A group of students are designing a field study to investigate the length of time a traffic light remains yellow.
Answer:
3 to 7 seconds.
Explanation:
According to the traffic engineers the length or the duration of the signal to turn form yellow or amber to green is more than 5 seconds. A time interval is needed to easy out the traffic flow.5. Can you get the machine with efficiency 100% in practice? Why?
Answer:
No,
Explanation:
Efficiency of a machine is always less than 100% as output energy is always less than the input energy, because some energy is lost to overcome friction.
Una carga q1 = - 45 µC esta colocada a 30 mm a la izquierda de una carga q2 = 25 µC . ¿Cuál es la fuerza resultante sobre una carga de q3 = 20 µC localizada exactamente 50 mm arriba de la carga de 25µC ?
Answer:
La fuerza resultante sobre q₃ es -1.2245 × 10⁻¹⁵ i + -0.24 × 10⁻¹⁵ j
La magnitud de la fuerza resultante sobre q₃ es aproximadamente 1.25 × 10⁻¹⁵ N
Explanation:
q₁ = -45 μC = -45 × 10⁻⁶ C
r₁₂ = 30 mm = 30 × 10⁻³ m
q₂ = 25 μC = 25 × 10⁻⁶ C
r₂₃ = 50 mm = 50 × 10⁻³ m
q₃ = 20 μC = 20 × 10⁻⁶ C
k = 9×10⁻⁹ N·m²/C²
Por lo tanto;
r₁₃ = √(50² + 30²) = 10·√(34)
F₁₂ = 9×10⁻⁹ × (-45 × 10⁻⁶)×(25 × 10⁻⁶)/(30 × 10⁻³)² = -1.125 × 10⁻¹⁴
F₁₂ = -1.125 × 10⁻¹⁴ N
F₂₃ = 9×10⁻⁹ × (20 × 10⁻⁶)×(25 × 10⁻⁶)/(50 × 10⁻³)² = 1.8 × 10⁻¹⁵ j
F₁₃ = 9×10⁻⁹ × (-45 × 10⁻⁶)×(20 × 10⁻⁶)/(10·√34 × 10⁻³)² = -2.38× 10⁻¹⁵
Los componentes de F₁₃ son;
-2,38 × 10⁻¹⁵ × cos (arctan (30/50)) = -2,04 × 10⁻¹⁵ j
-2,38 × 10⁻¹⁵ × sin (arctan (30/50)) = -1,2245 × 10⁻¹⁵ i
La fuerza resultante sobre la carga q₃, [tex]\left | \underset {F_3} \rightarrow \right |[/tex] = [tex]\underset{F_{13}}{\rightarrow}[/tex] + [tex]\underset{F_{23}}{\rightarrow}[/tex]
∴ [tex]\left | \underset {F_3} \rightarrow \right |[/tex] = 1.8 × 10⁻¹⁵ j + -1.2245 × 10⁻¹⁵ i + -2.04 × 10⁻¹⁵ j
La fuerza resultante sobre q₃ es [tex]\left | \underset {F_3} \rightarrow \right |[/tex] = -1.2245 × 10⁻¹⁵ i + -0.24 × 10⁻¹⁵ j
La magnitud de la fuerza resultante sobre q₃,
[tex]\left | F_3 \right |[/tex] = √((-1.2245 × 10⁻¹⁵)² + (-0.24 × 10⁻¹⁵)²) ≈ 1.25 × 10⁻¹⁵
La magnitud de la fuerza resultante sobre q₃, [tex]\left | F_3 \right |[/tex] ≈ 1.25 × 10⁻¹⁵ N.
I let go of a piece of bread from a balcony. A bird flying 5.0 m overhead sees me drop it, and starts to dive straight down towards the bread the instant that I release it. She catches it after it falls 3.0 m. Assuming she accelerates constantly from rest (v0 = 0) at the time I let go of the bread, what is her acceleration? Show your work
This question can be solved using the equations of motion. There are two scenarios where the equations of motion can be used. The first scenario is the free-fall motion of the piece of bread. The second scenario is the uniformly accelerated motion of the bird.
The acceleration of the bird is "a = 26.13 m/s²".
First, we will calculate the time taken by the bread to fall 3 m. Using the second equation of motion for this free-fall motion:
[tex]h = v_it + \frac{1}{2}gt^2[/tex]
where,
h = height fall = 3 m
vi = initial velocity = 0 m/s
g = acceleration due to gravity = 9.8 m/s²
t = time taken = ?
Therefore,
[tex]3\ m = (0\ m/s)t+\frac{1}{2}(9.8\ m/s^2)t^2\\t = \sqrt{\frac{(3\ m)(2)}{9.8\ m/s^2}}\\\\t = 0.78\ s[/tex]
The bird took the same time to catch the bread. Now applying the second equation of motion to the bird's motion:
[tex]s = v_it + \frac{1}{2}at^2[/tex]
where,
s = distance covered by the bird = 5 m + 3 m = 8 m
vi = initial velocity of the bird = 0 m/s
a = acceleration of the bird = ?
t = time taken = 0.78 s
Therefore, using these values we get:
[tex]8\ m = (0\ m/s)(0.78\ s)+\frac{1}{2}a(0.78\ s)^2\\\\a = \frac{16\ m}{(0.78\ s)^2}[/tex]
a = 26.13 m/s²
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i. The lift raises a car to a height of 1.8 m using a force of 5500 N. How much work does the lift
perform? (1 point)
Work = force x distance
Work = 5500 x 1.8
Work = 9900 N
The work measure of energy transfer that occurs when an object is moved over a distance by an external force at least part of which is applied in the direction of the displacement.
Work = force x distance
Work = 5500 x 1.8
Work = 9900 N
therefore, work does 9900 N
What is work?Work is force applied over distance. Examples of work include lifting an object against the Earth's gravitation, driving a car up a hill, and pulling down a captive helium balloon. Work is a mechanical manifestation of energy. The standard unit of work is the joule (J), equivalent to a newton - meter (N · m).
What is work and energy?Work is defined as transferring energy into an object so that there is some displacement. Energy is defined as the ability to do work. Work done is always the same. Energy can be of different types such as kinetic and potential energy.
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The refractive index of water is 1.33
and that of diamond is 2.42. Draw a labelled diagram to show how a light ray bends when it travels from water
into diamond.
Explanation:
light travel slower in daimond
hai điện tích q1 =-2.10^(-8), q2=1,8.10^(-8) đặt tại A và B trong không khí,AB=8cm. Một điện tích q3 đặt tại C. 1, C ở đâu để q3 cân bằng
Answer:
Đáp án là vị trí để đặt q3 tại vị trí cân bằng là cách A một đoạn 0,0411 m
và nằm trong AB
Explanation:
Do q1 và q2 trái dấu nên q3 nằm trong
gọi r1 là vị trí từ A đến q3 suy ra r2=0.08-r1
Vị trí cân bằng nên [tex]\frac{q1}{r1^{2} }[/tex] = [tex]\frac{q2}{(0.08-r1)^{2} }[/tex]
what are the factors of evaporation and give explanation
Answer:
The three primaryfactors of evaporation are heat, atmospheric pressure (which determines the percentage of moisture) and the movementofair. At the molecular level, there is no strict boundary between the liquid state and the vapor state
calculate the potential energy stored in a meta ball of mass of 80 kg kept at a height of 15m from the earth surface . What will be the potential energy when the metal ball is kept on the earth surface Take (g- 9.8 m/s]
Answer:
11760 J
Explanation:
cuz potential engery is PE = MHG
SO 80×15×9.8= 11760 J
Answer:
11769j
Explanation:
here,
mass(m)=80 kg
height(h)=15m
acceleration due to gravity(g)=9.8m/s^2
now,
potential energy = m×g×h
= 80×9.8×15
= 11760j
Which word describes the maximum a point moves from its rest position when a wave passes?
Answer:
Amplitude.
Explanation:
A wave can be defined as a disturbance in a medium that progressively transports energy from a source location to another location without the transportation of matter.
In Science, there are two (2) types of wave and these include;
I. Electromagnetic waves: it doesn't require a medium for its propagation and as such can travel through an empty space or vacuum. An example of an electromagnetic wave is light.
II. Mechanical waves: it requires a medium for its propagation and as such can't travel through an empty space or vacuum. An example of a mechanical wave is sound.
An amplitude can be defined as a waveform that's measured from the center line (its origin or equilibrium position) to the bottom of a trough or top of a crest.
Hence, an amplitude is a word that describes the maximum displacement a point moves from its rest position when a wave passes.
On a graph, the vertical axis (y-axis) is the amplitude of a waveform and this simply means that, it's measured vertically.
Mathematically, the amplitude of a wave is given by the formula;
x = Asin(ωt + ϕ)
Where;
x is displacement of the wave measured in meters.
A is the amplitude.
ω is the angular frequency measured in rad/s.
t is the time period measured in seconds.
ϕ is the phase angle.
Which type of reactions usually happens slowest?
Answer:
option b is correct..................
The air pressure at the base of the mountain is 75.0cmof mercury while at the top is 60 cm of mercury given that the average density of air is 1.25kg/m³ and the density of mercury is13600kg/m³and g=10N/kg. calculate the height of the mountain?
Answer:
이 질문입니까?
Explanation:
평균 공기 밀도가 1.25kg/m³이고 수은 밀도가 13600kg/m³이고 g=10N/kg인 경우 산 기슭의 기압은 수은의 75.0cm이고 정상의 수은은 60cm입니다. 산의 높이를 계산?
The air pressure at the base of the mountain is 75.0 cm of mercury while at the top is 60 cm of mercury. The height of the mountain is approximately 0.1468 meters.
The pressure difference (∆P) between the base and the top of the mountain is given by:
∆P = ρgh
Where:
ρ is the density of the fluid (mercury) = 13,600 kg/m³
g is the acceleration due to gravity = 10 N/kg
h is the height of the fluid column (mountain)
We have the pressure difference: ∆P = 75.0 - 60.0 = 15.0 cmHg.
To convert cmHg to pascals (Pa), we use the conversion factor: 1 cmHg = 1333.22 Pa.
∆P = 15.0 × 1333.22
∆P = 19,998.3 Pa
h = ∆P ÷ (ρg)
h = 19,998.3 ÷ (13,600 × 10)
h = 0.1468 m
Therefore, the height of the mountain is approximately 0.1468 meters.
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Explain why some of the tree get detached from a tree if we vigorously shake it's Branch.
Answer:
When a tree is vigorously shaken, the branches of the tree come in motion but the leaves tend to continue in their state of rest due to inertia of rest. As a result of this, leaves get separated from the branches of the tree and hence fall down.
Answer:
When a tree is vigorously shaken, the branches of the tree come in motion moving left and right and shake the leaves off, that's why some of the tree got detached when we vigorously shake its branch.
Explanation:
Like I did in the answer section.
Resistivity of metallic wire
depends on *
It's length
It's shape
It's thickness
Nature of material
Answer:
nature of the material
hope this help you
Two forces have magnitudes in the ratio
3 : 5 and the angle between their directions is 60°. If their resultant is 35 N,
what are their magnitudes ?
Answer:
F1=26N and F2=09N ..this is from the two simultaneously equations
ASAP!! Please help me out here
Answer:
Option: DExplanation:
As,
In Option,
A:
There are two same positive ions so they will move away from each other.
B:
There is one negative and positive ion so they will move towards each other.
C:
Again there is one negative and positive ion so they will move towards each other.
D:
Here, there is neutral ions so they will not move and its the correct option.
state the advantages and disadvantages of alkaline battery over a lead acid accumulator
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
What is alkaline battery ?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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A 0.0780 kg lemming runs off a
5.36 m high cliff at 4.84 m/s. What
is its potential energy (PE) when it
jumps?
Answer:
4.097 Joules
Explanation:
Applying,
P.E = mgh............... Equation 1
Where P.E = Potential energy, m = lemming mass, h = height, g = acceleration due to gravity
From the question,
Given: m = 0.0780 kg, h = 5.36 m
Constant: g = 9.8 m/s²
Substitute these values into equation 1
P.E = 0.0780(9.8)(5.36)
P.E = 4.097 Joules.
Hence the potential energy is 4.097 Joules
Answer:
4.097 J
Explanation:
The plane of a5cm*8cm rectangular loop of wire is parallel to a 0.19T magnetic field the loop carries a current of 6.2 A. What torque acts on aloop? What is the magnetic moment of the loop?
Answer:
Torque; τ = 4.712 × 10^(-3) J
Magnetic moment; M = 0.0248 J/T
Explanation:
Torque is gotten from the formula;
τ = BIA
Where;
B is magnetic field
I is current
A is area
We are given;
B = 0.19T
I = 6.2A
Rectangle dimensions = 5cm by 8cm = 0.05m by 0.08m
Thus;
Area; A = 0.05m × 0.08m = 0.004 m²
Thus;
τ = 0.19 × 6.2 × 0.004
τ = 4.712 × 10^(-3) J
Formula for the magnetic moment is given by;
M = IA
M = 6.2 × 0.004
M = 0.0248 J/T
HELP‼️‼️ A car horn creates a 595 Hz tone at rest. Two cars pass on the street, each going 20.0 m/s; the first car honks. What frequency does the other car hear before they pass each other?
The frequency of the other car is 669HZ
Let start off by writing out the parameters given in the question
frequency= 595 HZ
Speed of sound(v)= 343m/s
Speed of the car(vs)= 20m/s
Speed of the second car(vo) = 20m/s
The frequency of the other car can be calculated as follows
(v+vo/v-vs) f
= (343+20/343-20)595
= (363/323)595
= 1.1238(595)
= 669 HZ
Hence the frequency of the other car is 669 HZ
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You toss an apple across the room to a friend. Which of the following statements is true about the apple at the top of its trajectory?
A. Its acceleration is zero.
B. The horizontal component of its velocity is zero.
C. The vertical component of its velocity is 9.8 m/s down.
D. Its acceleration is 9.8 m/s2 down.
(A) A triangular glass prism of thickness 12cm is placed on a mark on a piece of paper resting on a horizontal bench. If the refractive index of the material of the prism is 1.5, calculate the apparent displacement of the mark.
(B)Water is poured into a jar to a depth of 24cm. The bottom of the jar appears
to be raised by 6cm when viewed vertically. Calculate the refractive index of water.
Part A - The apparent displacement of the mark is 4 cm.
The refractive index of a material, n = real depth, D/apparent depth, L.
So, n = D/L
Since the refractive index of the triangular glass prism is 1.5, n = 1.5. Also, the triangular glass prism is 12 cm thick and placed on a mark on a piece of paper resting on a horizontal bench. So, the real depth of the mark on the piece of paper through the triangular prism is D = 12 cm and its apparent depth is L.
Since n = D/L,
making L, subject of the formula, we have
L = D/n
Substituting the values of the variables into the equation, we have
L = D/n
L = 12 cm/1.5
L = 8 cm
so, the apparent depth of the mark is 8 cm.
So, the apparent displacement of the mark is d = D - L = 12 cm - 8 cm = 4 cm
Thus the apparent displacement of the mark is 4 cm.
Part B - The refractive index of water, n = 1.33.
The refractive index of a material, n = real depth, D/apparent depth, L.
So, n = D/L
Since the depth of water in the jar is 24 cm, the real depth, D = 24 cm.
Also, the bottom of the jar appears to be raised by 6 cm. So, the apparent depth, L = 24 cm - 6 cm = 18 cm
Since n = D/L, the refractive index of water n = D/L
Substituting the values of the variables into the equation, we have
n = D/L
= 24 cm/18 cm
= 1.33
So, the refractive index of water, n = 1.33.
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: 1 khối khi lý tưởng nhận được nhiệt lượng 200J, khi đó khí nở ra đẩy pittong bằng 1 công 80J.
Vậy nội năng Của khí là bao nhiêu
Answer:
DU = 120 Joules
Explanation:
Given the following data;
Quantity of energy = 200 J
Work = 80 J
To find the change in internal energy;
Mathematically, the change in internal energy of a system is given by the formula;
DU = Q - W
Where;
DU is the change in internal energy.
Q is the quantity of energy.
W is the work done.
Substituting into the formula, we have;
DU = 200 - 80
DU = 120 Joules
There is given an ideal capacitor with two plates at a distance of 3 mm. The capacitor is connected to a voltage source with 12 V until it is loaded completely. Then the capacitor is disconnected from the voltage source. After this the two plates of the capacitor are driven apart until their distance is 5 mm. Now a positive test charge of 1 nC is brought from the positively charged plate to the negatively charges plate. How large is the kinetic energy of the test charge? The test charge of 1 nC can be regarded to be so small that it does not influence the electric field between the two plates of the capacitor.
The kinematic energy of the positive charge is 2 10⁻⁸ J
This electrostatics exercise must be done in parts, the first part: let's start by finding the charge of the capacitor, the capacitance is defined by
C = [tex]\frac{Q}{\Delta V}[/tex]
C = ε₀ [tex]\frac{A}{d}[/tex]
we solve for the charge (Q)
[tex]\frac{Q}{\Delta V} = \epsilon_o \frac{A}{d}[/tex]
indicates that for the initial point d₁ = 3 mm = 0.003 m and the voltage is DV₁ = 12
Q = [tex]\epsilon_o \ \frac{A \ \Delta V_1 }{d_1}[/tex]
Now the voltage source is disconnected so the charge remains constant across the ideal capacitor.
For the second part, the condenser is separated at d₂ = 5mm = 0.005 m
Q = \epsilon_o \ \frac{A \ \Delta V_2 }{d_2}
we match the expressions of the charge and look for the voltage
[tex]\frac{\Delta V_1}{d_1} = \frac{\Delta V_2}{d_2}[/tex]
ΔV₂ = [tex]\frac{d_2}{d_1 } \ \Delta V_1[/tex]
The third part we use the concepts of conservation of energy
starting point. With the test load (q = 1 nC = 1 10⁻⁹ C) next to the left plate
Em₀ = U = q DV₂
Em₀ = q \frac{d_2}{d_1 } \ \Delta V_1
final point. Proof load on the right plate
Em_f = K
energy is conserved
Em₀ = em_f
q \frac{d_2}{d_1 } \ \Delta V_1 = K
we calculate
K = 1 10⁻⁹ 12 [tex]\frac{0.005}{0.003}[/tex]
K = 20 10⁻⁹ J
In this exercise, as the conditions at two different points of separation give, the area of the condenser is not necessary and with conservation of energy we find the final kinetic energy of 2 10⁻⁸ J
Is velocity ratio of a machine affected by applying oil on it? Explain with reasons.
Answer:
when it comes to machines being Rusty oil is like the root loosener
como previene un diafragma el embarazo
Answer:
Un diafragma es una pieza de silicona o de goma reutilizable que cubre el cuello del útero. El diafragma se coloca dentro de la vagina con espermicida antes de tener relaciones sexuales para prevenir un embarazo. El diafragma es un dispositivo anticonceptivo que impide que los espermatozoides ingresen en el útero.
What type of sound do the thinner
strings on a guitar make?
A. Higher pitched sounds
B. Lower pitched sounds
C. Loud sounds
D. Quiet sounds
Answer:
d
Explanation:
I'm not perfectly sure so check again
Using your Periodic Table, which element below has the smallest atomic radius? A.) Sodium, B.) Chlorine, C.) Phosphorus, D.) Iron
Chlorine has the smallest atomic radius since the atomic radius decreases as you travel to the right and up
why is it important to have regular super vision of the weights and the measurements in the market?
Answer:
Obeying to weights & measurement regulations in both national and international metrology legislation, standards and test procedures is a requirement to participate in any market because it's aimed to safeguard the consumers and promote fair competition, which provides efficiency and saves unnecessary costs to U.S. businesses and stakeholders.
Explanation:
In the U.S., the National Institute of Standards and Technology (NIST) has an Office of Weights and Measures (OWM) that represents the country in the International Organization of Legal Metrology (OIML)
what is the definition of unit?definition of unit?
Answer:
The Reference standard with which we carry out the measurement of any physical quantity of the same kind is know as unit .
I HOPE I HELP YOU.
Answer:
The standard quantity which is used for the comparison with an unknown quantity is called unit.
Unit is a known or standard quantity in terms of which other physical quantities are measured.
for examples;kilogram,metre,second,etc.
Explanation:
hope it helps you
