If a weightlifter lifts 2000 N to a height of 2 meters in 4 seconds. The power is 1000 watts.
What is Power?The word "power" is one we hear a lot, just like "energy." It can mean a variety of things in daily life. But in physics, it has a very specific significance. It serves as a metric for how quickly something is finished (or similarly, at which energy is transferred).
The standard unit for measuring power is the watt, which is denoted by the symbol text, W, and end text. The name of the unit pays homage to Scottish industrialist and inventor James Watt. Undoubtedly, you come across the term "watt" regularly in daily life. The power output of electrical appliances like light bulbs and stereos is frequently advertised in watts.
According to the question,
Power = [tex]workdone/time[/tex]
Power = (2000×2)/4
Power = 1000 watt.
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Two train whistles have identical frequencies of 1.85 102 Hz. When one train is at rest in the station and the other is moving nearby, a commuter standing on the station platform hears beats with a frequency of 8.00 beats/s when the whistles operate together. What are the two possible speeds that the moving train can have
Answer:
Explanation:
frequency of whistle = 1.85 x 10² = 185 Hz
frequency of beat heard = 8 beat /s . No of beat produced is equal to difference of frequencies of two sound source . Here difference is created due to Doppler effect . One of the train is moving so it will have apparent frequency which is different one from its original frequency .
When the moving train is approaching the observer , its frequency will be higher . As beat is heard at the rate of 8 beats / s , apparent frequency of approaching train will be 185 + 8 = 193 Hz .
Applying Doppler's formula of apparent frequency ,
193 = 185 x V / ( V - v ) , where V is velocity of sound and v is velocity of train .
193 V - 193 v = 185 V
193 v = 8 V
v = 8 x V / 193
= 8 x 343 / 193
= 14.21 m /s
Second possibility is that apparent velocity is less ie 185 - 8 = 177 Hz
In that case moving train will be moving away from observer . If its velocity be v
177 = 185 x V / ( V + v )
177 V + 177 v = 185 V
v = 8 x 343 / 177
= 15.50 m /s .
A cylindrical pulley with a mass of 4.4 kg, radius of 0.816 m and moment of inertia 1 2 M r2 is used to lower a bucket with a mass of 3.1 kg into a well. The bucket starts from rest and falls for 2.9 s. r M m What is the linear acceleration of the falling bucket
Answer:
5.85 m/s²
Explanation:
Mass of pulley (M) = 6.8 kg, mass of bucket (m) = 1.5 kg, radius of pulley (r) = 0.816 m, acceleration due to gravity (g) = 10 m/s².
Let the tension exerted on the pulley be T and the angular acceleration be α,
The angular acceleration (α) = a / r; where a is the linear acceleration.
mg - T = ma
T = m(g - a)
Also, for the disk:
Tr = Iα
I = moment of inertia = 0.5Mr²
m(g - a)r = 0.5Mr²(a/r)
m(g - a)r = 0.5Mra
2m(g - a) = Ma
2mg - 2ma = Ma
Ma + 2ma = 2mg
a(M + 2m) = 2mg
a = 2mg / (M + 2m)
Substituting:
a = 2(3.1 kg)(10 m/s²) / (4.4 + 2(3.1))
a = 5.85 m/s²
A rock accelerated 4.8 m/s² as it was kicked with a force of 1.79 Newtons. What was the mass of the rock?
2.68 kg
0.37 kg
6.59 kg
3.01 kg
Which choices describe advantages of wind energy over fossil fuels?
Select all that apply.
doesn't emit pollutants
renewable
freely available
O releases carbon dioxide instead of carbon monoxide
The advantages of wind energy over fossil fuels are that it does not emit pollutants, it is a renewable source of energy and it is a freely available source of energy.
What is wind energy?
The process that describes the generation of wind power or the mechanical power using the flow of wind itself, is known as wind energy.
Following are the advantages of wind energy over fossil fuels -
Free source of fuel.One of the cleanest forms of energy.Advance technologies are used for its extraction.Does not disrupt any sort of farmland operations.It is a clean fuel source and does not emit pollutants.It is a renewable source of energy.Thus, we can conclude that the advantages of wind energy over fossil fuels are that it does not emit pollutants, it is a renewable source of energy and it is a freely available source of energy.
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A ball is thrown up into the air. The time that it takes to go up equals
Answer:
The time it takes the ball to rise equals the time it takes to fall.
Explanation:
because what goes up at some point must come down
A 2 kg melon is balanced on your bald uncle’s head. His son, Throckmorton, shoots a 50 g (0.05kg) arrow at it with a speed of 30 m/s. The arrow passes through the melon and emerges with a speed of 18 m/s. Find the speed of the melon as it flies off the man’s head.
Answer:
The speed of the melon as it flies off the man’s head is 0.3 m/s.
Explanation:
Given;
mass of the melon, m₁ = 2 kg
initial speed of the melon, u₁ = 0
mass of arrow, m₂ = 0.05 kg
initial speed of the arrow, u₂ = 30 m/s
final speed of the arrow, v₂ = 18 m/s
let v₁ be the final speed of the melon as it flies off the man's head.
Apply the principle of conservation of linear momentum;
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
2(0) + 0.05 x 30 = 2v₁ + 0.05 x 18
1.5 = 2v₁ + 0.9
2v₁ = 1.5 - 0.9
2v₁ = 0.6
v₁ = 0.6 / 2
v₁ = 0.3 m/s
Therefore, the speed of the melon as it flies off the man’s head is 0.3 m/s.
An uncharged capacitor and a resistor are connected in series with a switch and a 12 V battery. At the instant the switch is closed, the voltage across the resistor is
Answer:
V = 12 V
Explanation:
Since a capacitor can't change the voltage between its plates instantaneously, this means that just after the switch is closed, the voltage through the capacitor is zero.So, the current that flows in this moment is the same that would flow in a series circuit with only one resistor connected to the battery.Applying KVL to the circuit (neglecting the presence of the capacitor which can be replaced by a short circuit just after closing the switch), the voltage through the resistor must be equal to the one of the battery, i.e., 12 V.why all traveller prefer to travel easily in the morning and night and not when the sun is hot
Answer:
Travelers prefer to travel in morning because arthat time the temperature ️ is not too hot and they can easily travel here and there without any problem. and they also prefer to travel in night because moderate temperature ....
10/12
11.
You drive the 10 miles to the mall at an average speed of 40 mph. On
the way home, you hit severe traffic and had to drive at an average
speed of 10 mph. What is your average speed for the trip?
An electric current is made up of _____ charged electron.
An Electric current is made up of a negatively charged electron.
What is an Electric current?Electric current is defined as the flow of charge per unit time in a conductor. It is a scalar quantity.
I=Q/T where,
I= Electric Current
Q= Flow of charge and,
T=Time
The electron consists of a negative charge and the flow of electrons takes place from the negative end to the positive end, but the current flow in the circuit takes place from positive to negative, which is opposite to the direction of the flow of electrons.
The current flow takes place due to the Potential difference (V).
SI unit of Electric current is Ampere.
1 ampere= 1c/1s and
1 mA= [tex]10^{-3}[/tex] A.
An ammeter is a device to measure the electric current in the circuit, and it is connected in series.
Hence, electric current is made up of negatively charged electrons.
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How does vegetation in the soil affect the rate of erosion
Answer:
Plants slow down water as it flows over the land and this allows much of the rain to soak into the ground. Plant roots hold the soil in position and prevent it from being blown or washed away. Plants break the impact of a raindrop before it hits the soil, reducing the soil's ability to erode.
Explanation:
An object has a constant velocity of 20 m/s to the north, and there are two
forces acting on it. What is this situation called?
O A. Force equilibrium
B. Inertia equilibrium
C. Dynamic equilibrium
D. Static equilibrium
Answer:
It's Dynamic Equilibirum
Explanation
A wire of cross-sectional area 5.00 106 m2 has a resistance of 1.75 O. What is the resistance of a wire of the same material and length as the first wire, but with a cross-sectional area of 8.75 106 m2
Answer:
the resistance of the second wire is 1 ohm.
Explanation:
Given;
cross sectional area of the first wire, A₁ = 5.00 x 10⁶ m²
resistance of the first wire, R₁ = 1.75 ohms
cross sectional area of the second wire, A₂ = 8.75 x 10⁶ m²
resistance of the second wire, R₂ = ?
The resistance of a wire is given as;
R ∝ [tex]\frac{L}{A}[/tex]
Since the length of the two wires is constant
R₁A₁ = R₂A₂
[tex]R_2 = \frac{R_1A_1}{A_2} \\\\R_2 = \frac{1.75\ \times \ 5.00\times 10^6}{8.75\times 10^6} \\\\R_2 = 1 \ ohm[/tex]
Therefore, the resistance of the second wire is 1 ohm.
liquids have higher coefficents of expansion than solids do in general. ture or false worth 29 points!
Answer:
true
Explanation:
What causes an electromagnet to create a magnetic field?
A.The Earth's magnetic field.
B.The poles are attracted to each other.
C.The iron is wrapped with a coiled wire.
D.There is a current flowing through the wire.
Answer:
D
Explanation:
Have a great day ;)
The motion of a ball on an inclined plane is described by the equation Ax = 1/2a(At)^2. This statement implies which of the following quantities has a value of zero?
Answer: Initial Velocity
Explanation:
The formula is:
Δx = Vit + 1/2at^2
Therefore the initial velocity is zero
How is the chemical bonding within a molecule of carbon dioxide (CO2) different from the chemical bonding within a crystal of iron (Fe)?
A.
In an iron crystal, the atoms are joined by sharing electrons. In carbon dioxide, atoms of carbon and oxygen are held together by freely moving electrons.
B.
In a carbon dioxide molecule, atoms of carbon and oxygen are joined by sharing electrons. In an iron crystal, the atoms are held together by freely moving electrons.
C.
In an iron crystal, the atoms are joined by their opposite electrical charges. In carbon dioxide, atoms of carbon and oxygen are held together by freely moving electrons.
D.
In a carbon dioxide molecule, atoms of carbon and oxygen are joined by their opposite electrical charges. In an iron crystal, the atoms are held together by freely moving electrons.
Answer:
I'ts B
Explanation:
:p
The chemical bonding within a molecule of carbon dioxide (CO2) different from the chemical bonding within a crystal of iron (Fe) in a carbon dioxide molecule, atoms of carbon and oxygen are joined by sharing electrons. In an iron crystal, the atoms are held together by freely moving electrons. Therefore, option B is correct.
What is chemical bonding ?The term chemical bonding is defined as the formation of a chemical bond between two or more atoms, molecules, or ions to form a chemical compound.
There are three main types of chemical bonding that are ionic bonding, covalent bonding, and metallic bonding.
The chemical bonding within a molecule of carbon dioxide (CO2) different from the chemical bonding within a crystal of iron (Fe) because in a carbon dioxide molecule, atoms of carbon and oxygen are joined by sharing electrons. In an iron crystal, the atoms are held together by freely moving electrons.
Thus, option B is correct.
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If you apply 3 times the force for 4 times the distance, how much does your work increase?
Select the correct answer.
A car is moving at a constant speed along a straight line. Which statement is true about the forces acting on the car?
ОА.
The net force acting on the car from all directions is zero.
o
B.
The net force acting on the car is greater than the car's weight.
O c.
The net force acting on the car is in the direction of the car's motion.
OD.
The net force acting on the car is in the opposite direction of the car's motion.
Answer:
ОА.
The net force acting on the car from all directions is zero.
Explanation:
Constant speed along a straight line
It means constant magnitude of velocity without chainging direction
It means constant velocity. Which means acclecration is zero
By Newton's second law:
[tex]F=ma[/tex]
Net force is also zero
How much money can be found in the pockets/purses of the 250 students in a class if no student may carry 2 identical banknotes with them? (Give the range: minimum – maximum. Ignore coins)
does the sabre-tooth currirulum still exist at present?give examples of your evidence
Answer: Should the sabre tooth curriculum really exist at the moment? As far as I am concerned, the sabre tooth program should remain, because our school system needs to help people know how to do complex activities on their own and we let them do activities that will help them develop their brains as well as their skills.
Great schools promote better teaching because they have the most experience of teaching practice and are accountable for executing the instruction in the classroom. Teacher engagement is also vital for the effective and substantive implementation of the curriculum.
Sources: files.eric.ed.gov and James Kennedy Monash
magnitude of the normal force exerted by en in the figure below. What is the
A suitcase of mass mis resting on an inclined plane
?
Answer:
B
Explanation:
Reason is that the suitcase is exerted downward and when it moves downward the equation is mgsin tita
where is a positive constant and is the acceleration due to gravity, is a model for the velocity of a body of mass that is falling under the influence of gravity. Because the term represents air resistance, the velocity of a body falling from a great height does not increase without bound as time increases. Use a phase portrait of the differential equation to find the limiting, or terminal, velocity of the body. Explain your reasoning.
Answer:
[tex]v_{T}[/tex] = [tex]\frac{b}{m}[/tex] g
Explanation:
For this exercise we use Newton's second law
∑ F = m a
where they relate it is
a = dv / dt
v = dx / dt
in this case we have two forces: the weight of the body and the friction of the air
fr -W = m a
there are several ways to approximate the friction force in a fluid, if the velocity of the body is low we can use
fr = b v
for high speeds, higher power speed terms are entered
we substitute
b v - m g = m dv / dt
[tex]\frac{dv}{dt}[/tex] = [tex]\frac{b}{m}[/tex] v -g
We can see that as the speed increases, we reach the point that the term on the right is zero, at this point there is no acceleration, therefore the speed is constant and is called the terminal velocity.
0 =[tex]\frac{b}{m} \ v_T[/tex] -g
[tex]v_{T}[/tex] = [tex]\frac{b}{m}[/tex] g
the constant b is given by the conditions of the air, pressure, density and temperature
Which choice describes a concern with wind energy?
O may harm bird and bat populations
o negative impact on river ecosystems
O turbines are cheaply made
O could interfere with pollen distribution
A concern which is related to the wind energy is that these could interfere with the pollen distribution. Thus, the correct option is D.
What is Wind energy?Wind power or wind energy is mostly used in the wind turbines to generate electricity. The wind power is a popular, sustainable, renewable energy source which has a much smaller impact on the surrounding environment than that of burning fossil fuels.
Some disadvantages of wind energy include noise and visual pollution, wind power is not a remote power, and the effects or impact on the environment including interference with the pollen distribution.
Therefore, the correct option is D.
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a. Describe the big bang theory. (1 point) b. Match each model of the universe with the future it predicts. (1 point) A. Closed B. Flat C. Open _____ The universe will stop expanding but will not collapse. _____ The universe will continue to expand forever. _____ The universe will stop expanding and then collapse back to its point of origin. c. Match each observation to the conclusion it supports in the big bang theory. (1 point) A. Light from other galaxies is shifted toward the red end of the spectrum. B. Cosmic background radiation appears uniform across the sky. C. The amount of helium in the universe matches predictions. _____ Nucleosynthesis of light elements occurred shortly after the expansion of the original ball of energy. _____ The universe is expanding. _____ The universe began from a single point.
Answer:
A)
The Big Bang is the earliest known event in the observable Universe, its earliest known phase of evolution, and the name of the model for this process. According to this scenario, the Big Bang took place around 13.800 million years ago, when the known Universe emerged from very dense and hot matter. This theory is based on observations showing that space is expanding from an initial state where all the matter in the universe had a very high density and temperature, to a more cold and stable one.
B)
A. Closed. The universe will stop expanding and then collapse back to its point of origin.
B. Flat. The universe will stop expanding but will not collapse.
C. Open. The universe will continue to expand forever.
Should heinz have stolen the drug? Why or why not?
Heinz should steal the medicine, because saving a human life is a more fundamental value than the property rights of another person.
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A battery connected to two wires in parallel. Both wires are made of the same material and are of the same length, but the diameter of wire A is twice the diameter of wire B.
True or False for the following:
1) The resistance of wire B is four times as large as the resistance of wire A.
2) The power dissipated in wire A is 16 times the power dissipated in wire B.
3) The voltage drop across wire B is larger than the voltage drop across wire A.
4) The resistance of wire B is twice as large as the resistance of wire A.
5) The current through the battery is five times larger than the current through wire B.
Answer:
true 1
2 is false 2. 3 . 4. 5
Explanation:
For this exercise, let's calculate the different parameters and analyze the corresponding statements.
the resistance of each wire
R = ρ [tex]\frac{L}{A}[/tex]
wire B.
has a diameter of d₀
therefore its radius is r₀ = d₀ / 2
the area is A = pi r₀²
A = π d₀²/ 4
we subtitle
Ro = ρ [tex]\frac{L \ 4}{\pi d_o^2}[/tex]
R_b = R₀
wire A
the diameter is d = 2d₀
therefore the radius is r = d/2
r = d₀
resistance is
R_a = ρ [tex]\frac{L}{\pi d_o}[/tex]
R_a = 4 R₀
when examining the answers
1 is true
4 is false
Now let's calculate the power
P = V I
V = I R
P = V² / R
as they indicate that the cables are connected in parallel, the voltage in them is the same, therefore the potency depends on the resistance
wire B
P = V² / R_b
P_b = V² / R₀
wire A
P_a = v² / R_a
P_a = V² / 4R₀
P_a = ¼ P_b
2 is false
in a parallel circuit the waves are the same therefore
3 False
ohm's law is
V = I r
I = V / R
wire B
I_b = V / R_b
I_b = V / Ro
wire
I_a = V / R_a
I_a = V / 4 Ro
I_a = ¼ I_a
5 is false
A ball is Thrown Upward with An initial velocity of 30 m/s , How high does it rise from the ground when the ball reaches the highest Point ? And how long does it take to fall down to half of its height
Answer:
The maximum height reached by the ball is 45.92 mTime taken to fall down to half of its height is 2.2 sExplanation:
Given;
initial velocity of the ball, u = 30 m/s
final velocity of the ball at the highest point, v = 0
The maximum height reached by the ball is calculated as;
v² = u² - 2gh
where;
h is the maximum height reached by the ball
0 = 30² - (2 x 9.8)h
19.6h = 900
h = 900 / 19.6
h = 45.92 m
Time taken to fall to half of its height is calculated as;
when falling down, the final velocity v becomes the initial velocity = 0.
Apply the following kinematic equation;
h = ut + ¹/₂gt²
h = 0 + ¹/₂gt²
h = ¹/₂gt²
where;
h = 45.92 m is the maximum height reached
half of h = 45.92 / 2 = 22.96 m
22.96 = ¹/₂gt²
[tex]t = \sqrt{\frac{2h}{g} } \\\\t = \sqrt{\frac{2\times 22.96}{9.8} }\\\\t = 2.2 \ s[/tex]
A 5 kg block rests on a rough horizontal table. A rope is
attached to the block and is pulled with a force of 11N to the
left. As a result, the block accelerates at 2 m/s2. The coefficient
of kinetic friction between the block and the table is (round
to the nearest hundredth)
Answer:
Approximately [tex]0.02[/tex] (assuming that [tex]g = 9.81\; \rm N \cdot kg^{-1}[/tex], and that the block was initially moving to the left.)
Explanation:
Apply Newton's Second Law to find the net force on this block.
Mass of this block: [tex]m = 5\; \rm kg[/tex].
Acceleration of this block: [tex]a = 2\; \rm m \cdot s^{-2}[/tex].
[tex]\begin{aligned}\text{Net force} &= m \cdot a \\ &= 5\; \rm kg \times 2\; \rm m \cdot s^{-1} = 10\; \rm N\end{aligned}[/tex].
The block is moving and accelerating towards the left. Hence, friction (which opposes motion) would be towards the right and would be opposite to the direction of the [tex]11\; \rm N[/tex] pulling force.
Therefore, the expression for the net force on this object would be:
[tex](\text{Net force} ) = (\text{Pulling force}) - (\text{Friction})[/tex].
[tex]10\; \rm N = 11\; \rm N - (\text{Friction})[/tex].
Hence:
[tex]\text{Friction} = 11\; \rm N - 10\; \rm N = 1\; \rm N[/tex].
The question states that this table is horizontal. Weight of the block (downwards) and normal force from the table (upwards) are the only two forces on this block in the vertical direction. Hence, the magnitude of the normal force on this block would equal to that of the weight of the block:
[tex]\begin{aligned} |\text{Normal force}| &= |\text{Weight}| \\ &= m \cdot g \\ &= 5 \; \rm kg \times 9.81\; \rm N \cdot kg^{-1} = 49.05\; \rm N\end{aligned}[/tex].
Calculate the constant of kinetic friction between this block and the table:
[tex]\begin{aligned}\mu_{\text{k}} &= \frac{\text{Friction}}{\text{Normal force}} \\ &= \frac{1\; \rm N}{49.05\; \rm N} \approx 0.02\end{aligned}[/tex].
What is the velocity of a car that travels from mile marker 32 on I-10 to mile marker 312 on I-10 in a time of 2 hours and 45 minutes? SYW!
Answer:
101.81818 MPH
Explanation: