Let the upstream breadcrumb's position act as the origin, so the position at time [tex]t[/tex] of upstream crumb [tex](B_U)[/tex], duck [tex](D)[/tex], and downstream crumb [tex](B_D)[/tex] are, respectively,
[tex]x_{B_U} = \left(2.0\dfrac{\rm m}{\rm s}\right) t[/tex]
[tex]x_D = d\,\mathrm m + v_D t[/tex]
[tex]x_{B_D} = 2d\,\mathrm m + \left(2.0\dfrac{\rm m}{\rm s}\right) t[/tex]
where [tex]d[/tex] is the distance (in m) between the duck and either crumb at the start, and [tex]v_D[/tex] is the velocity of the duck relative to the Earth.
To get both breadcrumbs, the duck has to choose between chasing the upstream or downstream crumb first.
• If the upstream crumb is chosen first, then [tex]v_D[/tex] is 2.0 - 1.0 = 1.0 m/s. Find the time it takes for the duck to reach the upstream crumb:
[tex]x_{B_U} = x_D \implies \left(2.0\dfrac{\rm m}{\rm s}\right) t = d + \left(1.0\dfrac{\rm m}{\rm s}\right) t \\\\ \implies t = d \, \mathrm s[/tex]
In this time, the duck covers a distance of
[tex]x_D = d\,\mathrm m + \left(1.0\dfrac{\rm m}{\rm s}\right) (d\, \mathrm s) = 2d \, \mathrm m[/tex]
while the downstream crumb will have traveled a distance of
[tex]x_{B_D} = 2d\,\mathrm m + \left(2.0\dfrac{\rm m}{\rm s}\right) (d \,\mathrm s) = 4d \,\mathrm m[/tex]
putting a total distance of [tex]2d+4d=6d\,\mathrm m[/tex] between the duck and the remaining crumb.
Take the duck's new position to be the new origin. When the duck turns around and travels with the current, its speed [tex]v_D[/tex] will be 2.0 + 1.0 = 3.0 m/s. Then at time [tex]t[/tex], the duck and remaining crumb have position relative to the new origin given by
[tex]x_D' = \left(3.0\dfrac{\rm m}{\rm s}\right) t[/tex]
[tex]x_{B_D}' = 6d \,\mathrm m + \left(2.0\dfrac{\rm m}{\rm s}\right) t[/tex]
Find the time the duck needs to catch up to the downstream crumb:
[tex]x_D' = x_{B_D}' \implies \left(3.0\dfrac{\rm m}{\rm s}\right) t = 6d\,\mathrm m + \left(2.0\dfrac{\rm m}{\rm s}\right) t \\\\ \implies t = 6d \,\mathrm s[/tex]
Then the total time the duck needs to get both crumbs is [tex]d + 6d = 7d \,\mathrm s[/tex].
• If instead the downstream crumb is chased down first, we start with [tex]v_D[/tex] = 3.0 m/s, so that
[tex]x_D = x_{B_D} \implies d\,\mathrm m + \left(3.0\dfrac{\rm m}{\rm s}\right) t = 2d\,\mathrm m + \left(2.0\dfrac{\rm m}{\rm s}\right) t \\\\ \implies t = d \, \mathrm s[/tex]
In this time, the duck covers a distance of
[tex]x_D = d\,\mathrm m + \left(3.0\dfrac{\rm m}{\rm s}\right) (d\,\mathrm s) = 4d \,\mathrm m[/tex]
while the upstream crumb moves
[tex]x_{B_U} = \left(2.0\dfrac{\rm m}{\rm s}\right) (d\,\mathrm s) = 2d \,\mathrm m[/tex]
The distance between the duck and remaining crumb is then [tex]4d-2d=2d\,\mathrm m[/tex]. Now the duck turns around with speed [tex]v_D[/tex] = 1.0 m/s. If the crumb's new position is taken to be the origin, then
[tex]x_{B_U}' = \left(2.0\dfrac{\rm m}{\rm s}\right) t[/tex]
[tex]x_D' = 2d\,\mathrm m + \left(1.0\dfrac{\rm m}{\rm s}\right) t[/tex]
Find the time it takes for the duck to get the last crumb:
[tex]x_{B_U}' = x_D' \implies \left(2.0\dfrac{\rm m}{\rm s}\right)t = 2d\,\mathrm m + \left(1.0\dfrac{\rm m}{\rm s}\right) t \\\\ \implies t = 2d\,\mathrm s[/tex]
Then the duck can get both crumbs in a total of [tex]d+2d=3d\,\mathrm s[/tex].
To get both crumbs in the shortest time, the duck should go after the downstream crumb first. This path over 2 times faster than the other.
A series circuit consists of a switch, a 6-v battery, a lightbulb, and some copper wire. Whenever the circuit is turned on, each of these elements has the same
Whenever the circuit is turned on, each of these elements has the same current through it. The correct option is A.
The current is stream of charges flowing through circuit from the positive terminal to the negative terminal of the voltage source.
A series circuit consists of a switch, a 6-v battery, a lightbulb, and some copper wire. The circuit has the current I flowing in it. Light bulb will act as resistor. When the circuit is on, current will flow through the entire circuit and its elements starting from the positive terminal of battery to the negative terminal of battery.
Thus, whenever the circuit is turned on, each of these elements has the same current through it. The correct option is A.
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Mass of an object is 45 kg. What is its weight on the earth?(g=9.8m/s2)
[tex]\text{Weight,}~ \\\\W = mg = 45 \times 9.8 = 441~ N\\\\\text{The weight of the object on earth is 441 N}.[/tex]
The diagram shows a system in which a collision occurs between two toy cars.
What is the decrease in kinetic energy during the collision?
(A) -63 J
(B) -1.4 J
(C) -1.1 J
(D) -0.17 J
The decrease in kinetic energy during collision is 0.171 joule. Hence, option (D) is correct.
What is kinetic energy?The energy an object has as a result of motion is known as kinetic energy in physics. It is described as the effort required to move a mass-determined body from rest to the indicated velocity.
The body holds onto the kinetic energy it acquired during its acceleration until its speed changes. The body exerts the same amount of effort when slowing down from its current pace to a condition of rest.
Hence, the decrease in kinetic energy during collision =
Total initial kinetic energy - total final kinetic energy
= {1/2 × 1.15 ×(1.05)² + 1/2 ×2.25 × 0² - (1/2 × 1.15 × 0.13² + 1/2 ×1.25 × 0.85²)} Joule
= { 0.633 + 0 - 0.010 - 0.452} joule
= 0.171 joule.
Hence, The decrease in kinetic energy during collision is 0.171 joule.
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Gravitation always does negative work. question 48 options: true false
The statement indicating that 'Gravitation always does negative work' is FALSE.
What is Gravitation?Gravitation is a fundamental physical force that makes objects attract each other in the Universe.
This force (Gravitation) is required to maintain both constant positions and movement of objects.
In conclusion, the statement indicating that 'Gravitation always does negative work' is FALSE.
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Answer:false
Explanation:
L 6.3.2 Test (CST): Applications of Waves Question 5 of 10 Which event provides evidence that matter can reflect waves? O A. An audience member covers her ears during a loud concert. B. A laser beam bounces off a series of mirrors. C. A performer makes shadow puppets on a wall. D. The light from a fireworks show is seen miles away.
An audience member covers her ears during a loud concert shows evidence that matter can reflect waves.
Which event provides evidence that matter can reflect waves?An audience member covers her ears during a loud concert is an event that provides evidence that matter can reflect waves because a sound is heard again and again due to the reflection of waves. This repetition of sound is due to the property of reflection of sound waves.
So we can conclude that an audience member covers her ears during a loud concert shows evidence that matter can reflect waves.
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Answer:
A laser beam bounces off a series of mirrors
Explanation:
Does the amount of fuel depend on how fast water heats?
Answer:
yes
Explanation:
because when the water is heating up you use more fuel than you do when it is cold
Was this a chemical reaction? Did new products form? Make the choice that answers those questions:
The procedure is not found here but a chemical reaction is characterized to be a process where substances are converted into products.
What is a chemical reaction?A chemical reaction is a process where one or more reactants are converted into chemical products.
In a chemical reaction, enzymes are molecules that speed up the process by lowering its activation energy.
In conclusion, the procedure is not found here but a chemical reaction is characterized to be a process where substances are converted into products.
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Which of the following desribes a displacement vs. time graph that looks like
this?
Time
A. constant non-zero acceleration
B. increasing velocity
C. constant velocity
D. decreasing acceleration
Why is it making me do this
Answer:
I don't know.
Explanation:
I have no idea what you are referring to.
In a belly-flop diving contest, the winner is the diver who makes the biggest splash upon hitting the water. the size
of the splash depends not only on the diver's style, but also on the amount of kinetic energy the diver has. consider
a contest in which each diver jumps from a 3.00-m platform. one diver has a mass of 136 kg and simply steps off
the platform. another diver has a mass of 100 kg and leaps upward from the platform. how high would the second
diver have to leap to make a competitive splash?
The second diver have to leap to make a competitive splash by 4.08 m high.
What is potential energy?The energy by virtue of its position is called the potential energy.
PE = mgh
where, g = 9.81 m/s²
Given is the diver jumps from a 3.00-m platform. one diver has a mass of 136 kg and simply steps off the platform. another diver has a mass of 100 kg and leaps upward from the platform.
The potential energy of the first diver must be equal to the second diver.
P.E₁ = P.E₂
m₁gh₁ = m₂gh₂
Substitute the vales, we have
136 x 3 = 100 x h₂
h₂ = ₂4.08 m
Thus, the second diver need to leap by 4.08 m high.
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These waves are needed for green plants to grow.
-microwaves
-X-rays
-infrared
-ultraviolet
-radio
-visible
-gamma rays
Answer:
visible waves are needed for green plants to grow.
Explanation:
During photosynthesis, chlorophyll absorbs energy from blue- and red-light waves, and reflects green-light waves, making the plant appear green.
A student drew the following flowchart.
Crushing > Sizing > Concentrating > Dewatering
What is the purpose of the process?
A. To refine crude oil
© B. To precipitate minerals
O C. To refine minerals
O D. To blend coal
To refine minerals best describes the purpose of the process mentioned and is denoted as option B.
What is Refining?
Thi involves the different processes involved in the purification of the elements found in the earth.
Refining materials usually starts with crushing and ends with dewatering to drain water.
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A 2000-kg ore car rolls 50 meters down a smooth 10o incline. There is a horizontal spring at the end of the incline designed to stop the car in case of break failure. What is the spring constant of the spring if it would compress by 1 m to stop the ore car?
The spring constant of the spring if it would compress by 1 m to stop the ore car is 340,350.4 N/m.
Potential energy of the carThe potential energy of the car is calculated as follows;
P.E = mgh
where;
h is the vertical height of the inclinesin (10) = h/L
h = L x sin(10)
P.E = mgLsin(10)
P.E = 2000 x 9.8 x 50 x sin(10)
P.E = 170,175.21
Conservation of energyThe potential energy of the car at the top of the incline will be converted to the elastic potential energy spring at the bottom of the incline.
P.E = U = ¹/₂kx²
k = (2U)/x²
k = (2 x 170,175.2)/(1)²
k = 340,350.4 N/m
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5.
A device known as the nMRI, or nuclear magnetic resonance imager, often called an MRI for simplicity, is used for what purpose?
A to generate electricity
B to apply lasers to precision measurements of the nucleus
C to create an image of objects inside other objects
D to measure geologic pressures deep underground in volcanically active regions
Answer:
C. to apply lasers to precision measurements of the nucleus
Explanation:
Magnetic resonance imaging (MRI) is based on the principles of nuclear magnetic resonance (NMR), a spectroscopic technique used to obtain microscopic chemical and physical information about molecules.
An inventor claims to have invented a perpetual motion machine, a machine that creates its own power and energy
allowing it to run forever. Which of the following laws best explains why this invention cannot be true?
A
the law of conservation of matter
B
the law of conservation of energy
C
newtons 3rd law
D
newtons 2nd law
Answer:
B. The law of conservation of energy
Explanation:
The law of conservation of energy states that energy can neither be created or destroyed which means that a perpetual motion machine, which creates its own power and energy, cannot be true since energy cannot be created.
what is the triboelectric effect?
Answer:
The triboelectric effect is an electrical phenomenon where certain materials become electrically charged after coming into contact with another, different, material. The polarity and strength of the charges produced differ according to material and surface smoothness.
Explanation:
The triboelectric effect causes an electrostatic charge to build up on the fur due to the cat's motions. The electric field of the charges results in a slight attraction of the light plastic pieces to the charged fur. The triboelectric effect is also the cause of static cling in clothes.
I hope this helps, if it doesn't then just message me and ill be more than happy to help :)
A forces of 5 N accelerates an object. The object’s mass is 50 g. What is the acceleration of the object? (Formula: F=ma)
Answer:
100 m / s^
F =ma from this divided F and ma by m to get acceleration
a = F / m
a = ?
F = 5 N
m = 50 g = 0. 0 5 kg ; if 1 kg = 1000g how much kg of 50 g by criss cross method we get 0.05 kg
so; 5N / 0. 05 kg = 5kg m / s^ / 0.05 kg
kg cancel by kg
the result is 100 m/ s^
If i apply mascara on a roller coaster, will my eyelashes fly off or get ruined?
0.2 kg coffee cup is sitting on desk. acceleration due to gravity is 9.8m/s^2 what is the force downward exerted
[tex]~~~~~~~F = mg\\\\\implies F = 0.2 \times 9.8\\\\\implies F = 1.96~N\\\\\text{The downward force is 1.96 N.}[/tex]
Which of these is true about analog signals?
1. They can capture the entire sound wave when a song is recorded on a vinyl record, resulting in a Fuller and more accurate representation of the original song.
2. A vinyl record (analog) can hold more information than a CD (digital)
3. The sound quality does not degrade when copying a vinyl record (analog) like it does for CD (digital)
PLEASE HELP LOL, I NEED TO SUBMIT THIS BEFOFE MY SCHOOL YEAR ENDS -_-
The statement true about the analog signal is they can capture the entire sound wave when a song is recorded on a vinyl record, resulting in a Fuller and more accurate representation of the original song.
What are analog signals?The analog signals are discrete in nature.
Sound can be recorded, stored and played by the use of either digital or analog techniques.
Vinyl records produces a continuous sound wave vs CDs. So, analog is more accurate,
Thus, correct option is 1.
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A 2.0-ohm resistor and a 4.0-ohm resistor are connected in series with a 12-volt battery. If the current through the 2.0-ohm resistor is 2.0 amperes, the current through the 4.0-ohm resistor is
Answer:
2.0 A
Explanation:
Current through series-connected components is the same.
__
If the components are connected in series, and the current through one of them is 2.0A, then the current through the other is also 2.0A.
The current through the 4.0 Ω resistor is 2.0 A.
Determine the safest option in the lab if you need your vision to be corrected. select one: wear safety goggles without any corrective lenses for the whole experiment wear safety goggles while working and switch to corrective glasses when you need to read something wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your ta or instructor for your school's policy wear your corrective glasses or lenses as normal for the whole experiment
The safest option in the lab if one need your vision to be corrected is wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your ta or instructor for your school's policy.
What are safety goggles?When someone is performing any project in the chemistry lab, he needs to be extra care taken by himself and and the most importantly from the school. The safety goggles are used to protect the eyes from any spiling off the chemical.
One should wear corrective glasses under the safety goggles during the whole experiment.
Thus, wear corrective glasses under the safety goggles during the whole experiment.
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True or false: Scientific models are always built to scale, and are fully functional representations of the product they are testing.
Answer:
False
Explanation:
Scientific models are not always built to scale and may not be fully accurate
Which image best represents kinetic energy?
Answer:
throwing a ball
Explanation:
because when we throw the ball we apply force so that the ball goes faster
What is the ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2
The ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2 will be the ratio of the angular velocity.
What are comets ?Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices.
It should be noted that the tangential speed can alternatively be represented as;
[tex]\rm v_t= r\frac{d\theta}{dt}[/tex]
where,
θ is the comet's position angle with respect to some given direction.
The amount dθ/dt is known as angular speed
The ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2 IS;
[tex]\rm \frac{v_1}{v_2} = \frac{\frac{d \theta_1}{dt_1} }{\frac{d \theta_2}{dt_2} } \\\\\ \frac{v_1}{v_2} =\frac{\omega_1}{\omega_2}[/tex]
Hence,the ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2 will be the ratio of the angular velocity.
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Which type of error is a false positive
Answer: Type I Error
Your'e at your new high school.....You go into the bathroom and there's students smoking in there. I mean like a real smoke fest. Some of them you know, most you don't as your'e the new freshman. Suddenly, the school security barges in to take everyone who's in the bathroom to the principal's office. You on the other hand was just trying to use the bathroom and never got to lol! You and everyone in the bathroom end up in the office about to get in big trouble. What do you do?
Answer:
Just get searched then go back to class
Explanation: similar situation
What can be described as a technology that uses high-frequency sound waves to create images?
Answer:
Ultrasound imaging (sonography) uses high-frequency sound waves to view inside the body.
Explanation:
Large rock rest on ground weight of rock is 8000n write down the size of contact force from the ground
The size of contact force from the ground is determined as 8000 N.
Size of contact force
According to Newton's third law of motion, action and reaction are equal and opposite.
The size of contact force from the ground is equal to the weight of the rock and it is calculated as follows;
Fd = Fn
Fd = 8000 N
Thus, the size of contact force from the ground is determined as 8000 N.
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What is the relative size and composition of the universe, a galaxy, and a solar system?
The solar system is smaller than a galaxy. Galaxies are composed of solar systems. The solar system is composed of planets revolving around a star (such as our sun). To put into perspective, there are about hundreds of billions of stars in our galaxy (the milky way). On the other hand, billions of galaxies make up the universe.
The speed of light is constant which is 299 792 458 m / s. The time is taken for light to reach an object can be used to measure the distance between objects in space. This is done by multiplying the time by the speed of light.
Distance in space is so vast and therefore impractical to use the basic SI units of meters and kilometers we use here on earth. Therefore the use of astronomical units and light years is used. Light years is the distance that light can cover in a year in the vacuum of space, while astronomical units is the distance between solar systems.