A 250-m-wide river flows due east at a uniform speed of 2.8m/s. a boat with a speed of 8.6m/s relative to the water leaves the south bank pointed in a direction 30o west of north. what is the (a) magnitude and (b) direction of the boat's velocity relative to the ground? give the direction as the angle of the velocity from due north, positive if to the east and negative if to the west. (c) how long does it take for the boat to cross the river?
The scientific method includes _____. experimentation analysis of data research all of the above
Answer: Fourth option is correct i.e. all of the above.
Explanation:
Scientific method is a procedure of research where firstly problem is identified for which essential data is collected and then relevant hypothesis is formed and it is further tested.
So, It includes research, experimentation and observation, then analysis of data and formed hypothesis and tested it.
Hence, Fourth option is correct i.e. all of the above.
The closeness of measured values to an accepted value is the BLANK of the data ?
Which of the following rocks most likely resulted from compacting and cementing particles together?
Answer:
The answer is a sandstone. A sandstone is sedimentary rock composed of sand-size grains of mineral, rock, or organic material. It also contains a cementing material that binds the sand grains together and may contain a matrix of silt or clay-size particles that occupy the spaces between the sand grains.
Explanation: mark as brainly
Which statements can be supported by using a position-time graph? Check all that apply.
A negative slope results when an individual is moving toward the origin.
A straight line on the graph means the individual is moving at the same velocity.
A positive slope results when an individual is moving away from the origin.
The slope of the line gives the velocity of the individual.
The speed of an individual cannot be determined from this type of graph
A negative slope results when an individual is moving toward the origin.
This statement is correct because slope of position time graph always represents velocity and since slope is negative then it shows the velocity is towards negative direction here.
Negative direction velocity is always towards origin as it is towards negative X axis.
A straight line on the graph means the individual is moving at the same velocity.
This statement is correct because when graph is a straight line then it shows that slope of the graph will remain constant and since the slope of the graph means velocity so it means velocity will always remain constant in this case.
A positive slope results when an individual is moving away from the origin.
This statement is correct because slope of position time graph always represents velocity and since slope is positive then it shows the velocity is towards positive direction here.
Positive direction velocity is always away from origin as it is towards positive X axis.
The slope of the line gives the velocity of the individual.
This statement is correct because slope of position time graph always represents velocity.
Which of the following is true about semi-conductors: A. Exposing a crystal of a semiconductor to heat or light starts displacing valence electrons which then move throughout the crystal B. A material is classified as a semiconductor if its resistance to the flow of electric current is too low to permit it to be called a conductor C. Neither free electrons nor holes are considered charge carriers in a semi-conductor D. Gold and silver are important semiconductors
B. A material is classified as a semiconductor if its resistance to the flow of electric current is too low to permit it to be called a conductor.
Semiconductors contain a forbidden gap between the valence band and the conduction band, in which electrons energy levels are not allowed. The resistance of semiconductors decreases as their temperatures increases, which is opposite to how metals or other conductors behave.Semi-conductors: option (A), Exposing a crystal of a semiconductor to heat or light starts displacing valence electrons which then move throughout the crystal.
What are semi-conductors?Semiconductors are materials that have a conductivity between that of an insulator and a conductor. This means that they can conduct electricity, but not as well as conductors like copper or gold. Semiconductors are important for many electronic devices, including computers, cell phones, and solar cells.
When a semiconductor is exposed to heat or light, it can cause valence electrons to be displaced from their atoms. These electrons are then free to move throughout the crystal, which allows the semiconductor to conduct electricity. This process is called semiconductor doping.
Therefore the correct answer is option A.
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How long will it take to travel 200 km traveling 100 m/s?
In physics, the speed = distance/time formula allows us to calculate that a distance of 200,000 meters (or 200 km) at a speed of 100 m/s will take 2000 seconds to travel.
Explanation:The question you're asking is rooted in the physics concept of speed, distance, and time. The relation between these three is often represented by the formula: speed = distance/time. Here, you're given the speed (100 m/s) and the distance (200 km) and are asked to find the time.
First off, we need to convert the units so they match. Converting 200 kilometers into meters gives us 200,000 meters. Now, we simply rearrange the formula to solve for time, so we have time = distance/speed. Plugging in the values, we have time = 200,000m / 100 m/s.
The m (for meters) cancels out in the numerator and denominator, leaving us with: time = 2000 seconds. Therefore, it will take 2000 seconds to travel a distance of 200 km at a speed of 100 m/s.
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How does refraction support the particle theory of light? Particles bounce off surfaces similar to the way in which a ball bounces off a wall. Light slows down and bends when it moves from a less dense to a more dense medium. Forces act on the particles to push or pull them from one medium to another. As light passes through an opening, it spreads out in all directions.
Answer: The correct answer is "Forces act on the particles to push or pull them from one medium to another".
Explanation:
Refraction: It is the phenomenon in which light gets bend while travelling from one medium to the another due to change in the speed of light.
In this phenomenon, the light gets bend towards the normal when the light rays is travelling from rarer medium to denser medium. The light gets bend away from the normal when the light rays is travelling from denser medium to rarer medium.
Reflection: It is the phenomenon in which the light rays bounce back from the surface without getting absorbed.
Therefore, the correct option is "Forces act on the particles to push or pull them from one medium to another".
The refraction supports the particle theory of light by the statement as Forces act on the particles to push or pull them from one medium to another.
The phenomenon bending of a wave as it crosses from one medium to another is said to be refraction. The difference in density is the cause of the bending.
Refraction is a term that is used to describe the phenomenon of refraction. The change in direction of a wave traveling from one medium to another is known as refraction.
The refraction supports the particle theory of light by the statement as Forces act on the particles to push or pull them from one medium to another.
Hence the third statement is correct.
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A planet (or comet) will speed up as it approaches the sun
a. True
b. False
If a planet is closer to the sun, the gravitational force of the sun will get stronger on it and the planet will speed up. Therefore, the given statement is correct.
How sun have gravitational force?Planets revolve around the Sun the way the Moon revolves around the Earth in a solar system. Gravitational force can be described as a force that pulls objects. Therefore, Sun's gravity pulls on the planets the same as the Earth's gravity pulls down things that are not held up by some other force.
Heavier objects form a bigger gravitational pull than lighter ones thus the Sun acts with the strongest gravitational pull.
The gravitational field of a body is determined by two things: the mass of the body and the distance. Thus, the gravity of the Sun holds up to 9 planets and some dwarf planets.
The gravitational pull of the Sun is approximately 25 times greater than the Earth. The gravity of the sun pulls the planet toward itself changing the direction of the orbit into a curve.
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Which of the following states Bernoulli’s principle?
A. As the speed of a fluid decreases, the pressure within the fluid decreases.
B. As speed of a fluid increases, the pressure within decreases.
C. As the speed of a fluid changes, the pressure of the fluid remains constant.
D. None of the above
Answer:
B. As speed of a fluid increases, the pressure within decreases.
Explanation:
Which specialized science would you consult before cultivating your new field or farm for better and profitable yields? A. biotechnology B. biochemistry C. integrated pest management D.soil science
Answer: D. soil science
Explanation:
Soil science is necessary field which is required to be consulted before cultivating the field for profitable yields. This is because of the fact that the plants grows over the soil. The soil is an integrated mixture of inorganic or organic particles, water, air and minerals which are necessary ingredients for the growth of new plants. The soil of good quality can yield profitable crops.
A grapefruit falls from a tree and hits the ground 0.89 s later. how far did the grapefruit drop? what was its speed when it hit the ground?
A cart moves along a track at a velocity of 3.5 cm/s. When a force is applied to the cart, its velocity increases to 8.2 cm/s. If it takes the cart 1.5 seconds to reach 8.2 cm/s, what is the acceleration of the cart? Round your answer to the nearest tenth. cm/s2
The acceleration of the cart, given an initial velocity of 3.5 cm/s and a final velocity of 8.2 cm/s over a time period of 1.5 seconds, is approximately 3.1 cm/s².
Explanation:The question is looking for the acceleration of a cart when a force is applied to it. Acceleration is the rate at which an object changes its velocity. In this case, the initial velocity of the cart is 3.5 cm/s and the final velocity is 8.2 cm/s. This gives a change in velocity (Δv) of 8.2 cm/s - 3.5 cm/s = 4.7 cm/s. The time it takes for this change (Δt) is provided as 1.5 seconds. So, the acceleration (a) can be calculated using the formula a = Δv / Δt. Substituting the values we get, a = 4.7 cm/s / 1.5 s = 3.13 cm/s². After rounding to the nearest tenth, the acceleration of the cart is 3.1 cm/s².
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Which of the following is true concerning kinetic-molecular theory and heat transfer between relatively hotter Object A and relatively colder Object B?
A. Molecules of Object A collide with those of Object B, and the molecules in Object B move faster.
B. Molecules of Object A collide with those of Object B, and the molecules in Object B move at the same speed.
C. Molecules of Object B collide with those of Object A, and the molecules in Object A move faster.
D. Molecules of Object B collide with those of Object A, and the molecules in Object B move slower.
18. Which properties of light define light as a wave? (Points:5)
Answer:
Light is an electromagnetic radiation. It has both particle and wave nature. As a wave, light has amplitude, wavelength and frequency. These factors define a wave. Also, light undergoes interference and diffraction which are wave phenomena. On the other hand, light some times behaves as a particle. It is composed of photons. Each photon is a quanta of energy. Photoelectric effect can be explained on the basis of particle behavior of light.
Which of the following statements is true of planetary movement in our solar system?
A. Only the first three planets revolve around the Sun.
B. The Earth and planets all revolve around the Earth's moon.
C. The Sun revolves around the Earth and other planets.
D. The Earth and other planets revolve around the Sun.
The correct statement about planetary movement is that the Earth and other planets revolve around the Sun. This follows Kepler's first law, which states that planets move in elliptical orbits with the Sun at one focus. The geocentric model has been debunked in favor of the heliocentric model.
Explanation:The true statement about planetary movement in our solar system is D. The Earth and other planets revolve around the Sun. The solar system consists of eight planets, including Earth, all of which orbit the Sun. Moreover, these planets follow Kepler's first law of planetary motion, which states that each planet moves around the Sun in an orbit that is an ellipse, with the Sun at one focus of the ellipse. These orbits are not centered directly on the Sun, but the Sun occupies one of the foci of the orbital ellipses.
Contrary to historical belief, we now understand through the work of Nicolaus Copernicus and the further confirmation by Johannes Kepler's laws that the geocentric model (Earth-centered universe) is incorrect, and that the heliocentric model (Sun-centered universe) accurately describes our solar system. This heliocentric model is supported by extensive observations and laws, such as those formulated by Kepler, and has been a fundamental concept in astronomy for centuries.
A guitar string has a linear density of 8.30 ✕ 10−4 kg/m and a length of 0.660 m. the tension in the string is 56.7 n. when the fundamental frequency of the string is sounded with a 196.0-hz tuning fork, what beat frequency is heard?
If you push for an hour against a stationary wall, you do no work
Final answer:
No work is done when pushing against a stationary wall because in physics, work requires force and displacement, and the wall does not move. The incorrect idea concerning the tennis ball involves a misunderstanding of force and energy transfer upon impact with the wall. Therefore, the correct option is B.
Explanation:
If you push for an hour against a stationary wall, you do no work at all (Option B). This might seem counterintuitive because pushing against a wall requires effort and you can feel tired as a result. However, in physics, work is defined as the transfer of energy, and it requires both a force and displacement in the direction of the force. Since the wall does not move, there is no displacement, and therefore, no work is done on it. Even though energy is consumed by the person pushing the wall, it is not transferred to the wall, thus fulfilling the requirements of the definition.
In the scenario of hitting a tennis ball against a wall, the incorrect idea is that the ball loses part of the force when it hits the wall and hence doesn't bounce back as fast. However, it's not the force that is being transferred and lost, it's the energy of the ball that is converted into other forms, like sound or heat, upon collision. The muscles in your arm do initiate the force that propels the ball, but forces in this context are a result of the interactions between objects and not just from muscles.
If the density of the full can is 1.1 g/cc, what is its mass? Show work
What method of separation would work best on a homogeneous mixture salt water?
Select all that apply.
A) filtration
B) distillation
C) evaporation
D) screening
The number of oscillations that a wave completes per unit of time in called its _______.
energy transformation occurs as energy changes from one form to another. as these transformation occurs, which of the following happens?
Ross was taking a walk on a cold, winter day. A few minutes into his walk, Ross's hands got cold, so he rubbed them together to warm them. Ross warmed his hands by using:
What particles exist within plasma that do not exist in other states?
A. molecules
B. atoms
C. free electrons
D. free neutrons
**what do you think? thank you!:),
How does the sun's energy most directly influence precipitation in an area?
Final answer:
The Sun's energy directly influences precipitation by driving the water cycle, where solar warmth causes evaporation, and cooled water vapor in the atmosphere condenses into clouds leading to precipitation. Warmer air holds more moisture, making regions like the tropics receive more rainfall, while areas around 30 degrees latitude are drier.
Explanation:
How the Sun's Energy Influences Precipitation
The Sun's energy directly affects precipitation by driving the water cycle on Earth. Solar energy heats water in oceans, rivers, and lakes causing it to evaporate into water vapor. This evaporated water rises and cools in the atmosphere, where it condenses into clouds. The temperature of the air plays a crucial role in the capacity to hold water vapor; warmer air can hold more moisture. Consequently, areas such as the tropics, which experience high temperatures, usually have higher amounts of precipitation because the warm air rises and cools, leading to frequent rainstorms.
Conversely, regions around 30 degrees north and south latitude, such as the major deserts, receive less precipitation partly due to descending air conditions that produce warmer, drier air. The sun's energy not only influences evaporation rates but also impacts wind and air mass movements, which in turn affect precipitation patterns globally.
Overall, changes in atmospheric water vapor content, evaporation rates, and wind patterns all interplay to determine specific precipitation events, and the Sun's energy is a fundamental driver of these processes.
Radiation, conduction, and convection are methods of energy transfer. Of these methods, radiation is the only one in which energy can be transferred through _______.
also explain im not so sure about this stuff ^-^
A. matter.
B. liquids.
C. solids.
D. space.,
Answer:
D. space.
Explanation:
An adventurer pulls a loaded sled with a mass of 56kg along a horizontal meadow at a constant speed. The coefficient of kinetic friction between the sled and the grass is 0.45 and the angle of the rope between the sled and the adventurer is 55 degrees. What is the tension in the rope?
Final answer:
To find the tension in the rope, we first calculate the force of friction as 246.96N, and then using the angle of the rope, we find the tension required to move the sled at a constant speed to be approximately 431.79N.
Explanation:
An adventurer pulls a loaded sled with a mass of 56kg along a horizontal meadow at a constant speed. The coefficient of kinetic friction between the sled and the grass is 0.45 and the angle of the rope between the sled and the adventurer is 55 degrees. To find the tension in the rope, we first calculate the force of friction, which opposes the motion of the sled, and then use this to find the tension in the rope taking the angle into account.
The force of friction (Ffriction) is calculated using the formula: Ffriction = μ * N, where μ is the coefficient of kinetic friction and N is the normal force. In this scenario, since the sled is on a horizontal surface, the normal force is equal to the weight of the sled (mass × gravity), which is 56kg × 9.8m/s2 = 548.8N. Therefore, Ffriction = 0.45 × 548.8N = 246.96N.
Because the sled moves at a constant speed, the tension's horizontal component (Tx) offsets the force of friction. The tension in the rope also has a vertical component (Ty) affecting the normal force, but it doesn't affect the calculation for the force needed to maintain constant speed on a horizontal surface. The tension T can be found using the component form: Tx = T × cos(θ). Rearranging this for T, we get T = Tx / cos(θ) = 246.96N / cos(55°), which calculates to approximately 431.79N.
What is a lack of physical, social, or economic access to safe and nutritious foods called? A) famine B) food security C) food shortage D) food insecurity
The lack of physical, social, or economic access to safe and nutritious foods called food insecurity. The lack of food by a small amount is called food shortage.
What is food insecurity ?The lack of physical, social, or economic access to safe and nutritious foods is what is called food insecurity. Long-term or transient food insecurity are both possible.
A variety of variables, such as income, employment, race/ethnicity, and handicap, may have an impact. When there is little or no money to buy food, there is a greater chance of food insecurity.
In 2020, 28.6% of low-income households experienced food insecurity, compared to 10.5 % nationally. 2 The level of food security within a household might suffer as a result of unemployment.
Among low-income communities, high unemployment rates make it more challenging to cover basic food demands for households. 10 Additionally, compared to kids with working parents, kids with unemployed parents had greater rates of food insecurity.
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At what speed do a bicycle and its rider, with a combined mass of 120 kg , have the same momentum as a 1800 kg car traveling at 5.6 m/s ?
The bicycle and rider need to have a speed of approximately 84 m/s to have the same momentum as the car.
Explanation:The momentum of a moving object is given by the formula:
Momentum = mass × velocity
To find the speed at which a bicycle and its rider, with a combined mass of 120 kg, have the same momentum as a 1800 kg car traveling at 5.6 m/s, we can set up an equation:
120 kg × speed of the bicycle and rider = 1800 kg × 5.6 m/s
Solving for the speed of the bicycle and rider:
Speed of the bicycle and rider = (1800 kg × 5.6 m/s) / 120 kg
Speed of the bicycle and rider ≈ 84 m/s
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To have the same momentum as an 1800 kg car traveling at 5.6 m/s, a bicycle, and its rider, with a combined mass of 120 kg, must travel at 84 m/s. This is established using the concept of momentum which is calculated by multiplying an object's mass and velocity.
Explanation:The subject matter of your question falls under physics, particularly the concept of momentum. Momentum is the product of an object's mass and its velocity. It's a vector quantity, which means it has both magnitude and direction.
The formula for momentum is p = mv, where 'p' is momentum, 'm' is mass, and 'v' is velocity or speed. To find the speed at which a bicycle and its rider, with a combined mass of 120 kg, have the same momentum as an 1800kg car traveling at 5.6m/s, we need to equate their momentums and solve for the speed of the bicycle and rider.
We know that p(car) = p(bicycle + rider)
Therefore, m(car)*v(car) = m(bicycle + rider)*v(bicycle + rider)
Substituting the known values, we get 1800 kg * 5.6 m/s = 120 kg * v(bicycle + rider)
Solving for v(bicycle + rider), we find that the speed of the bicycle and rider should be 84 m/s to have the same momentum as the car.
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How many planets are there?