Answer:
Current drawn = 0.417 A (rounded to 3 significant figures)
Resistance = 576Ω (rounded to 3 significant figures)
Explanation:
Current = Power ÷ Voltage
Current = 100W / 240V
∴ Current = 0.416666666.... = 0.417A
Resistance = Voltage ÷ Current
Resistance = 240 ÷ 0.417
∴ Resistance = 575.539 = 576Ω
The first stage of a space vehicle consumed fuel and oxidizer at the rate of 1.75 x 104 kg/s, with an exhaust speed of 2.40 x 103 m/s. Find the acceleration (in m/s2) of the vehicle just as it lifted off the launch pad on the Earth, if the vehicle's initial mass was 3.00 x 106 kg. (Note: You must include the force of gravity to solve the problem.)
Answer:
[tex]a=4.19 m/s^{2}[/tex]
Explanation:
In order to solve this problem, we must first draw a free body diagram of the situation. (See attached picture)
from this diagram, we can do the following sum of forces:
[tex]\sum F=ma[/tex]
where m is the mass of the rocket and a is its acceleration.
[tex]F_{e}-mg=ma[/tex]
where [tex]F_{e}[/tex] is the force of exhaust. We can solve this for the acceleration, so we get:
[tex]a=\frac{F_{e}-mg}{m}[/tex]
we can find the force of exhaust by using the momentum formula:
Ft=mv
so we can solve this for the force:
[tex]F_{e}=\frac{mv}{t}[/tex]
the problem already tells us what m/t is equal to, so we can directly substitute:
[tex]F_{e}=(1.75x10^{4}kg/s)(2.40x10^3m/s)[/tex]
which yields:
[tex]F_{e}=42x10^6 N[/tex]
So we can now substitute:
[tex]a=\frac{42x10^6N-(3x10^6kg)(9.81m/s^{2})}{3x10^6kg}[/tex]
so:
[tex]a=4.19 m/s^{2}[/tex]
When the car is sitting and not moving, inertia is in control and ___
exists.
Which of the following best describes a galaxy?
A. A spiral shape of stars
B. Large groups of stars held together by gravity
C. The Milky Way
D. The rotation of many planets and stars
Answer:
B-Large groups of stars held together by gravity
Explanation:
35. The work function of
Caesium is 2.14 e V. The
threshold frequency for
Caesium is
*
Answer:
[tex]5.16*10^{14}Hz[/tex]
Explanation:
1 eV = 1.6 * 10⁻¹⁹ J
The work function is the minimum energy required to cause the photo-emission of electrons. The work function is dependent on the type of metal.
Whereas the threshold frequency is the minimum frequency of light required to produce the work function energy. The work function is given by:
[tex]E=hf_o\\\\Where\ E = work \ function, h=plank's\ constant=6.63*10^{-34}Js,f=threshold\ frequency.\\\\Given\ that \ E=2.14eV, hence:\\\\E=hf_o\\\\2.14eV=6.63*10^{-34}Js*f_o\\\\f_o=\frac{2.14\ *1.6*10^-19}{6.63*10^{-34}Js} \\\\f_o=5.16*10^{14}Hz[/tex]
The diagrams below represent different ways heat can be transferred on Earth. The arrows in the diagrams show the direction of heat transfer.
Which of the following shows the primary way heat is transferred in each diagram?
A)
Diagram X = conduction; Diagram Y= convection; Diagram Z = radiation
B)
Diagram X = convection; Diagram Y = radiation; Diagram Z = conduction
C)
Diagram X = convection; Diagram Y = conduction; Diagram Z = radiation
Answer:
c
Explanation:
heat radiates off of thing most of the time
Diagram X = convection; Diagram Y = conduction; Diagram Z = radiation
What are the 3 ways heat is transferred on Earth?radiation.conduction.convection.What is the direction of flow of heat transfer?The direction of heat transfer is first from the lower-temperature object to the higher-temperature object, then back again to the lower-temperature object, and so forth, until the objects are in thermal equilibrium.
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A ball starts from rest, it rolls down a ramp and reaches the ground after 4 seconds. The final velocity when it reaches the ground is 7.0 meters/second. What is initial velocity and its acceleration?
If it starts at rest the initial velocity is 0.
