show your work?
Answer:
No.
Explanation:
if it's in equilibrium then the torque or moment of inertia on both sides should cancel.
Torque is a vector quantity, force times distance.
When doing these, make sure your units are the same by changing centimeters to meters first.
Left side is 400N * (-2.5m) = -1000 Nm
Right side is 300N * (3.5m) = 1050 Nm
-1000 Nm + 1050 Nm does not equal zero so there's a torque on the teeter and it will rotate clockwise. The system is not yet in equilibrium.
An atom of an element can be modeled in several ways. The diagram below shows one model of an atom.
What can be located in the lighter shaded region surrounding the nucleus?
A.
electrons
B.
neutrons
C.
molecules
D.
protons
STUDY ISLAND
Answer:
Electrons
Explanation:
Protons and Neutrons are found within the nucleus and while electrons are much smaller and found outside the nucleus
Answer:
c
Explanation:
please help its in science CER, 30 points
Answer:We have seasons because the earth is tilted (wonky) as it makes its yearly journey around the sun. The Earth's axis is tilted at an angle of 23.5 degrees. This means that the Earth is always "pointing" to one side as it goes around the Sun.
Explanation:
got this from the internet
A simple hydraulic lift is made by fitting a piston attached to a handle into a 3.0-cm diameter cylinder. The cylinder is connected to a larger cylinder with a 24-cm diameter. If a 50-kg woman puts all her weight on the handle of the smaller piston, what weight could the other piston lift?
Answer:
Approximately [tex]3.1 \times 10^4 \; \rm N[/tex] (assuming that the acceleration due to gravity is [tex]g = 9.81\; \rm kg \cdot N^{-1}[/tex].)
Explanation:
Let [tex]A_1[/tex] denote the first piston's contact area with the fluid. Let [tex]A_2[/tex] denote the second piston's contact area with the fluid.
Similarly, let [tex]F_1[/tex] and [tex]F_2[/tex] denote the size of the force on the two pistons. Since the person is placing all her weight on the first piston:
[tex]F_1 = W = m \cdot g = 50\; \rm kg \times 9.81 \; \rm kg \cdot N^{-1} =495\; \rm N[/tex].
Since both pistons fit into cylinders, the two contact surfaces must be circles. Keep in mind that the area of a square is equal to [tex]\pi[/tex] times its radius, squared:
[tex]\displaystyle A_1 = \pi \times \left(\frac{1}{2} \times 3.0\right)^2 = 2.25\, \pi\;\rm cm^{2}[/tex].[tex]\displaystyle A_2 = \pi \times \left(\frac{1}{2} \times 24\right)^2 = 144\, \pi\;\rm cm^{2}[/tex].By Pascal's Law, the pressure on the two pistons should be the same. Pressure is the size of normal force per unit area:
[tex]\displaystyle P = \frac{F}{A}[/tex].
For the pressures on the two pistons to match:
[tex]\displaystyle \frac{F_1}{A_1} = \frac{F_2}{A_2}[/tex].
[tex]F_1[/tex], [tex]A_1[/tex], and [tex]A_2[/tex] have all been found. The question is asking for [tex]F_2[/tex]. Rearrange this equation to obtain:
[tex]\displaystyle F_2 = \frac{F_1}{A_1} \cdot A_2 = F_1 \cdot \frac{A_2}{A_1}[/tex].
Evaluate this expression to obtain the value of [tex]F_2[/tex], which represents the force on the piston with the larger diameter:
[tex]\begin{aligned}F_2 &= F_1 \cdot \frac{A_2}{A_1} \\ &= 495\; \rm N \times \frac{2.25\, \pi\; \rm cm^2}{144\, \pi \; \rm cm^2} \approx 3.1 \times 10^4\; \rm N\end{aligned}[/tex].
A skier starting from rest accelerates in a straight line down a 43,000 m slope at 1 m/s. How fast were they moving after 5 s?
Answer:
5m/s
Explanation:
The skier accelerates at 1 m/s, then, the acceleration is:
[tex]a=1\frac{m}{s^2}[/tex]
to find the speed after 5 seconds you use the following formula:
[tex]a=\frac{v-v_o}{t}[/tex]
but vo = 0m/s because the skier is at rest at the beginning.
You do v the subject of the formula:
[tex]v=at=(1\frac{m}{s^2})(5s)=5\frac{m}{s}[/tex]
hence, the velocity is 5m/s
why is a layer of pollution in the air more visible in winter than summer
Answer:
During winters the planetary boundary layer is thinner as the cooler air near the earth's surface is dense. The cooler air is trapped under the warm air above that forms a kind of atmospheric 'lid'. This phenomenon is called winter inversion
Explanation:
Based on the pattern of reflections shown below, which of the following statements must be true?
A. The mirror is a plane mirror that is tilted at an angle to the vertical.
B. The mirror is a plane mirror that is exactly vertical.
C. The mirror is not a plane mirror.
D. None of the above are definitely true.
Answer:
Explanation:
c
What is the final stage of existence for each type of star?
Answer:
A star like our Sun will become a white dwarf when it has exhausted its nuclear fuel. Near the end of its nuclear burning stage, such a star expels most of its outer material (creating a planetary nebula) until only the hot (T > 100,000 K) core remains, which then settles down to become a young white dwarf.
Can someone give me a detailed explanation on the physics of drums? How do drums get that sound from a physics perspective? (It is for a project on the physics of musical instrument and I have drums
Hi!
Explanation:
A set of wires (called snares) is stretched across a drum head at the bottom of the drum. The vibration of the bottom drum head against the snares produces the drum's characteristic "cracking" tone. Claps, snares, and other "sharp" or "bright" sounds are often used in similar ways in drum patterns.
The skin of the drum vibrates and makes the confetti dance. As the air molecules vibrate against each other, sound waves are formed and the sound of the drums can be heard. Fran explains that the pitch of a drum depends on how tight its skin is. ... Hit a drum hard and this makes big vibrations and a loud sound.
A car of 900 kg mass is moving at the velocity of 60 km/hr. It is brought into rest at 50 meter distance by applying a brake. Now, calculate the force required to stop the car.
Answer: [tex]-2502N[/tex]
Explanation:
[tex](V_2)^2=(V_1)^2+2ad[/tex]
where;
[tex]V_2[/tex] = final velocity = 0
[tex]V_1[/tex] = initial velocity = 60 km/h = 16.67 m/s
[tex]a[/tex] = acceleration
[tex]d[/tex] = distance
First all of, because acceleration is given in m/s and not km/h, you need to convert 60km/h to m/s. Our conversion factors here are 1km = 1000m and 1h = 3600s
[tex]60km/h(\frac{1000m}{1km} )(\frac{1h}{3600s} )=16.67m/s[/tex]
Solve for a;
[tex](V_2)^2=(V_1)^2+2ad[/tex]
Begin by subtracting [tex](V_1)^2[/tex]
[tex](V_2)^2-(V_1)^2=2ad[/tex]
Divide by 2d
[tex]\frac{(V_2)^2-(V_1)^2}{2d} =a[/tex]
Now plug in your values:
[tex]a=\frac{(0)^2-(16.67 m/s)^2}{2(50m)}[/tex]
[tex]a=\frac{0-277.89m^2/s^2}{100m}[/tex]
[tex]a=-2.78m/s[/tex]
If you're wondering why I calculated acceleration first is because in order to find force, we need 2 things: mass and acceleration.
[tex]F=ma[/tex]
m = mass = 900kg
a = acceleration = -2.78m/s
[tex]F=(900kg)(-2.78m/s)\\F=-2502N[/tex]
It's negative because the force has to be applied in the opposite direction that the car is moving.
7. Explain how changes in temperature affect the particle motion of a substance. (3 points)
Answer:
When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of theparticles determines the state of matter of thesubstance. The end result of increased molecular motion is that the object expands and takes up more space.