Answer: The true statement form the given statements is "the athlete is not doing any work because he does not move the weight.".
Explanation:
The formula for work done is as follows,
[tex]W = Fscos\theta[/tex]
Here, F is the force, s is the displacement and theta is the angle between force and displacement.
In the given problem, an athlete holds 50 kg on his head for 10 seconds. The angle between force and displacement is 90 degree.
In this case, the work done is zero.
Therefore, the athlete is not doing any work because he does not move the weight.
How many neutrons does element X have if its atomic number is 48 and its mass number is 167?
How many neutrons?
When is thermal equilibrium achieved between two objects?
A.
when thermal energy is no longer transferred
B.
when one objects is hotter than the other
C.
when both objects have the same temperature
D.
when the particles in one object have more kinetic energy
Final answer:
Thermal equilibrium between two objects is achieved when they are at the same temperature, resulting in no net flow of thermal energy between them. This satisfies the conditions of the zeroth law of thermodynamics. So the correct option is C.
Explanation:
Thermal equilibrium is achieved between two objects when both objects have the same temperature, which corresponds to option C. At this point, no thermal energy is transferred between the objects because their molecules have the same average kinetic energy. This concept is rooted in the zeroth law of thermodynamics, which also suggests that if object A is in thermal equilibrium with object B, and object B with object C, then objects A and C are also in thermal equilibrium. Therefore, the net flow of heat ceases once the objects reach the same temperature.
Key Points:
Thermal equilibrium occurs when two bodies can exchange energy but do so without a net energy transfer.Heat is the transfer of energy caused by a temperature difference and stops when temperatures equalize.The zeroth law of thermodynamics justifies the concept of temperature and standard measurement tools like thermometers.Given the velocity v=ds/dt and initial position of a body moving along a coordinate line, find the body's position at time t. v = sin(pi(t)) s(-6)=0. ...?
The current in a wire is 0.72a calculate the charge that passes through the wire in 4s
How many dwarf planets are there in our solar system?
Our Sun and Earth are part of what we call our solar system. There are eight big planets and five small, dwarf planets in the solar system. Each planet orbits the Sun.
The distance formula can be used to prove a quadrilateral has select one:
a. a right angle
b. congruent angles
c. parallel sides
d. congruent sides
Answer: d. congruent sides
Explanation:
The distance formula is a formula in geometry to calculate the length of a line segment having two distinct point on a Cartesian plane
The distance formula to calculate the distance between two distinct points A(a,b) and B(p,q) is given by :-
[tex]\text{d}=\sqrt{(p-a)^2+(q-b)^2}[/tex]
Since it is used to calculate the distance between two points therefore, it is used to check whether a quadrilateral has congruent sides.
Hence, the distance formula can be used to prove a quadrilateral has congruent sides.
Only electrons orbit the nucleus of an atom true or false
The statement that only electrons orbit the nucleus of an atom is false.
Explanation:The statement that only electrons orbit the nucleus of an atom is false. In an atom, there are several subatomic particles, including protons and neutrons, that also make up the nucleus. Electrons, on the other hand, are found in energy levels or orbitals outside the nucleus. These energy levels determine the arrangement and behavior of electrons in an atom.
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You need to move a 105kg sofa to a diffrent room. It takes a force of 102 N to start it moving. What is the coefficient of static friction between sofa and carpet? ...?
For the cart without a washer,how does the potential energy at the top of the ramp compare to the kinetic energy at the bottom of the ramp?
How many complete revolutions are needed to draw the angle 725°?
a. 3
b. 1
c. 2
d. 4
Answer:
[tex]725\ degree=2\ revolution[/tex]
Explanation:
We know that 1 complete revolution is equal to 360 degrees. We need to find the number of complete revolution needed to draw the angle of 725 degrees.
Since, 1 revolution = 360 degrees
or
[tex]1\ revolution=2\pi \ radian[/tex]
[tex]1\ degree=\dfrac{1}{360}\ revolution[/tex]
[tex]725\ degree=\dfrac{725}{360}\ revolution[/tex]
[tex]725\ degree=2.01\ revolution[/tex]
or
[tex]725\ degree=2\ revolution[/tex]
So, to draw an angle of 725 degrees, there are 2 revolutions. Hence, this is the required solution.
A ball rolls off the edge of a horizontal roof at 10 m/s. 2 seconds later, the speed of the ball will be? a. 10 m/s b. 19.6m/s c. 29.6 m/s d.22 m/s ...?
The ball will have a speed of 22 m/s after 2 seconds.
Explanation:When the ball rolls off the edge of a horizontal roof, it becomes a projectile and begins to fall under the influence of gravity. The horizontal component of its velocity remains constant, so after 2 seconds, the ball will still have a horizontal speed of 10 m/s.