For an acceleration, a, and time, t, the velocity is v=at. Since at t=4, v=7, then a=7/4=1.75m/s^2
The initial velocity and the acceleration of the ball start from rest, it rolls down a ramp and reaches the ground after 4 seconds are 0 m/s and 3.5 m / s² respectively.
What is velocity?The rate of change of an object's location when viewed from a particular angle and measured in a particular unit of time is known as its velocity.
The average speed of a point for a set period of time while it travels a predetermined distance along its path is equal to the distance traveled divided by the travel time. A train, for instance, moves at an average speed of 50 km/h when it travels 100 km in two hours.
Given:
A ball starts from rest, it rolls down a ramp and reaches the ground after 4 seconds. The final velocity when it reaches the ground is 7.0 m/s,
Calculate the acceleration as shown below,
[tex]v = u + at[/tex]
7 = u + a × 4
7 = u + 4a
As it starts from rest, then the initial velocity is 0 m/s
a = 7/4 or 3.5 m / s²
Thus, the acceleration is 3.5 m / s² and the initial velocity is 0 m/s.
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Which players are usually the fasted on the team, run the offensive, and shoot from the perimeter of the court?
Forward
Mid-fielder
Guard
Center
Answer:
i think guard but not sure
Which has the most energy stored as heat?
a cup of ice
a bathtub of cold water
a cup of boiling water
a bucket of ice water
1. A small metal weight is suspended from a spring
scale as shown in this illustration
Spring Scale
N
1.0
2.0
3.0
4.0- The spring is measure here at 4.0 N
5.0
6.0
7.0
8.0
9.0
10.0
• What is the gravitational force acting on the weight? Explain.
• What is the net force acting on the weight? Explain.
Answer:
a) W = -4N, b) F_net = 0
Explanation:
The suspended weight of the spring ladder is subjected to two forces: the elastic force of the spring directed downwards and the gravitational force directed downwards.
[tex]F_{e}[/tex] - W = 0
F_{e} = W
F_{e} = W = 4 N
a) the gravitational force is the weight of the body
W = -4N
b) as the system is in equilibrium, the net force is zero
F_net = 0
It is a general exercise that we do before practicing sports activities
worm-up or cool down
It is called a warm-up.
Answer:
We do warm-ups before we exercise. We do cool-downs after we exercise.
Explanation:
Warming up can help you get ready to do the actual exercise, so you are prepared.
Can someone help me god will bless you
Answer:
Symbolic culture, or nonmaterial culture, is the ability to learn and transmit behavioral traditions from one generation to the next by the invention of things that exist entirely in the symbolic realm. Symbolic culture is studied by archaeologists, social anthropologists and sociologists.
Explanation:
i hope this helped!
6. Calculate the total resistance in a series circuit with a fan (3 ohms) and 3 lights (1 ohms each).
15 ohms
6 ohms
12 ohms
9 ohms
PLS HURRY ILL MARK BRAINLYEST
Answer:
R_eq = 6 Ω
Explanation:
In a series circuit the current is constant throughout the circuit and the resistance is the sum of all the resistances in it.
R_eq = ∑ [tex]R_{i}[/tex]
in this case we have
R_eq = R₁1 + 3 R₂
where R₁ is the resistance of the fan and R₂ the resistance of each light, we must clarify that we will assume that the resistance of the lights does not change with temperature
let's calculate
R_eq = 3 + 3 1
R_eq = 6 Ω
Answer:
The awnser is 6 ohms.
Explanation:
Answer the question below:
Answer:
D) the decay rates of radioactive uranium and lead
Explanation:
As we know that when she found the substance it must have some fixed ratio of radioactive uranium and Lead in that substance.
Here since Uranium is radioactive substance so it will continuously convert into Lead and this ratio will change with time
So here we can say that the ratio of radioactive uranium and lead will depend on its decay rate
now to find the age of the substance we can find the present ratio of lead and uranium in that substance and then compare it with freshly prepared substance.
so by the formula
we can find the age of the sample
Answer:
Its D
Explanation:
Why are stars considered to be the building blocks of the universe?
A. Stars are found throughout the galaxy
B. Stars become novas, supernovas, and Black Holes
C. Nuclear fusion within stars creates needed elements for he universe
D. The sun is a star
If an element has a mass number of 200 and an atomic number of 80, how many neutrons does the element have?
A. 80
B. 280
C. 120
D. 200
Answer:
If I say the correct answer is B.280
simple but not plagiarized answer for "what is forces and motion?"
Why does the sun predictably hold the asteroid and the Earth in orbit?
Answer:
The force of gravity
Explanation:
The sun is able to predictably hold the asteroid and the earth in orbit by the force of gravity is possesses.
During the earth formation of the solar system, the sun captured the earth and other planetary bodies within its region of influence.
Based on Newton's law of universal gravitation, the force of gravity between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. The sun is a very massive body and due to the mass of the earth and other bodies, they are captured by the attractive gravitational force into its orbit.When a piece of metal is heated to high temperatures, it begins to glow red,
and then white, as its temperature increases. Does this phenomenon provide
evidence for the wave model or the particle model of light? Why?
A. The wave model, because the wavelengths of emitted radiation
keep changing
O B. The wave model, because the wavelengths of emitted light depend
on the metal's temperature
O C. The particle model, because the metal is emitting packets of light
at specific wavelengths
O D. The pticle model, because the metal is only absorbing radiation
of specific frequencies
Answer:
The particle model, because the metal is only absorbing radiation
of specific frequencies
Explanation:
The heating of a metal is an example of blackbody radiation. Blackbody radiation refers to the spectrum of light emitted by any heated object; common examples include the heating element of a toaster and the filament of a light bulb. The spectral intensity of blackbody radiation peaks at a frequency that increases with the temperature of the emitting body(Encyclopedia Britianica).
Max Plank proffered explanation to black body radiation by assuming that the oscillators in the heated body emit or absorb energy in discrete frequencies given by E=hf. Hence the energy was directly proportional to the frequency of the oscillator.
A rocket for use in deep space is to have the capability of boosting a total load (payload plus the rocket frame and engine) of 3.25 metric tons to a speed of 10,000 m/s. It has an engine and fuel designed to produce an exhaust speed of 2400 m/s. How much fuel plus oxidizer is required (in metric tons)
Answer:
13.54 tons
Explanation:
Let f be the amount of fuel oxidizer needed
v be the speed
The relationship between them is inverse in nature i.e
f ∝ 1/v
f = k/v
If a rocket for use in deep space is to have the capability of boosting a total load (payload plus the rocket frame and engine) of 3.25 metric tons to a speed of 10,000 m/s, then f = 3.25 when v = 10,000
Substitute and get k
k = fv
k = 3.25 * 10,000
k = 32500
To get the amount of fuel oxidizer required to produce a speed of 2400m/s, we will find f when v = 2400m/s
Recall that f = k/v
f = 32500/2400
f = 13.54 metric tons
Hence the fuel plus oxidizer that will be required is 13.54 tons
Planet 1 orbits Star 1 and Planet 2 orbits Star 2 in circular orbits of the same radius. However, the orbital period of Planet 1 is longer than the orbital period of Planet 2. What could explain this
Answer:
The mass of Star 2 is Greater than the mass of Start 1. (This, if we suppose the masses of the planets are much smaller than the masses of the stars)
Explanation:
First of all, let's draw a free body diagram of a planet orbiting a star. (See attached picture).
From the free body diagram we can build an equation with the sum of forces between the start and the planet.
[tex]\sum F=ma[/tex]
We know that the force between two bodies due to gravity is given by the following equation:
[tex]F_{g} = G\frac{m_{1}m_{2}}{r^{2}}[/tex]
in this case we will call:
M= mass of the star
m= mass of the planet
r = distance between the star and the planet
G= constant of gravitation.
so:
[tex]F_{g} =G\frac{Mm}{r^{2}}[/tex]
Also, if the planet describes a circular orbit, the centripetal force is given by the following equation:
[tex]F_{c}=ma_{c}[/tex]
where the centripetal acceleration is given by:
[tex]a_{c}=\omega ^{2}r[/tex]
where
[tex]\omega = \frac{2\pi}{T}[/tex]
Where T is the period, and [tex]\omega[/tex] is the angular speed of the planet, so:
[tex]a_{c} = ( \frac{2\pi}{T})^{2}r[/tex]
or:
[tex]a_{c}=\frac{4\pi^{2}r}{T^{2}}[/tex]
so:
[tex]F_{c}=m(\frac{4\pi^{2}r}{T^{2}})[/tex]
so now we can do the sum of forces:
[tex]\sum F=ma[/tex]
[tex]F_{g}=ma_{c}[/tex]
[tex]G\frac{Mm}{r^{2}}=m(\frac{4\pi^{2}r}{T^{2}})[/tex]
in this case we can get rid of the mass of the planet, so we get:
[tex]G\frac{M}{r^{2}}=(\frac{4\pi^{2}r}{T^{2}})[/tex]
we can now solve this for [tex]T^{2}[/tex] so we get:
[tex]T^{2} = \frac{4\pi ^{2}r^{3}}{GM}[/tex]
We could take the square root to both sides of the equation but that would not be necessary. Now, the problem tells us that the period of planet 1 is longer than the period of planet 2, so we can build the following inequality:
[tex]T_{1}^{2}>T_{2}^{2}[/tex]
So let's see what's going on there, we'll call:
[tex]M_{1}[/tex]= mass of Star 1
[tex]M_{2}[/tex]= mass of Star 2
So:
[tex]\frac{4\pi^{2}r^{3}}{GM_{1}}>\frac{4\pi^{2}r^{3}}{GM_{2}}[/tex]
we can get rid of all the constants so we end up with:
[tex]\frac{1}{M_{1}}>\frac{1}{M_{2}}[/tex]
and let's flip the inequality, so we get:
[tex]M_{2}>M_{1}[/tex]
This means that for the period of planet 1 to be longer than the period of planet 2, we need the mass of star 2 to be greater than the mass of star 1. This makes sense because the greater the mass of the star is, the greater the force it applies on the planet is. The greater the force, the faster the planet should go so it stays in orbit. The faster the planet moves, the smaller the period is. In this case, planet 2 is moving faster, therefore it's period is shorter.
Sonar is a device that uses reflected sound waves to measure underwater depths. If a sonar signal has a frequency of 288 Hz, and the wavelength is 5.00 m, what is the speed of the sonar signal in water?
Given that,
The frequency of a sonar signal, f = 288 Hz
Wavelength = 5 m
To find,
The speed of the sonar signal in water.
Solution,
Let the speed of the sonar signal is v. The speed in terms of wavelength and frequency is given by :
[tex]v=f\lambda\\\\v=288\times 5\\\\v=1440\ m/s[/tex]
So, the speed of the sonar signal in water is 1440 m/s.
How does the atmosphere affect the hydrosphere?
Answer:
when pure water vapor from the water bodies get absorbed into polluted gases in the atmosphere, acid rain is caused and when this happens in a place where an element of the hydrosphere is located, it is polluted.in such a way hydrosphere is effected
Answer: When a parcel of air in the atmosphere becomes saturated with water, precipitation, such as rain or snow, can fall to Earth's surface.
Explanation:
Human contributions to greenhouse gases in the atmosphere are warming the earth's surface a process which is projected to increase evaporation of surface water and accelerate the hydrologic cycle. In turn, a warmer atmosphere can hold more water vapor.
A brick of gold is 0.1 m wide, 0.1 m high, and 0.2 m long. The density of gold is 19,300 kg/m3. What pressure does the brick exert on the table if the brick is resting on its side?
Answer:
The pressure exerted by the brick on the table is 18,933.3 N/m².
Explanation:
Given;
height of the brick, h = 0.1 m
density of the brick, ρ = 19,300 kg/m³
acceleration due to gravity, g = 9.81 m/s²
The pressure exerted by the brick on the table is calculated as;
P = ρgh
P = (19,300)(9.81)(0.1)
P = 18,933.3 N/m²
Therefore, the pressure exerted by the brick on the table is 18,933.3 N/m².
Which of the following has the most momentum? proton (m=1.67 x 10-27 kg) moving at 2.0 x 104 m/s,an electron (m=9.11 x 10-31 kg) moving at 2.0 x 106 m/s, a common house fly (m=12 mg) moving at 2.0 m/s, North American tectonic plate (m≈5x1022 kg) moving at 3.0x10-10 m/s (about 1cm/yr)
Answer:
The North American tectonic plate.
Explanation:
recall the formula for momentum: p = m * v
the subatomic particles have very small masses while high speeds, so the product results in values with negative exponents in scientific notation.
Negative exponents also result for the house fly when converting mg into kg (10^-6).
The positive exponents in scientific notation for the momentum come for the gigantic mass of the continental plate which exceeds the negative exponents contributed by the small velocity.
Identify the mathematical proportion that relates electrostatic force and displacement for a pair of charged particles.
A. Direct linear
B. Inverse
C. Quadratic
D. Inverse square
Answer:
D. Inverse square
Explanation:
According to the information you are giving me, you must be referring to Coulomb's law because the electrostatic force in proportion to the displacement of charged particles is [tex] F =\frac{kq_{1}q_{2}}{r²} [/tex].
As you can see, there is a reason as to why this is also referred to as Coulomb's inverse square law because the r² represents the displacement or distance relative to the position of the particles which is squared, and it is inverse because the force and the product of the distance squared is equal to the product of the two charges particles multiplied by coulomb's constant (k) which is approximately 8.9875517923×10⁹ kg⋅m³⋅s⁻²⋅C⁻².
The mathematical proportion that relates electrostatic force and displacement for a pair of charged particles is Inverse square. Hence, option (D) is correct.
What is electrostatic force?The electrostatic force is an attractive and repulsive force caused by the electric charges of particles. The electrostatic force is the electric force that exists between two stationary charged bodies. It is also known as Coulomb's force.
Hence, electrostatic force inversely proportional to the distance between two charges. If two charges Q and q are separated by a distance r, the magnitude of electrostatic force between them is given by:
F = kQq/r²
So, the mathematical proportion that relates electrostatic force and displacement for a pair of charged particles is Inverse square. Hence, option (D) is correct.
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What is the voltage across a load that has a resistance of 7.5 ohms and a 1.8 A current flowing through it? *
Answer:
13.5V
Explanation:
u=i*r
u=1.8×7.5=13.5V
A spring is 50 cm in length when not compressed. The spring is then compressed by 35 cm by a force of 100N What is the k value of this spring?
Answer:
k=6.666
Explanation:
F=kx
100=k 50-35
100=k*15
k=6.666
1. The combined forces acting on an object make up the _____ force.
Answer:
If you tethered a space station to the earth by a long cable, you could get to space in an elevator that rides up the cable--much simpler and cheaper than riding to space on a rocket. There's one big problem, however: There is no way to create a cable that is long enough. The cable would need to reach 36,000 km upward, to the height where a satellite orbits at the same speed as the earth rotates; a cable this long made of ordinary materials couldn't even support its own weight. Consider a steel cable suspended from a point high above the earth. The stress in the cable is highest at the top; it must support the weight of cable below it.
What is the greatest length the cable could have without failing? For the purposes of this problem, you can ignore the variation in gravity near the surface of the earth. Hint: The mass of the cable is the volume of the cable multiplied by the density. The density of steel is 7900 kg/m3.
Answer:
[tex]Stress=12903.3923m[/tex]
Explanation:
From the question we are told that
Cable length 36,000km
The density of steel is 7900 kg/m3.
Generally mass is mathematically given as
[tex]m= \rho v[/tex]
[tex]m= \rho Al[/tex]
Generally the weight of cable is mathematically give as
[tex]W_c=mg[/tex]
[tex]W_c=(\rho Al)g[/tex]
Generally the stress on a material is mathematically represented as
[tex]Stress=\frac{Force}{Area}[/tex]
[tex]Stress=\frac{\rho Al}{A}*g[/tex]
[tex]Stress=\frac{\rho l}{1}*g[/tex]
Stress or tensile strength of steel is [tex]1000*10^6N/m^2[/tex]
Therefore
[tex]l=\frac{Stress}{pg}[/tex]
[tex]Stress=\frac{1000*10^6}{(7900)(9.81)}[/tex]
[tex]Stress=12903.3923m[/tex]
[tex]Stress=12903.4m\ appro[/tex]
In class, Kelsey stops paying attention to the lesson and begins to focus on tapping her pencil on her desk. Her teacher slowly walks to Kelsey’s desk and gently takes her pencil from her. How would behaviorist B.F. Skinner MOST likely describe this response?
Answer:
I think it might be negative reinforcement.
Explanation:
Answer:
negative reinforcement
Explanation: