The first scientist misidentified the fossil as that of a big cat. What body structure did he use to make his observations?
A barefoot field-goal kicker imparts a speed of 22 m/s to a football initially at rest. If the football has a mass of 0.42 kg and the time of contact with the ball is 0.023 s, what is the magnitude of the force exerted by the ball on the kicker’s foot? Answer in units of N
Explanation:
Mass of the football = 0.49 kg
Initial velocity of the ball ,u= 0 m/s
Final velocity of the ball ,v= 44 m/s
time of contact ,t = 0.028 seconds
First law of motion:
v=u+at
44 m/s=0+a\times 0.028 sec44m/s=0+a×0.028sec
a=1,571.42 m/s^2a=1,571.42m/s
2
force=mass\times acceleration=0.49 kg\times 1,571.42 m/s^2=769.99Nforce=mass×acceleration=0.49kg×1,571.42m/s
2
=769.99N
The magnitude of the force exerted by the ball on the kicker's foot is of 769.99 Newtons.
What is the resistance at 20°C of a 2.0-meter length of tungsten wire with a cross-sectional area of 7.9 10^-7
meter^2
Answer:
1.4 * 10 ^-1 Ω
Explanation:
Hi,
For this question, we gotta use the formula
R = pL/A
p = The resistivity of your material at 20°C
L = length of the wire
A = cross-sectional area
The resistivity of tungsten is 5.60 * 10^-8 at 20°C
By plugging the values, we get:
R = (5.60 * 10^-8)(2.0)/(7.9*10^-7) = 1.4 * 10 ^-1 Ω
As a warehouse worker pushes a crate across a concrete floor, the force he
applies is not perfectly horizontal, as shown in the image below. If the
coefficient of kinetic friction between the crate and concrete floor is 0.5, what
is the net force on the crate?
Pushing Force
350 N
Weight
460 N
OA. 95 N
OB. 115 N
O C. 130 N
OD. 145 N
10⁰
-Friction Force
2
The crate will be under a net force of 95 N. Resolving the force in the x-direction yields the net force on the crate: F = 300 cos 10° - N F= 295.44-196.45, F= 95.
How do you calculate the frictional force?The resistive force of friction (Fr) divided by the normal or perpendicular force (N) pushing the objects together yields the coefficient of friction (fr), which is a numerical value. The formula fr = Fr/N serves as a representation of it.
What are the friction laws?The friction of a moving item is inversely proportional to the normal force and runs perpendicular to it. The type of surface the thing comes into touch with determines the amount of friction it experiences. As long as there is a point of contact, friction does not depend on the area of contact.
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A 30-N iPad is dropped from a height of 10 m and strikes the ground with a speed of 13 m/s.
What average force of air friction acted on the iPad as it fell?
Answer:
Initially the PE of the object was W * h = 30 * 10 = 300 Joules
The KE of the object when it struck the ground was 1/2 M v^2
KE = 1/2 * 30/9.8 * 13^2 = 259 J
So the object lost 41 J to friction during the fall
Since Work = Force * distance
Force = 41 J / 10 m = 4.1 N (the average force of friction)
1. Which statement about data attenuation is true? (1 point)
Data carried on a fiber-optic cable experience more attenuation than data broadcast from a radio tower.
Fiber-optic cables experience very little attenuation over large distances.
Data carried on a fiber-optic cable experience more attenuation than data carried on a copper wire.
Data carried on a copper wire and data broadcast from a radio tower experience very little attenuation over large distances.
2. Which statement is an example of information being carried by an electromagnetic wave that has been interpreted by humans?(1 point)
A sound wave in an ultrasound machine transmits information about the parts of the body it travels through.
A seismic wave changes speed, conveying information about the materials it has passed through.
A wave in the ocean changes, indicating a change in the depth of the water.
A light wave from a distant galaxy experiences redshift, indicating that the galaxy is moving away from Earth.
3. Which statement is true about a parabolic dish? (1 point)
It reflects waves and focuses them to a point.
It refracts waves in the dish.
It absorbs the wave energy.
It filters the type of electromagnetic radiation.
