Answer:
The shorter train has a length of 600m
Explanation:
The equation of motion of the first train can be written as:
[tex]x'=v't[/tex] (1)
v' = 108km/h = 30m/s
Furthermore, you can write the equation of motion of the second train as:
[tex]x=(200+l)+vt[/tex] = xo + vt (2)
v = 36km/h = 10m/s
where you have taken the initial position as measured from the front of the first train to the front of the second one. l is the length of the second train and 200 the separation of it respect to the first train.
For t = 40 both trains have the same position, that is, x=x'. Then, you equal equations (1) and (2), replace t=40, and solve the equation for l:
[tex]x'=x\\\\v't=200+l+vt\\\\(30m/s)(40s)=200+l+(10m/s)(40s)\\\\l=600m[/tex]
Hence, the first train has a length of 600 m
The train behind, or the second train, has twice the length of the first train:
[tex]l'=2l=2(600m)=1200m[/tex]
The shorter train has a length of 600m
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.
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
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:
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.
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
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
How are clouds made. plz halp
Answer:
A cloud is made up of liquid water droplets. A cloud forms when air is heated by the sun. As it rises, it slowly cools it reaches the saturation point and water condenses, forming a cloud. As long as the cloud and the air that its made of is warmer than the outside air around it, it floats!
Explanation:
A cloud is made up op liquid and water droplets.
Answer:
How are clouds made
Explanation:
When sunlight hits water it evaporates into the air and makes water droplets that we see as white fluufly clouds
Johann squeezes a bagel too hard at the supermarket, and it does not return to its original shape when he removes his hand. The bagel has been __________ deformed. What word completes the sentence to show that the bagel has been permanently changed?
Answer:
permanent set
.............
Johann squeezes a bagel too hard that it is not able to return to its original shape. The bagel has Plastic deformation.
What is Plastic Deformation?Plasticity, also referred to as plastic deformation, is the property of a solid material to undergo permanent deformation, a non-reversible change in shape in response to applied forces.
It is a concept used in physics and materials science. For instance, plasticity is demonstrated when a solid piece of metal is bent or pounded into a new shape because the material itself undergoes lasting modifications. Engineering professionals use the term yield to describe the change from elastic to plastic behavior.
Most materials, especially metals, soils, rocks, concrete, and foams, show signs of plastic deformation.
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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
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
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:)
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please help..!
How many photons does it emit in 1 sec. Lamp with a power of 90 W, if it emits monochromatic light with
wavelength 600 nm?
Answer:
idk ha ha ha
Explanation:
Given the word equation below:
sodium + water + sodium hydroxide + hydrogen
What are the reactant(s)?
a
sodium hydroxide and hydrogen
b sodium and water
sodium and sodium hydroxide
d water and hydrogen
Answer:
Sodium and water
Explanation:
We are given with the word equation :
sodium + water + sodium hydroxide + hydrogen
It is required to find that the reactants of the above equation.
In terms of chemical formula we can write it as :
[tex]Na+H_2O\rightarrow NaOH+H_2[/tex]
Reactant of a chemical equation are the elements that are present on its LHS. These are the components of which the equation is composed of. So, the reactants of the given equation are sodium and water.
The reactant are :
-Reactants are Sodium and water.
-Hence, option b is correct.
"Reactants"Word equation :sodium + water + sodium hydroxide + hydrogen
In terms of chemical formula ,we can write it as :
[tex]Na+H_2O\rightarrow NaOH+H_2[/tex
Reactants In a chemical equation, reactants are the elements that are present on its LHS(left hand side).
So, the reactants of the given equation are sodium and water.
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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.
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12. In the last three months mr sharma lost 11\2 kg gained 9\4 kg and then lost 15\4 kg. if he now weigh 95 kg, how much did me sharma weigh to begin with ?
(a)100 kg (b)102kg
(c) 106.5. (d) 104kg
Answer:
(b) 102 kg
Explanation:
95 +15/4- 9/4+11/2 = 102 kg
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.
Answer these please.
Explanation:
hope this helps you
..........
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:
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.
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 :)
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
Is the formular of preasure P=F÷A
Answer:
yes the formula of pressure is P = F/A
Answer:
yes it is
Explanation:
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!
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 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.
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
you walk 5 km east then turned and walked 2km west what would your displacement be
Answer:
3km? im a beginner
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.
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: