Answer: ?
Explanation:
You've always wondered about the acceleration of the elevators in the 101 story high Empire State Building. One day, while visiting New York, you take your bathroom scale into the elevator and stand on it. The scale reads 177 lb as the door closes. As the elevator moves upward the scale reading varies between a minimum value of 138 lb and a maximum value of 227 lb as the elevator travels 101 floors.
a. What is the magnitude of the acceleration as the elevator starts upward?
b. What is the magnitude of the acceleration as the elevator brakes to a stop?
Answer:
a) 2.8 m/s2
b) 2.2 m/s2
Explanation:
The lecture on the bathroom scale is equal to the normal force that the scale exerts on you, and is directed upward.There is another force acting on you, which is gravity.This force (which we call weight) is the product of the mass times the acceleration due to gravity, g, and is directed downward, opposite to the normal force.When the elevator is at rest, no acceleration takes place, so according Newton's 2nd Law, no net force must be exerted on you.In this condition, the normal force Fn₀ must be equal to the weight:[tex]F_{no} = m * g = 177 lb (1)[/tex]Since the normal force takes any value needed to satisfy Newton's 2nd law, the two extreme lectures can be expressed as follows, in terms of the two forces acting on you while the elevator is moving upward:[tex]F_{n1} = m * (g +a_{1}) = 227 lb (2)[/tex]
[tex]F_{n2} = m * (g +a_{2}) = 138 lb (3)[/tex]
Replacing m by 177lb/g (a given), and rearranging, we can solve (1) for a₁, as follows:[tex]a_{1} = (\frac{227lb}{177lb} *g) - g = 0.28*g = 0.28*9.8m/s2 = 2.8 m/s2 (4)[/tex]
As it can be seen, the normal force takes a larger value in order to be compliant with the upward acceleration that opposes to gravity.In the same way, we can find the magnitude of the downward acceleration when the elevator brakes to a stop, from (3):[tex]a_{2} = (\frac{138lb}{177lb} *g) - g = -0.22*g =- 0.22*9.8m/s2 = -2.2 m/s2 (5)[/tex]
In this case, the normal force takes a lower value than at rest, due to the acceleration has the same direction as gravity.If a force is applied, but the object does
not move, what can we say about the
amount of work that is done?
A. Some work is done.
B. No work is done.
C. The work equals the force.
D. A large amount of work is done.
Answer:
doesn't move, no work is done; if a force is applied and the object moves a distance d in a direction other than the direction of the force, less work is done than if the object moves a distance d in the direction of the applied.
Answer:
B. No work is done.
Explanation:
Work is only done when the object moves in the direction of the force.
An Atwood's machine consists of two masses, m1 and m2, connected by a string that passes over a pulley. If the pulley is a disk of radius R and mass M , find the acceleration of the masses. Express your answer in terms of the variables m1, m2, R, M, and appropriate constants.
Answer:
Explanation:
Suppose m₂ is greater than m₁ and it is going down . m₁ will be going up.
Let tension in string be T₁ and T₂ . Let common acceleration of system be a
For motion of m₁
T₁-m₁g = m₁a ----- (1)
For motion of m₂
m₂g- T₂ = m₂a ------- (2)
For motion of pulley
(T₂-T₁ )R represents net torque
(T₂-T₁ )R = I x α where I is moment of inertia of disc and α is angular acceleration of disc
(T₂-T₁ )R = 1/2 M R² x a / R
(T₂-T₁ ) = M a /2
Adding (1) and (2)
(m₂-m₁)g = (m₂+m₁)a + (T₂-T₁ )
(m₂-m₁)g = (m₂+m₁)a + Ma/2
(m₂-m₁)g = (m₂+m₁+ 0.5M)a
a = (m₂-m₁)g / ( (m₂+m₁+ 0.5M)
The acceleration of the masses is [tex]\dfrac{g(m_2+m_1)}{(m_2-m_1-0.5M)}[/tex].
Given to us
Masses = m₁, m₂
The radius of the pulley = R
Mass of the pulley = M
Assumption
Let the mass m₁ > m₂. therefore, the mass m₁ is going down due to its weight while m₂ is going up.Assuming the tension in the string be T₁ and T₂, respectively.Also, the common acceleration in the system is a.Tensions in stringsWe know the acceleration due to gravity is denoted by g,
Tension in string 1, T₁[tex]T_1 = m_1(a+g)[/tex]......... equation 1
Tension in string 2, T₂[tex]T_2 = m_2(a-g)[/tex]......... equation 2
Inertia and acceleration of the pulleyThe inertia of the pulley, [tex]I = \dfrac{1}{2}MR^2[/tex]
Acceleration of the pulley, [tex]a = {\alpha }\times {R}[/tex]
Torque in the pulley[tex](T_2-T_1)R = I \times \alpha \\\\[/tex]
Substitute the values we get,
[tex][m_2(a-g)-m_1(a+g)]R = \dfrac{1}{2} MR^2 \times \dfrac{a}{R}\\\\[/tex]
[tex][m_2a-m_2g-m_1a-m_1g]R= \dfrac{1}{2} MR \times a[/tex]
[tex]m_2a-m_1a-m_2g-m_1g= \dfrac{1}{2} M \times a[/tex]
[tex]a(m_2-m_1)-g(m_2+m_1)= 0.5M \times a[/tex]
[tex]a(m_2-m_1)-0.5Ma=g(m_2+m_1)\\\\a(m_2-m_1-0.5M) = g(m_2+m_1)\\\\a = \dfrac{g(m_2+m_1)}{(m_2-m_1-0.5M)}[/tex]
Hence, the acceleration of the masses is [tex]\dfrac{g(m_2+m_1)}{(m_2-m_1-0.5M)}[/tex].
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Which device increases or decreases voltage as electricity is transmitted from power plants to homes and businesses?
generator
power line
transformer
turbine
Answer:Transformer
Explanation:All the other devices generate their own electricity apart from power line and Transformer, power line just carries electricity. A transformer can be used to step up or step down voltages from a source.
Answer:
transformer!! :)
Explanation:
What order shows increasing frequency for gamma
rays, microwaves, visible light, and X-rays?
A. gamma rays, X-rays, visible light, microwaves
B. microwaves, visible light, X-rays, gamma rays
C. visible light, gamma rays, microwaves, X-rays
D. X-rays, microwaves, gamma rays, visible light
Answer:
The answer is B: microwaves, visible light, X-rays, gamma rays
Explanation:
I had the same question and I got option B as the correct answer.
The waves arranged in their order of increasing frequency will be
Microwaves,Visible light, X-rays and Gamma rays.What order shows the increasing frequency for gamma rays, microwaves, visible light, and X-rays?Generally, frequency is the numeral of occurrences of a repeating event per unit of duration.
Therefore, gamma rays, microwaves, visible light, and X-rays will be arranged in their order of increasing frequency
In conclusion, The order is given as folllows
microwaves, Visible light, X-rays, and Gamma rays.
Option B is correct
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Electromagnetic waves used in cell phones are called
a. radio waves
b.microwaves
c. Gamma rays
d. Ultraviolet rays
Answer:
A.Radio waves
Explanation:
1. Budding is a way that some very tiny organisms can reproduce.
True
False
____________________________________
Male-female reproduction needs two parent cells to begin.
True
False
Answer:1.. true 2 false
Explanation:
Constructive interference occurs when the crest of 2 waves meet. This can occur when 2 troughs meet as well. When this occurs, water waves look
A- the same (no change)
B- larger
C- invisible
D- smaller
Answer:
B; LargerExplanation:
I took the K-12 quiz, and that was the correct answer. Hope this helped!On a spaceship designed to support a multiyear voyage to the outer planets of the solar system, plants will be grown to provide oxygen and to recycle carbon dioxide. Because the spaceship will be so far from the sun, an artificial light source will be needed to support photosynthesis. Which wavelengths of light should be used to maximize plant growth?
Answer:
A mixture of blue & red light.
Explanation:
During photosynthesis, the oxygen delivered emanates from water particles and if a weighty isotope of oxygen atom was noticed in delivered sub-atomic oxygen, the water atoms were marked with the hefty isotope.
In order to maximize the growth rate of the plant, the required wavelength of light to be used is a mixture of blue & red light. This is on the grounds that as the absorption optima of plant's photoreceptors are at wavelength frequency of red and blue light, subsequently the combination of red and blue light would be ideal for plant growth and development.
The productivity of red (650–665 nm) LEDs on plant development is straightforward on the grounds that these wavelength frequencies entirely fit with the retention pinnacle of chlorophylls and phytochrome, while the enhanced blue light presented the possibility that development under regular light could be mirrored utilizing blue and red LEDs with negligible use of energy.
An experimental procedure calls for 35.9 g sodium chloride and 15.2 g silver nitrate. What tool should be used to measure these substances?
Answer:
Electronic Balance
Explanation:
Can you please help me with this worksheet I will give BRAINLISET to whoever answers first?
A gas is stored in a sealed container of constant volume. The temperature of the gas increases.
This causes the pressure of the gas to increase
What happens to the gas molecules during this pressure increase?
A The average kinetic energy of the molecules increases.
B The average separation of the molecules decreases
The average separation of the molecules increases,
с
D
The volume of each molecule increases.
Answer:
If the gas volume is decreased, the container wall area decreases and the molecule-wall collision frequency increases, both of which increase the pressure exerted by the gas. Avogadro's law. At constant pressure and temperature, the frequency and force of molecule-wall collisions are constant.
Explanation:
As the temperature increases, the average kinetic energy increases as does the velocity of the gas particles hitting the walls of the container. The force exerted by the particles per unit of area on the container is the pressure, so as the temperature increases the pressure must also increase.
As the temperature of the gas increases, the particles gain kinetic energy and their speed increases. This means that the particles hit off the sides more often and with greater force. Both of these factors cause the pressure of the gas to increase.
What is temperature ?
Temperature is a measure of the degree of hotness of a body. The SI unit of temperature is kelvin (K).The instrument used to measure temperature is called a thermometer.
What is kinetic energy ?
Kinetic energy is a form of energy that an object or a particle has by reason of its motion. If work, which transfers energy, is done on an object by applying a net force, the object speeds up and thereby gains kinetic energy.
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A car wheel turns through 12pi in 10.7s calculate the angular speed of the wheel
Answer:
The answer should be D..
Explanation:
Plants are known as producers because they can make their own food. Which of the following provides a list of basic needs a plant must have for photosynthesis to happen?
A.
water and oxygen in the air
B.
soil, energy from the sun, and oxygen in the air
C.
energy from the sun, carbon dioxide in the air, water
D.
soil, carbon dioxide in the air, energy from the sun
HELP PLEASE
Answer:
C .energy from the sun, carbon dioxide in the air, water
hope my answer helps
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What is the gravitational potential energy of a 3 kg ball that is 1 meter above the floor?
Answer:
PE=mgh
M= Mass (kg)
G= Gravitational field strength (N/kg)
H= Hight (m)
PE= Gravitational Potential Energy (J)
Explanation:
Gravitational Potential Energy is the energy stored in a object due to its position above the Earth's surface.
The potential energy of the ball is 29.4 joules
The parameters given are;
mass= 3 kg
height= 1 meter
g= 9.8 m/s²
P.E= mgh
= 3 × 9.8 × 1
= 29.4
Hence the potential energy is 29.4 joules
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Given three different locations on Earth's surface, where will the weight of a person be greatest?
Answer:
Explanation:
In order to answer this question, we simply have to refer to the laws of the equations of gravitational mechanics.
The equation given by Newton tells us that
[tex]F = \frac{Gm_{1} m_{2} }{r^{2} }[/tex]
In the case where we compare a specific place where the Force of Gravity is greater or lesser, we focus on the term assigned to the Planet's Radius.
In the case of [tex]G, m_{1} ,m_{2}[/tex], we understand that they are constant.
We can easily notice that the more the Radius (Height seen from a viewer on the ground), the lower the force will be.
In other words, the smaller the radius in which the measurement is made with respect to the center of the earth, the greater the gravitational force.
In that order of ideas the smallest radio has South Pole, which is about 6356 km from the center of the Earth on the Equator line
A U-tube with a cross-sectional area of 1.00 cm2 is open to the atmosphere at both ends. Water is poured into the tube until the water rises part-way along the straight sides, and then 5.00 cm3 of oil is poured into one end. As a result, the top surface of the oil ends up 0.550 cm higher than the water surface on the other side of the U. What is the density of the oil
Answer:
0.89 g/cm^3 = 890 kg/m^3
Explanation:
Cross sectional area of U-tube ( A ) = 1.00 cm^2
volume of oil ( V ) = 5.00 cm^3
change between top surface = 0.550 cm
height of oil = 5 cm ( volume / area )
height of water = 5 - 0.550 = 4.45 cm
pressure at the oil-water junction = Pressure on the second side of the U-tube at same level
Po * g * Hoil = Pw * g * Hwater
Po * 5 = 1 * 4.45
∴ Density of oil ( Po ) = 4.45 / 5 g/cm^3 = 0.89 g/cm^3
In 1994, Leroy Burrell of the United States set what was then a new world record for the men’s 100 m run. He ran the 1.00 102 m distance in 9.5 s. Assuming that he ran with a constant speed equal to his average speed, and his kinetic energy was 3.40 103 J, what was Burrell’s mass?
Answer:
61.33 Kg
Explanation:
From the question given above, the following data were obtained:
Distance = 1×10² m
Time = 9.5 s
Kinetic energy (KE) = 3.40×10³ J
Mass (m) =?
Next, we shall determine the velocity Leroy Burrell. This can be obtained as follow:
Distance = 1×10² m
Time = 9.5 s
Velocity =?
Velocity = Distance / time
Velocity = 1×10² / 9.5
Velocity = 10.53 m/s
Finally, we shall determine the mass of Leroy Burrell. This can be obtained as follow:
Kinetic energy (KE) = 3.40×10³ J
Velocity (v) = 10.53 m/s
Mass (m) =?
KE = ½mv²
3.40×10³ = ½ × m × 10.53²
3.40×10³ = ½ × m × 110.8809
3.40×10³ = m × 55.44045
Divide both side by 55.44045
m = 3.40×10³ / 55.44045
m = 61.33 Kg
Thus, the mass of Leroy Burrell is 61.33 Kg
PLEASE HELP ASAP!!!
An object has a kinetic energy of 50 J and a velocity of 5 m/s, what is the mass of the
object?
A. 4 kg
B. 55 kg
С. 10 kg
D. 1 kg
Answer:
0.5mv^2=50, v=5, 25/2×m=50, m=50×2/25, So, the answer is 4
A temperature scale has an upper fixed point of 260mm and the lower fixed point of 50mm.what will be the reading on this scale when the thermometer read 125°F
Answer:
the reading on the scale is 158.5 mm.
Explanation:
Given;
upper fixed point of the temperature scale, x₁ = 260 mm
lower fixed point of the temperature scale, x₂ = 50 mm
upper temperature scale, T₁ = 212 °F
lower temperature scale, T₂ = 32 °F
thermometer reading, t = 125 °F, let the reading on the scale = x
Interpolate as follows to determine the value of "x"
[tex]\frac{X_1 - X}{X_1-X_2} = \frac{T_1-t}{T_1-T_2} \\\\\frac{260-X}{260-50} = \frac{212-125}{212-32} \\\\\frac{260 -X}{210} =\frac{87}{180} \\\\180(260-X) = 87(210)\\\\46800 -180 X = 18270 \\\\180X = 46800-18270\\\\180X = 28530\\\\X = \frac{28530}{180} \\\\X = 158.5 \ mm[/tex]
Therefore, the reading on the scale is 158.5 mm.
We observe that a moving charged particle experiences no magnetic force. From this we can definitely conclude that: (A) No magnetic field exists in that region of space. (B) The particle must be moving parallel to the magnetic field. (C) Either no magnetic field exists or the particle is moving parallel to B. (D) Either no magnetic field exists or the particle is moving vertical (perpendicular) to B.
Answer:
(C) Either no magnetic field exists or the particle is moving parallel to B.
Explanation:
The moving charged particle tends to show no magnetic forces. Due to its moving in the same direction and will be parallel to the field. As when the magnetic fed and charged particle velocity is parallel then there will be no force. As the magnetic field are made by the generation of the current with the field line concentric to the current-carrying wire.they enjoy being alone for quit small time
Two copper rods are rubbed together will they become charged
Answer:
Explanation:When insulating materials rub against each other, they may become electrically charged . Electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. The material that gains electrons becomes negatively charged.
A 105-kg rubber mat is pushed on a dry concrete floor. What is the coefficient of static friction, if the force required to start the mat sliding is 1030 N?
Answer:
[tex]\mu=1[/tex]
Explanation:
Given that,
Mass of a rubber mat, m = 105 kg
We need to find the coefficient of static friction, if the force required to start the mat sliding is 1030 N.
The applied force is given by :
[tex]F=\mu mg\\\\\mu=\dfrac{F}{mg}\\\\\mu=\dfrac{1030}{105\times 9.8}\\\\\mu=1[/tex]
So, the required coefficient of static friction is equal to 1.
Which of the following parallel plate diagrams would have the greatest electric fields between them?
The greatest electric field between them is Option B.
An electric field is the physical subject that surrounds electrically charged particles and exerts a force on all other charged debris inside the area, either attracting or repelling them. It also refers back to the bodily field of a machine of charged particles.
Reasoning:-
Electric field = Kq/r²
Since the distance is inversely proportional to the square root of the distance between them. therefore decreasing the distance electric field will be the greatest. Hence Option B.
The electrical field is defined mathematically as a vector discipline that can be related to each point in space, the force in step with unit charge exerted on a fine take a look at the price at rest at that factor. the electric field is generated by the electrical rate or through time-varying magnetic fields. electric fields provide us with the pushing force we need to set off the contemporary float.
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15. Which tectonic boundary would have many normal faults associated
with it?
A. Convergent
B. Divergent
C. Transform
A5 N object at a height has gravitational potential energy of 30 J. What is the height of the object?
30=5×h then divide both sides by 5 you will get h=6m
If a 5 N object at a height has a gravitational potential energy of 30 J , then the height of the object would be 6 meters.
What is mechanical energy?Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total potential energy stored energy in the system which is represented by total potential energy.
As given in the problem a 5 N object at a height has gravitational potential energy of 30 J, then we have to find the height of the object.
Similarly, the total gravitational potential energy of the object,
PE = m × g × h
30 = 5 × h
h = 30 / 5
h = 6 meters
Thus, if a 5 N object at a height has a gravitational potential energy of 30 J, then the height of the object would be 6 meters.
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can someone pls tell me what a force diagram is
How much work is done to increase the speed of a 1.0 kg toy car by 5.0 m/s?
50 J,
12.5 J,
25 J,
49 J
Answer:
The correct option is (b).
Explanation:
We need to find the work done to increase the speed of a 1 kg toy car by 5 m/s.
We know that, the work done is equal to the kinetic energy of an object i.e.
[tex]W=\Delta K\\\\W=\dfrac{1}{2}mv^2\\\\W=\dfrac{1}{2}\times 1\times 5^2\\W=12.5\ J[/tex]
So, 12.5 J of work is done to increase the speed of a 1.0 kg toy car by 5.0 m/s.
You push
on box A with a horizontal
100-N force (Fig. Q4.31). Box A
weighs 150 N, and box B
weighs 50 N. Is the force that
box A exerts on box B equal to 100 N, greater than 100 N, or less than 100 N? Explain.