4. Which natural phenomenon describes guitar strings vibrating at certain natural frequencies?(1 point)
interference
beats
oscillation
resonance
5. What will increase the power output when doing work?(1 point)
doing less work in the same amount of time
doing the same work in less time
doing the same work in more time
doing less work and increasing the amount of time
Answer:
1. c
2. d
3. a
4. d
5. c
Explanation:
im pretty sure im right
A student collected data about the speed of an object over time.
Which type of graph should the student use to represent the data?
Answer:I have already did this the answer was bar graph!
Explanation:
How many times does the kinetic energy of a car increase when traveling 60 mph as opposed to traveling 15 mph?
K.E. increases
5
4
16
20
Answer:
20
Explanation:
i'm not so sure with my answer
The four conducting cylinders shown in the figure are all made of the same material, though they differ in length and/or diameter. They are connected to four different batteries, which supply the necessary voltages to give the circuits the same current, I.
Rank the four voltages. V₁, V₂, V₃, and V₄. in order of decreasing value. Rank from largest to smallest. To rank items as equivalent, overlap them.
This content in not available an your mobile device, but your work is still incomplete. Please use a different device to submit your solution for grading
The ranking of the voltages, V₁, V₂, V₃, and V₄ in the order of decreasing voltage value is; V₂ > V₃ > V₁ > V₄
What is the voltage of an electric circuit?A voltage is the difference in potential or pressure that pushes or causes the flow of electric current in a circuit or conducting loop.
The current flowing through the circuit can be found using the following formula;
[tex]I=\dfrac{V}{R}[/tex]
The formula for conductivity is presented as follows;
[tex]\sigma =\dfrac{l}{R\times A}[/tex]
Where;
σ = The conductivity of the material
l = The length
R = The resistance to electricity
A = The cross-sectional area of the conductor
Therefore;
[tex]R=\dfrac{V}{I}[/tex]
[tex]R=\dfrac{l}{A\times \sigma}[/tex]
[tex]\dfrac{V}{I} =\dfrac{l}{A\times \sigma}[/tex]
[tex]V=\dfrac{l \times I}{A\times \sigma}[/tex]
Based on the dimensions of the cylinders, obtained from a similar question, we get;
[tex]V_1=\dfrac{3\cdot L \times I}{\pi \cdot D^2\times \sigma} = 3\times \dfrac{ L \times I}{\pi \cdot D^2\times \sigma}[/tex]
[tex]V_2= \dfrac{2\cdot L \times I}{\pi \cdot \dfrac{D^2}{4} \times \sigma} = \dfrac{8\cdot L \times I}{\pi \cdot D^2\times \sigma} = 8\times \dfrac{ L \times I}{\pi \cdot D^2\times \sigma}[/tex]
[tex]V_3=\dfrac{L \times I}{\pi \cdot \dfrac{D^2}{4} \times \sigma} =\dfrac{4\cdot L \times I}{\pi \cdot D^2\times \sigma}= 4\times \dfrac{L \times I}{\pi \cdot D^2\times \sigma}[/tex]
[tex]V_4=\dfrac{L \times I}{\pi \cdot D^2\times \sigma} = 1\times \dfrac{ L \times I}{\pi \cdot D^2\times \sigma}[/tex]
Therefore;
V₁ = 3·V₄
V₂ = 8·V₄
V₃ = 4·V₄
The rank of the voltages in the order of decreasing value is therefore;
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Find the Input force, if the Mechanical Advantage of the simple machine used is 5 and Output force is 50 N.
P.S PLEASE DO NOT POST A LINK THAT I HAVE TO DOWNLOAD EVERY TIME I ASK A QUESTION PEOPLE POST THAT JUST POST A WRITEN ANSWER WITH AN EXPLINATION THAT IS ALL
Answer:
6N
Explanation:
5. The picture shows a mass that is attached to a spring with constant, K = 500 N/m(20 points)
The mass is of 2 kg and the values of the heights are:h1= 5 meters,h2= 10 meters andh3= 2 meters.•The spring is compressed a length of 80 cm.
What is the speed of the mass when it reaches a height of h2?
•What is the speed of the mass when it reaches a heighth3?
Answer:
[tex]\text{(a)}\\\text{Given that current energy at starting point }h_{1} \text{ is}:\\E_{h1}=mgh+\frac{1}{2}kx^2\\\text{Plug in height and mass: }E_{h1}=10g+250(0.8)^2=10g+160=258J\\\text{Using Conservation of Energy: }E_{h1}=E_{h2} \\\therefore 258J=mg(h_{2}-h_{1})+\frac{1}{2}mv^2\\=258J=10g+v^2\\=160=v^2\\\therefore v=40m/s \text{ at }h_{2}\\[/tex][tex]\text{(b)}\\\text{Again, apply conservation of energy: } 258J=mg(h_{3}-h_{2})+\frac{1}{2}mv^2\\\text{Plugging in: }258J=16g+v^2 \\\text{ Simplify: }101.2=v^2\\\therefore v=10.05m/s \text{ at } h_{3}[/tex]
A certain string can withstand a maximum tension of 55N before breaking.What is the maximum speed at which we can safely swing a 1.0 kg mass on a piece of this string 0.50m long in a horizontal circle?
Explanation:
Fmax = Fc = mv^2/r
[tex]m \frac{ {v}^{2} }{r} = f\frac{}{max} \\ {v}^{2} = \frac{(0.50 \: m)(55 \: n)}{1.0 \: kg} = 27.5 \: \frac{ {m}^{2} }{ {s}^{2} } \\ v = 5.2 \: \frac{m}{s} [/tex]
You have a Coke bottle with an air cavity
that is 0.220 m deep. You add water to
the bottle, shortening the column, so
that when you blow across the top, it
plays a 528 Hz fundamental. How tall is
the water column in the bottle?
Answer: 0.0576
Explanation:
The equation for fundamental frequency for closed pipes is as follows:
f(1) = v/4L
In which v is the speed of sound (343 m/s) and L is the length of the pipe. Therefore:
528 = 343/4L
x = 0.1624
This is not the answer as you still need to subtract it from the original length.
0.220 - 0.1624 = 0.0576
A cyclist intends to cycle up an 8 degrees hill whose vertical height is 150 m, with constant speed. If each complete revolution of the pedals moves the bike 6 m along its path, calculate the average force that must be exerted on the pedals tangent to their circular path. Neglect work done by friction and other losses. The pedals turn in a circle of diameter D = 30 cm. The total mass of the cyclist and his bike is 150 kg.
Answer: [tex]1302.25\ N[/tex]
Explanation:
Given
Inclination of hill [tex]\theta=8^{\circ}[/tex]
Each revolution moves 6 m along its path
Diameter of the circle [tex]D=30\ cm[/tex]
the total mass of the cyclist and his bike [tex]M=150\ kg[/tex]
Suppose a single pedal cyclist gain a vertical height of [tex]\Delta y[/tex]
[tex]\therefore \sin \theta =\dfrac{\Delta y}{6}\\\\\Delta y=6\sin 8^{\circ}[/tex]
Average force cause to gain in Potential energy
[tex]\therefore\ F_{avg}\cdot 2\pi r=Mg\Delta y\\\Rightarrow F_{avg}=\dfrac{150\times 9.8\times 6\sin 8^{\circ}}{2\pi\cdot 0.15}\\\\\Rightarrow F_{avg}=1302.25\ N[/tex]
Thus, the average force is [tex]1302.25\ N[/tex]
Which of the following best explains the cause and effect relationship between convection currents in the mantle and the movement of tectonic plates?
A. The tectonic plates will heat up the mantle due to being closer to the surface of the earth and sun. The less dense particles in the mantle fall and cool toward the core, driving the convection cycle.
B. The tectonic plates drive the convection cycles in the mantle. As the plates move apart or push together, particles in the mantle will be thrust toward the core.
C. The heat from the core will make the particles in the mantle more dense and rise, causing plates in the
lithosphere to move in the opposite direction of the convection current.
D. The heat from the core will make particles in the mantle less dense and rise, causing plates in the
lithosphere to move in the direction of the convection current.
C) The mantle's particles will become more dense and rise as a result of the core heat, causing the lithosphere's plates to move in the opposite direction of the convection current.
How does the mantle's density change as it heats up?Convection Currents The lithosphere becomes denser than the surrounding magma and sinks back toward the core as the heated mantle transfers heat energy to it.
How does heat travel from the core to the crust in the mantle?Conduction from the core directly heats the lower mantle. As atoms collide, heat is transferred in conduction. Convection is the movement of warm and cool materials upward and downward. Material that is hot rises to the surface through conduction.
When the mantle rises, what takes place?“hot spots," which are non-plate tectonic volcanic regions, are probably caused by mantle plumes. A diapir is formed when a mantle plume reaches the upper mantle. Volcanic eruptions are sparked by the heat generated by this molten material in the asthenosphere and lithosphere.
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what electrical devices that belong to physiological effect?
Answer:
Most of us have experienced some form of electric “shock,” where electricity causes our body to experience pain or trauma. If we are fortunate, the extent of that experience is limited to tingles or jolts of pain from static electricity buildup discharging through our bodies.
When we are working around electric circuits capable of delivering high power to loads, electric shock becomes a much more serious issue, and pain is the least significant result of shock.
As electric current is conducted through a material, any opposition to the current (resistance) results in a dissipation of energy, usually in the form of heat. This is the most basic and easy-to-understand effect of electricity on living tissue: current makes it heat up. If the amount of heat generated is sufficient, the tissue may be burnt.
The effect is physiologically the same as damage caused by an open flame or other high-temperature source of heat, except that electricity has the ability to burn tissue well beneath the skin of a victim, even burning internal organs.
A 500-mm-long, 16-mm-diameter rod made of a homogenous,
isotropic material is observed to increase in length by 300 mm, and
to decrease in diameter by 2.4 mm when subjected to an axial 12-
kN load. Determine the modulus of elasticity and Poisson's ratio of
the material. [20 marks]
The material has a Poisson's ratio and a modulus of elasticity of 0.25. Y=2G(1+) is the correct relationship between the Young's modulus (Y), the shear modulus (G), and the Poisson's ratio ().
What are elastic modulus and Poisson's ratio?The bulk modulus, also known as the elastic modulus K, is related to the Poisson's ratio; G as the modulus of shear; and E, Young's modulus, by the following (for isotropic solids whose properties are non-directional). The stiffness is measured by the elastic moduli. They are stress-to-strain ratios.
Determine the rod's stress level.
Determine the longitudinal strain by multiplying F A 12 by (0.016) = 59.683 MPa.
Determine the lateral strain by elongating Or 30010-3 = L mm 500 mm = = 0.0006.
-2.410-3 mm 16 mm Elateral = = -0.00015 d Determine the material's young's modulus.
& Long 59.683 MPa 0.0006 E = 99.471 GPa 100 GPa
Determine the material's poisson's ratio. & the lateral lengthens by -0.00015 0.0006 = 0.25.
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Both formal and informal
Explanation:
is this a question????...
an object is 50 cm to the left and an image is 50 cm to the right of a convex lens. What is the focal length?
Answer:
An Object son
Explanation:
Q8. An alluminum object has
a mass of 27.0 Kg and a dan
[sity of 2.70x10² Kgm–³ The object
is attached to a string and
immersed in a tank of water . determine the volume of the object and the tension force
Answer:
volume=0.1m^3 and force=270N
Explanation:
Solution
Given,
mass=27kg
density=2.70×10^2=270kg/m^3
volume =?
force=?
We have,
force=m×a=27×10=270N
density =m÷v
v×d=m
v=m÷d
=27÷270
=0.1m^3
d. The mass of the boy is the same in all places because mass does not depend
on gravity.
True or False
(Science)
Explanation:
Remember, even if you weigh less because of a change in gravity's force on your body, your body's mass is still the same. As your body grows, you will have more mass, which also means you will weigh more. That's because when you're on the earth, the amount of gravity that pulls on you stays the same.Thank you for marking me Brainlist ☺️Answer:
true . it depends tho weight depends on gravity .
please help AFAP........................
Answer:
afap
Explanation:
6. One light bulb in the kitchen
burns out and suddenly several
lights go out in the house. This
would provide evidence that the
bulbs were wired in -
series
Parallel
Reverse
Different circuits
Answer:
Series
Explanation:
If all your lightbulbs are on the same circuit and one blows out then that means your circuit has been broken and the rest won't work.
When a light bulb in the kitchen burns out, numerous lights in the home go off at once. This would provide evidence that the bulbs were wired in series.
What is series circuit?In the series circuit, the amount of current flowing through any component in a series circuit is the same and the sum of the individual resistances equals the overall resistance of any series circuit.
The voltage in a series circuit, the supply voltage, is equal to the total of the individual voltage drops.
When one bulb in a series circuit burns, out, the rest of the bulbs stop shining and shut off.
When a light bulb in the kitchen burns out, numerous lights in the home go off at once. This would provide evidence that the bulbs were wired in series.
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What is kinetic energy
Answer:
Kinetic Energy
Explanation:
Kinetic energy is the energy of motion, observable as the movement of an object, particle, or set of particles
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Which of the following describes a negative ion?
Two students are balancing on a 10m seesaw. The seesaw is designed so that each side of the seesaw is 5m long. The student on the left weighs 60kg and is sitting three meters away from the fulcrum at the center. The student on the right weighs 45kg. The seesaw is parallel to the ground. The mass of the board is evenly distributed so that its center of mass is over the fulcrum. What distance from the center should the student on the right be if they want the seesaw to stay parallel to the ground?
a. 4m
b. 5m
c. 2m
d. 3m
NO LINKS.
Answer:
B.5m
Explanation:
not sure if i'm right;)
A plane electromagnetic wave propagates in a vacuum in the z-direction. The wave has a wavelength of 10 m and the electric field is along the x direction and has an amplitude of is 0.20 V/m, with one maximum at x = 0 and t = 0. What is the mathematical expression for the magnetic field?
A. By = 0.067 × 10-8sin[(0.63 m-1)z - (2.1 × 10-9 s-1)t] T.
B. By = 0.067 × 10-8cos[(0.63 m-1)z + (1.9 × 108 s-1)t] T.
C. By = 0.067 × 10-8cos[(10 m-1)z - (2.1 × 10-9 s-1)t] T.
D. By = 0.067 × 10-8cos[(0.63 m-1)z - (1.9 × 10-8 s-1)t] T.
E. By = 0.067 × 10-8sin[(0.63 m-1)z + (2.1 × 10-9 s-1)t] T.
Answer:
B. By = 0.067 × 10-8cos[(0.63 m-1)z + (1.9 × 108 s-1)t] T.
Explanation:
Since the electric field has a maximum at x = 0 and t = 0, it is a cosine function and thus the magnetic field is also a cosine function.
Also, the electric field travels in the x - direction and the wave in the z-direction. Since the magnetic field is perpendicular to both directions, it must thus move in the y - direction.
So, By = B₀cos(kz - ωt). It has a negative sign since the wave is travelling in the positive z - direction.
Since c = E₀/B₀ where E₀ = amplitude of electric field = 0.20 V/m, B₀ = amplitude of magnetic field and c = speed of light = 3 × 10⁸ m/s
So, B₀ = E₀/c = 0.20 V/m ÷ 3 × 10⁸ m/s = 0.067 × 10⁻⁸ T
wave number, k = 2π/λ where λ = wavelength = 10 m. So, k = 2π/10 m = 6.28/10 m = 0.628 m⁻¹ ≅ 0.63 m⁻¹
angular frequency, ω = 2πf where f = frequency of wave = c/λ = 3 × 10⁸ m/s 10 m = 3 × 10⁷ s⁻¹. So, ω = 2πf = 2π(3 × 10⁷ s⁻¹) = 18.8 × 10⁷ s⁻¹ = 1.88 × 10⁸ s⁻¹ ≅ 1.9 × 10⁸ s⁻¹
Substituting the variables into By, we have
By = B₀cos(kz - ωt)
By = (0.067 × 10⁻⁸ T)cos[(0.63 m⁻¹)z - (1.9 × 10⁸ s⁻¹)t]
By = 0.067 × 10⁻⁸cos[(0.63 m⁻¹)z - (1.9 × 10⁸ s⁻¹)t] T
Since none of our options contain the given answer, we assume the wave moves in the negative z - direction. So, for that,
By = 0.067 × 10⁻⁸cos[(0.63 m⁻¹)z + (1.9 × 10⁸ s⁻¹)t] T
Answer:
D.
[tex]\mathbf{B_y = 0.067 \times 10^{-8} Cos \Big[ 0.6 3m^{-1} z - (1.9 \times 10^{-6} \ s^{-1})t \Big] T}[/tex]
Explanation:
From the given information:
Let us recall that the direction with which electromagnetic wave proceeds is usually along [tex]E^{ \to} \times B^{\to}[/tex]
Thus; the magnetic field is always along the y-direction.
In the magnetic field, the maximum value of the field is expressed by using the formula:
[tex]\dfrac{E}{C} = \dfrac{0.20 \ V/m}{3\times 110^8 \ m/s} \\ \\ = 0.067 \times 10^{-8} \ T[/tex]
Given that:
the maximum x is starting at 0, then, it implies that it is starting from the extreme position proceeding along +z direction.
As such; the general equation: [tex]y = A sin (\omega t - kz)[/tex]
Also:
[tex]K = \dfrac{2 \pi}{\lambda}[/tex]
where;
[tex]\lambda =10[/tex]
[tex]K = \dfrac{2 \pi}{10}[/tex]
K ≅ 0.63 m⁻¹
Thus;
[tex]\mathbf{B_y = 0.067 \times 10^{-8} Cos \Big[ 0.6 3m^{-1} z - (1.9 \times 10^{-6} \ s^{-1})t \Big] T}[/tex]
whats it like to be famous?
Good And Bad
Explanation:
People often want to be famous to be recognized in public or even to meet other famous people.
however what people dont realise is that you life is now entirely public, your love life, relationships, the food you eat, the people you talk to,the way you act ,ect Everything is publicly judged.
yes it may be good to be famous for some reasons however, 9 times out of 10 it may be the worst part of your life.
Those in mission control roles spend about 75 percent of their time actively communicating and controlling active space missions.
True
False
It is False that personnel in mission control spend roughly 75% of their time actively engaging with and managing running space missions, according to the evidence at hand.
What is Mission control centre?The NASA Johnson Space Center has a designated center called Mission Control Center.
Only 10% of the time that the MCC staff devotes to mission control is actually spent actually managing missions; the other 80% is spent planning and organizing, and the remaining 15% is spent on training and education.
A facility that oversees space flights is known as a mission control center (MCC; sometimes known as a flight control center or operations center), often from the point of launch until landing or the mission's conclusion. It is a component of spacecraft operations on the ground.
Therefore, It is False that personnel in mission control spend roughly 75% of their time actively engaging with and managing running space missions, according to the evidence at hand.
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Question 5 of 15:
Select the best answer for the question
5. Eighteen cubic feet of air having a pressure of 60 psia and a temperature of 190 F is to be compressed, together with 28 cu ft of air having a pressure of 40 psia and a temperature
of 60 F, in a vessel whose volume is 22 cu ft. What will be the temperature of the mixture, if its pressure is 100 psia?
7
O A. 370 F
O B. 577 F
O C. 117 F
O D. 90 F
90 F. The temperature of the mixture can be calculated using the Ideal Gas Law.
This states that the product of the pressure, volume, and absolute temperature of a gas is equal to the product of the number of moles of the gas and the universal gas constant.
Using this equation, we can solve for the temperature of the mixture, given the total pressure and the total volume of the mixture.
We can first calculate the total number of moles of the mixture, by assuming both gases are ideal:
18 cu ft of gas at 60 psia and 190 F = 1.64 moles
28 cu ft of gas at 40 psia and 60 F = 1.28 moles
Total moles of the mixture = 2.92 moles
Using the Ideal Gas Law, we can then calculate the temperature of the mixture:
(100 psia x 22 cu ft x T) = (2.92 moles x 0.082)
T = 90 F.
What is the Ideal Gas Law?
The Ideal Gas Law is an equation that describes the relationship between pressure, volume, temperature, and amount (in moles) of an ideal gas. It states that: PV = nRT, where P is the pressure, V is the volume, n is the amount of substance, R is the ideal gas constant, and T is the temperature.
Hence, Option D is correct.
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