Look at the distance-time graph below. It shows Angela's journey as she walks to the end of the road and back. The end of the road is 40 m away. After how many seconds did she arrive back where she started?

Option ( iv ) is the correct answer.

A vector quantity the physical quantity that has both direction as well as magnitude.

my views

Explanation:

Figure (8) shows a rod made up of copper and wood joined together. The rod is heated at the joint in the centre for about a minute. At which point – A, B, C or D, would it show the lowest temperature? PLEASE GIVE REASONS ALSO(MINIMUM 2)

Answer:

Furthermore, the Pythagorean theorem works when the two added vectors are at right angles to one another - such as for adding a north vector and an east vector.

Answer:

True

Explanation:

The bigger an object is, the more force you must apply to move the object. Think about it like moving a mouse compared to moving an elephant. You can't move the elephant by yourself, because you don't have enough strength or force to move it. But, you can easily pick up a mouse, because it requires less force, or strength. Hope this helped :)

Answer:

I don't know

Explanation:

sorry but I will help u next time kk

Doppler frequency, the other car hear before they pass each other is 668.68 Hz.

Frequency is the number of occurrences of a repeating event per unit of time.

The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source.

According to the Doppler Effect, the frequency observed is

  [tex]fo=fs\frac{v+v_{o} }{v-v_{s} }[/tex]

[tex]f_{o}=595\frac{343+20 }{343-20 }\\f_{o} = 668.68 Hz[/tex]

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Radiation is energy that comes from a source and travels through space at the speed of light. This energy has an electric field and a magnetic field associated with it, and has wave-like properties. You could also call radiation “electromagnetic waves”.

cdc

Answer:

Explanation:

A plane mirror is the kind you look into when you look into a "regular" mirror. The image you see is right-side-up. These images are virtual. Real images are always upside down and are made by mirrors that are "parabolic" in shape. Virtual images are always right-side-up.

The magnitude (size or numerical value) and the direction.

Hope this helps!!! :)

Answer:

25 mm = 0 deg C

200 mm = 100 deg C

200 - 25 = 175 = change in thread per 100 deg C

95 - 25 = 70 mm - change in thread from 0 deg C

70 / 175 * 100 = 40 deg C    final temperature at 95 mm

Answer:

Elements in the same group have the same number of valence electrons.

When moving right across a period, the valence electrons of the main group elements increase by one.

When moving down a group, the valence electrons of the main group elements increase by one.

Elements in the same period have the same number of valence electrons.

Elements in the same period of the periodic table have valence electrons in the same energy levels.

When elements are in the same period on the periodic table, it means that they have the same number of shells.

The energy level of valence electrons in a atom depends on how far it is from the nucleus. This means that:

For instance, Boron, Carbon and Nitrogen will have valence electrons in the same energy levels.

In conclusion, elements in the same period will have valence electrons in the same energy levels.

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Answer:

Decrease

Explanation:

The pressure is the force per unit area. So, P=F/A

Thus the pressure P is inversely proportional to contact area A.

So when area increases , the pressure will be decreasing.

AnswerIt is continuously falling towards the surface of the earth

Explanation:

since gravity from earth is the thing that keeps it constantly in orbit

[tex]\boxed{\sf W=Fscos\Theta}[/tex]

[tex]\\ \sf\longmapsto W=150(50)cos 60[/tex]

[tex]\\ \sf\longmapsto W=7500\times \dfrac{1}{2}[/tex]

[tex]\\ \sf\longmapsto W=3750J[/tex]

Answer:

cần cung cấp 70 độ vì nước sôi ở 100°C

Explanation:

Answer:

12000gram

Explanation:

1kg=1000gram

so, 12kg=12x1000

12kg=12000gram

Given amount=12kg

[tex]\boxed{\sf 1kg=1000g}[/tex]

[tex]\\ \sf\longmapsto 12kg=12(1000)[/tex]

[tex]\\ \sf\longmapsto 12kg=12000g[/tex]

Answer:

lemon

Explanation:

the lower the number the hier hydrogen ions

Answer: B

Explanation:

Answer:

HOPE IT HELP YOU A LOT :)

I prove it also .

Answer:

Newtons Second law of motion states that"The rate of change of momentum is directly proportional to the force applied"

Answer:

Snth = u + a/2 ( 2n - 1)

Explanation:

Do you need explanation based on graph, integration or other method?

Answer:

a). Silver, Ag

b). Iron, Fe

c). Copper, Cu

d). Aluminium, Al

e). Gold, Au

Answer:

gsbddgshdhsghhdhdhvvs

Longitudinal waves

Transverse waves

Electromagnetic Waves

Water waves

Rope waves

LIght Waves

Answer:

Explanation:

We first need to convert the 40 km/h to m/s. Going by the fact that 40 has only 1 significant figure in it, 40 km/h = 10 m/s. The rest of the values are in their proper labels. We will use the equation:

[tex]v^2=v_0^2+2a[/tex]Δx where the final velocity is 0 because the car is coming to a stop at the end; the initial velocity is 10 m/s, the acceleration (or, rather, deceleration) is -.5 m/s/s, and our unknown which is displacement. Filling in:

[tex]0=(10)^2+2(-.5)[/tex]Δx and solving for Δx:

Δx = [tex]\frac{-100}{2(-.5)}[/tex] which ends up being simply that

Δx = 100 m

Answer:

Explanation:

By being close to an atom that will gladly take the electrons being offered.

Suppose you are talking about Be. It is in the second column. It has two outer electrons that can be given away. It will not give away one of the two remaining electrons because they are too close to the + nucleus.

Along comes a Fluorine atom. It has 7 electrons in its outer ring. The chemistry of the situation allows it to take on one of the two electrons Be is offering. It is all a matter of charges and attractions.

Another Fluorine atom will take on the remaining electron from the Be. The outer ring cannot take on more than 1 electron, but that is enough

Answer:

any person who opens the door he applies pulling force

Answer:

The net force is 91780.8 N.

Explanation:

mass, m = 8950 kg

Radius, R = 9.33 miles = 15015.2 m

Time, T = 0.123 h = 442.8 s

There are two forces acting on the plane.

Horizontal force is the centripetal force and the vertical force is the weight.

[tex]Fx =m R w^2\\\\Fx = m R \frac{4\pi^2}{T^2}\\\\Fx = 8950\times 15015.2\times \frac{4\times 3.14\times 3.14}{442.8\times 442.8}\\\\Fx = 27030.8 N \\\\Fy = m g \\\\ Fy = 8950\times 9.8 \\\\Fy = 87710 N[/tex]

The net force is

[tex]F = \sqrt{Fx^2 + Fy^2}\\\\F = \sqrt {27030.8^2 + 87710^2}\\\\F = 91780.8 N[/tex]

7351.35Hz

f0= v-Vo/v-Vs × FSA

= 340-0 /340+30 ×8000

= 340/370× 8000

= 7351.35hz

Answer:

2.5 m

Explanation:

Potential energy is the energy stored in an object as a result of its position relative to other objects

The change in potential energy is given by:

ΔPE = mgh;

where ΔPE is the change in potential energy, m is the mass if the object, g is the acceleration due to gravity and h is the change in height of the object.

Hence given that g = 10 m/s², ΔPE = 150 J, m = 6 kg, hence:

ΔPE = mgh

150 = 6 * 10 * h

150 = 60h

h = 2.5 m

Hence the change in height is 2.5 m

Answer:

Explanation:

The first part of this question is simply asking us to convert the speed from miles per hour to meters per second:

[tex]60.0\frac{mi}{hr}*\frac{1hr}{3600sec}*\frac{1609.34m}{1mi}=26.8\frac{m}{s}[/tex] choice C.

The next part wants us to use the equation for acceleration and find the acceleration:

[tex]a=\frac{v-v_0}{t}[/tex] where v is final velocity, v0 is initial velocity, and t is time in seconds (which was one of the reasons we had to convert the initial velocity from 60.0 mph to m/s):

[tex]a=\frac{26.8-0}{2.5}[/tex] and

a = 10.7 m/s/s, choice B.

Answer:

Density is directly proportional to pressure

Explanation:

As pressure increases (with constant temperature), density also increases.

Density is inversely proportional to temperature.

The hydro power plant consists of a (artificial) dam that builds gravitational potential energy, P.E. from natural flowing water sources, by locating the dam along the water path. The stored potential energy, P. is converted into kinetic energy, K.E. as the water falls from the dam, down to the turbines, located at a much lower level according to the following principle of conservation of energy equation;

Total Mechanical Energy, M.E. = The potential energy of the water, P.E. + The kinetic energy of the water, K.E. = Constant

M.E. = P.E. + K.E. = Constant

Where;

P.E. = m·g·h

K.E. = (1/2)·m·v²

m = Mass

g = The acceleration due to gravity

h = The height of the dam

v = The velocity

The charts can be explained as follows;

Given that the potential energy P.E. = m·g·h, we have that the potential energy is directly proportional to the height of the dam, and therefore, at mid height, the potential energy would be half the maximum value, and we have;

At mid height, P.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex]

At the top of the dam, the (vertical) velocity of the water = 0, therefore, the kinetic energy = 0

Therefore, at the top of the dam, we get;

M.E. = [tex]P.E._{max}[/tex] + 0 =

M.E. = [tex]\mathbf{P.E._{max}}[/tex]

Similarly, at the bottom of the dam, the height, h = 0, therefore, being proportional to the height, P.E. = 0, and the velocity is maximum, and at the bottom, we have;

M.E. = 0 + [tex]K.E._{max}[/tex]

The first chart, water is halfway down the dam

At the halfway down therefore, we have;

P.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex]

M.E. = [tex]P.E._{max}[/tex] = (1/2)·

∴ K.E. = [tex]P.E._{max}[/tex] - (1/2)·

Therefore the first chart, water is halfway down the dam;

Halfway, K.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex] = P.E.

∴ K.E. = P.E.  as shown on the chart

The second chart, water has reached the turbine

Water reaches the turbine at the bottom, and as explained above, we get;

M.E. = 0 + [tex]K.E._{max}[/tex]

∴ M.E.≈ [tex]K.E._{max}[/tex]

Therefore, when water has reached the turbine at the bottom of the dam, the kinetic energy is approximately proportional to the total mechanical energy as shown in the chart

The third chart, water is at the top of the dam

Here as shown above, we have;

The total mechanical energy, M.E. ≈ [tex]\mathbf{P.E._{max}}[/tex] as shown on the chart

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