However, the vertical component of its velocity will increase due to the acceleration of gravity. The acceleration due to gravity is approximately 9.8 m/s². So after 2 seconds, the ball will have accelerated 9.8 m/s² for 2 seconds, resulting in a change in velocity of 19.6 m/s.
To find the speed of the ball after 2 seconds, we need to find the resultant velocity by using the Pythagorean theorem. The initial horizontal velocity is 10 m/s and the change in vertical velocity is 19.6 m/s. So:
Resultant velocity = sqrt((10)^2 + (19.6)^2) = 22 m/s.
Therefore, the correct answer is d. 22 m/s.
Final answer:
The final speed of a ball rolling off a horizontal roof with an initial horizontal speed of 10 m/s after 2 seconds will be 22 m/s, due to the additional vertical velocity it gains from gravity. So the correct option is d.
Explanation:
A ball rolls off the edge of a horizontal roof at 10 m/s. To determine the speed of the ball 2 seconds later, we use the equation for the final velocity of an object in free fall: v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration due to gravity (9.8 m/s²), and t is time. Since the ball rolls off horizontally, the initial vertical velocity is 0, and the horizontal velocity remains the same since there's no air resistance. Hence, the horizontal velocity after 2 seconds is still 10 m/s. For the vertical velocity, we use u=0, a=9.8 m/s², and t=2 s:
Vertical velocity after 2 seconds = 0 m/s + (9.8 m/s² * 2 s) = 19.6 m/s
We now have both horizontal and vertical velocities. The speed of the ball will be the vector sum of these two velocities, calculated using the Pythagorean theorem:
Total speed = sqrt(10 m/s² + 19.6 m/s²) = 22 m/s
Therefore, the correct answer is (d) 22 m/s.
The smallest unit of an element that maintains the properties of that element is a (n)
Can centripetal force ever do work on an object? ...?
What is the basis for dividing the atmosphere into four layers?
The basis for dividing the atmosphere into four layers is due to the temperature gradient of the layers.
What is meant by atmosphere ?The layer of gases that covers Earth is known as the atmosphere. The gravitational pull of the planet's neighbor, Earth, keeps it close to the surface.
Here,
The troposphere, stratosphere, mesosphere, thermosphere, and exosphere are the principal layers of the atmosphere, listed in order from lowest to highest. The troposphere of the planet is a layer of air that rises from the surface of the planet to an average height of 12 kilometres (7.5 miles), however it is higher in the equator and lower at the poles.
Temperature gradient is the term used to describe a difference in temperature with distance. According to the temperature gradient inside each layer, the Earth's atmosphere is classified into layers, and each layer's heat source defines its own temperature gradient.
Hence,
The basis for dividing the atmosphere into four layers is due to the temperature gradient of the layers.
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Which kind of force do you exert on an object when you pull it toward you?
A. Applied Force
B. Attractive Force
C. Drag Force
D. Normal Force
By definition we have to:
Applied force: It is the external force that acts directly on a body.
Therefore, we can say that if you have an object and push it towards yourself, you are exerting an external force on the object.
This external force was not acting on the object previously, therefore, it is a force that you are applying at that moment.
Answer:
you exert an Applied Force on an object when you pull it towards you
A. Applied Force
According to Newton's first law of motion, what is required to make an object at rest move?
during nuclear fission and fusion matter that seems to disappear is actually converted into
During nuclear fission and fusion matter that seems to disappear but is actually converted into energy.
What is nuclear fission and fusion?When the slow moving neutrons are bombarded with the heavy radioactive nuclei, the product is the more number of neutrons are produced with the large amount of energy. This multiplying process is called nuclear fusion.
The amount of energy produced in such a reaction can be calculated using the equivalence of mass and energy relationship.
E = mc²
The same happens in nuclear fusion where large amount of energy is needed to make more heavy nuclei.
Thus, during nuclear fission and fusion matter that seems to disappear but is actually converted into energy.
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During nuclear fusion and fission, the matter that seems to disappear is converted into energy.
This is explained by Einstein's famous equation which shows that energy and mass are interchangeable:
E = mc²Here:
E = Energym = mass of the objectc = speed of lightThis equation explains that:
In nuclear fission, the nucleus of an atom splits into smaller nuclei, releasing a significant amount of energy. In nuclear fusion, smaller atomic nuclei combine to form a larger nucleus, also releasing substantial energy. The small mass lost in these reactions is converted into energy.That is why during nuclear fusion and fission reactions, the matter that seems to disappear is actually converted into energy.
an is_____ produced around a wire when electrical current is in the wire
Which of the following is an example of speed only?
A. 25 kilometers per hour (25 km/h)
B. 45 miles per hour to the east (45 mph to the east)
C. 60 meters per hour per second (60 m/h s)
...?
25 kilometers per hour (25 km/h) is an example of speed only.
Thus, Velocity is the pace and direction of an object's movement, whereas speed is the time rate at which an object is travelling along a path.
In other words, velocity is a vector, whereas speed is a scalar value. For instance, 50 km/hr west denotes the velocity of a car whereas 50 km/hr (31 mph) denotes the speed at which it is moving down a route.
The average speed of an object is determined by dividing the distance traveled by the amount of time it takes the object to go the distance, which is a pretty simple mathematical formula and speed.
Thus, 25 kilometers per hour (25 km/h) is an example of speed only.
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a 155 gram sample of copper was heated to 150.0ºC then placed into 250 gram of water at 19.8ºC. (The specific heat of copper is 0.385J/gºC.)Calculate the final temperature of the mixture. (assume no heat loss to the surroundings)
If you do 200 joules of work using a force of 5 newtons,over what distance will the force applied
A star is a luminous ball of hot ______ held together by its own gravity.
A. dark matter
B. energy
C. plasma
Answer:
C) plasma
A star is a luminous ball of hot plasma held together by its own gravity.
Explanation:
Stars are formed from molecular clouds. When a cloud receives an impact wave from a near supernova or another astronomical event, as a consequence, it will start to collapse under its gravity, until it breaks in small pieces (each of this pieces will become a star).
Stars are submitted to a hydrostatic equilibrium (its gravitational force pulls inward and its nuclear pressure pulls outward), that gave rise to higher pressures and higher temperatures, those temperatures allow atoms being completely ionized¹. Stars are compounded with a gas mixture of atoms, free protons and free electrons (plasma).
¹Ionized: When an atom loses electrons.
Sophie says that geologic maps do not matter because she gets no benefits from them. Why is Sophie wrong? a. She can see the ranges of mountains near her house. B. She needs to learn how to read geologic maps in school. C.She benefits from products that use minerals found using geologic maps. D.She can see the weather and dress appropriately.
A fluid is
A.) a solid substance made up of crystals.
B.) a substance that has a definite shape and a definite volume.
C.) a substance that flows
D.) a substance that melts at a distinct temperature.
If energy efficiency is improved, the cost of energy would decrease and _____. more coal would be available less electricity would be used homes would cost significantly less energy star appliances would no longer be necessary
Answer:
less energy would need to be generated.
Explanation:
What is efficiency?
Energy efficiency just means that you need less energy for the same consumption or demand.
In distribution and transportation of energy we lose some of the energy generated at the power plants, be it in the form of heat radiation because of the resistance of power cables or in the form of electromagnetic radiation, so if we improve efficiency, then less energy is lost in those two ways to power the same demand. Putting it simply, let's say your house demands 10kW, and the cable connecting you with the utility loses 1kW, then:
1kW+10kW = 11kW <- That needs to be generated
But if we improve that efficiency by 50% then the loses are cut by half, 1kW/2=0.5kW, so:
0.5kW+10kW = 10.5 kW <- 0.5 kW less that need to be generated. Multiply that by the number of homes in America for example and you have tremendous power-saving potential
What happens when two objects made out of diffferent materials are rubbed together?
a metal sphere with a mass of 90 kg rolls along at 16m/s and strikes a stationary sphere having a mass of 140kg. the first sphere stops completely. at what speed does the second sphere move away at?
Selecting a signaling site and putting your signal in a suitable location is critical. a signaling site is defined as any site, based on your situation that enhances signaling efforts and the likelihood for the signal to be detected by friendly forces. what is a signaling site criterion?
A signaling site criterion involves selecting a location based on characteristics that enhance the likelihood of successful signal transmission, much like the site location analysis done by geographers.
Explanation:A signaling site criterion is an important factor when selecting a location for sending out signals so that they can be effectively detected by friendly forces or intended recipients. This concept is similar to site location analysis in geography, where geographers assess various factors to determine the most advantageous location for a city, business, or other establishments based on site and situation factors. The criteria focus on attributes such as the availability of resources, the location's visibility, accessibility, and the likelihood of successful signal transmission. Like how a city benefits from a good harbor or central location, a signaling site should enhance the probability of signal detection while considering both the physical characteristics of the site and the external factors affecting its efficacy.
As a certain object falls, its position s (in meters) above ground after t seconds is given by s(t)=20-5t^2. Whats the average velocity of the object on the interval from t=1 to the time .5 seconds later?? from t=1 to the time .1 seconds later?
What is a circuit. .