Can someone help me please this test is very important

Answer:

Resistance is defined as the property of a conductor to resist the flow of charges through it. The resistance of conductor is numerically given as the ratio of potential difference across its length to the current flowing through it.

Explanation:

Answer:

The resistance of a thin wire is greater than the resistance of a thick wire because a thin wire has fewer electrons to carry the current. The relationship between resistance and the area of the cross section of a wire is inversely proportional .

The best way to think about this is:

A thick/wide road, with many lanes, can carry more cars than a thin/narrow road, with only one or two lanes.

1. The average speed of Luis over the 60 s is 1.33 m/s

2. The average velocity of Luis over the 60 s is zero.  

1. The average speed can be calculated with the following equation:

[tex] S = \frac{d}{t} [/tex]

Where:

d: is the total distance traveled

t: is the total time = 60 s

The total distance can be calculated by the sum of the distance traveled to the truck (40 m) and the distance traveled to his home (the same 40 m), as follows:

[tex] d = 40 m + 40 m = 80 m [/tex]

So, the average speed is:

[tex] S = \frac{d}{t} = \frac{80 m}{60 s} = 1.33 m/s [/tex]

Hence, Luis's average speed over the 60 s is 1.33 m/s.

2. Now, the average velocity is a vector given by:

[tex]v = \frac{\Delta x}{\Delta t} = \frac{x_{f} - x_{i}}{t}[/tex]

Where:

[tex]x_{f}[/tex]: is the final distance traveled (the way to his home) = 40 m

[tex]x_{i}[/tex]: is the initial distance traveled (the way to his truck) = 40 m

Δt: is the total time = t = 60 s

Given that Luis in his journey, returns to the same starting point (his house), the total displacement is zero, and so the average velocity is also zero:                              

[tex]v = \frac{x_{f} - x_{i}}{t} = \frac{40 m - 40 m}{60 s} = 0[/tex]

Therefore, Luis's average velocity over the 60 s is zero.  

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As shown in the figure below, Luis rushes 40 m toward his truck. He notices he forgot his shoes and returns back to his house. His total travel time is 60 s.

Answer:

What is Luis’s average velocity over the 60 s period?

Answer: 0 m/s

What is Luis’s average speed over the 60 s period?

Answer: 1.33  m/s

Answer:

nước sôi: 440/17 l

nước 15°C:1260/17 l

Answer:

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

Explanation:

Answer:

But negative acceleration means that the rate of change of velocity is negative or velocity decreases. Example: (1) When we apply brakes in a moving car, then negative acceleration acts on it and the car stops. (2) When we throw a ball upwards, then also negative acceleration acts on it.

Explanation:

If it helps you mark me as a brainleast

MATHEMATICALLY A NEGATIVE ACCELERATION MEANS YOU WILL SUBTRACT FROM THE CURRENT VALUE OF THE VELOCITY.

Answer with Explanation:

Let me answer this in a simple way, since the density of stone is greater than that of water, the stone sinks as the weight of the stone is greater than the weight of water displaced by it. But the ship is designed in such a way that the relative density of the ship always becomes less than that of water. Therefore, the weight of the water displaced becomes equal to the total weight of the ship and thus it floats.

There are many other ways to explain this but this should give you the general idea.

[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:

96 meters

Explanation:

d = st

d = (8 m/s)(12 s)

d = 96 m

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

Hope this helps!!! :)

Answer:

hi

Explanation:

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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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Answer:

3.8 x 10^-5

Explanation:

all you doing is putting it in the standard form I hope this help

Answer:

0.25p.a

Explanation:

force=15N area=60m²

so pressure =force/area =15N/60m²=0.25p.a

Answer:

difference between mass and weight is that mass is amount of matter in a material while weight is a measure of how the force of gravity acts upon that mass.the mass of an object will be same on earth and mars but its weight on both planets will be different.

Option ( iv ) is the correct answer.

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

Explanation:

p = F /A

F = P×A

F = 30,000 Pa / 0.1 m²

F = 300,000 N

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:

There is no pressure of your feet on the scales, and no pressure of the floor on the scales, so the scales will read zero*. Hence, your weight, in a freely falling lift is zero

We know

[tex]\boxed{\sf Spring\:constant(K)=\dfrac{F}{x}}[/tex]

[tex]\\ \sf\longmapsto K=\dfrac{1}{0.5}[/tex]

[tex]\\ \sf\longmapsto K=2N/m[/tex]

Explanation:

string roller is called an example of wheel and axel because The thin rod which needs to be turned is called the axle and the wider object fixed to the axle, on which we apply force is called the wheel.

hence the we apply force on the roller and the string gets tight.

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:

False.

Explanation:

A warm up is stretching in the beginning.

Answer:

Wait until the end of the semester to complete all work.

Explanation:

this is the obvious answer.

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Answer:

Wait until the end of the semester to complete all work

Answer:

Alkaline batteries have longer shelf life than other batteries of the chloride type electrolyte batteries. They have a much higher energy density compared with other batteries. This allows the battery to produce the same energy while lasting longer than other batteries.

Advantage

1) Alkaline battery lasts long than other batteries  

2) It have a  much higher energy density

Disadvantage :

1) They are heavier and bulkier

2) They have high internal resistance

An alkaline battery is a type of primary battery that derives its energy from the reaction between zinc metal and manganese dioxide.

Advantage

Alkaline battery   can produce same amount of energy by lasting longer than other batteries  as it have longer shelf life than  lead acid accumulator​

Alkaline battery  have a much higher energy density compared to lead acid accumulator

Disadvantage :

Alkaline battery  are heavier and bulkier

Alkaline battery   have high internal resistance

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Answer:

Pascal is a derived unit because it cannot be expressed in any physics terms, but it is an expression of fundamental quantities.

Explanation:

[tex]{ \sf{Pasacal \: ( Pa) = \frac{newtons}{metres {}^{2} } }} \\ \\ { \sf{Pasacal \: (Pa) = \frac{kg \times {ms}^{ - 2} }{ {m}^{2} } }}[/tex]

Answer:

the process of comparing unknown quantities with known standards quantities are known as measurement