Answer:
The efficiency of a screw is low because of friction.
Explanation:
A screw is a simple machine that is used to convert a torque to linear force and rotational motion to linear motion. The efficiency of a screw is given by :
[tex]\eta=\dfrac{Fl}{2\pi T}[/tex]
Where
l = pitch distance in mm
T = torque in N-m
The efficiency of screw is less because the output is less as compared to input or there is more input than output. This implies that there is more friction.
Hence, the correct option is (b) "friction".
When a substance undergoes a phase change it still has a definite....
Which law describes the magnetic field in a nonlinear wire?
Answer:
Lenz's law
Explanation:
Lenz's Law states that the induced tensions will be such that they oppose the variation of the magnetic flux that produced them; However, this law is a consequence of the principle of conservation of energy.
Lenz's Law: "The sense of the currents or induced electromotive force is such that it always opposes the cause that produces it, that is, the variation of the flow."
Thanks to the already named Lenz Law, the Faraday Law was completed, so it is common to also call it the Faraday-Lenz Law to honor its efforts in the problem, Russian physicists always use the name "Faraday-Lenz Law ".
The universe is mostly made up of what?
a. interstellar matter
b. particles of dust and gas
c. stars
d. empty space
Gravitational force between two objects depends on
Answer:
SIZE AND DISTANCE BETWEEN THEM
Which process forms rivers and valleys?
A. Oceanic-oceanic convergence
B. Exposed batholiths
C. Folding, uplift, and erosion
D. Volcanoes
When a 58g tennis ball is served, it accelerates from rest to a constant speed of 36 m/s. The impact with the racket gives the ball a constant acceleration over a distance of 35 cm. What is the magnitude of the net force acting on the ball?
Final answer:
The net force exerted on a tennis ball being served, which accelerates from rest to 36 m/s over a distance of 35 cm, is approximately 107.05 N.
Explanation:
To determine the magnitude of the net force acting on a tennis ball being served, we first need to calculate the acceleration of the ball. With an initial speed (vi) of 0 m/s, a final speed (vf) of 36 m/s, and a distance (d) of 0.35 m over which the acceleration occurs, we can use the kinematic equation vf^2 = vi^2 + 2ad to solve for acceleration (a).
vf^2 = 2ad → a = vf^2 / (2d) → a = (36 m/s)^2 / (2*0.35 m) → a ≈ 1845.71 m/s2.
Using this acceleration and the mass of the ball (m), we can then apply Newton's second law, Fnet = ma, to find the net force. The mass of the tennis ball is 0.058 kg (58 g). Thus, Fnet = ma = 0.058 kg * 1845.71 m/s2 → Fnet ≈ 107.05 N.
So, the net force exerted by the racket on the tennis ball is approximately 107.05 N.
If a resistor of R ohms is connected across a battery of E colts with internal resistance r ohms, then the power (in watts) in the external resistor is \[P = \frac{E^2R}{(R+r)^2}\]
If E and r are fixed but R varies, what is the maximum value of the power?
The maximum power in the external resistor R, when connected to a battery of E volts and internal resistance r, occurs when R equals r. This is a principle of electrical power in physics.
Explanation:This is a physics question involving a fundamental concept in electrical power and Ohm's Law. The given formula P = E^2R/(R+r)^2 is the power delivered to an external resistor R when it is connected to a battery with electromotive force (E) and internal resistance (r).
To find the maximum power in the external resistor R, we would differentiate the formula with respect to R and equal it to zero (since the maximum or minimum of a function translates to a derivative of zero). By doing this, R would be equal to r.
Therefore, the maximum power is distributed to the external resistor when the value of the resistor (R) equals the internal resistance (r).
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Which electrical protective device is designed to detect a difference in current between circuit wires and interrupt the circuit and stop the flow of electricity?
a. attach ungrounded, two-prong adapter plugs to three-prong cords and tools
b.do not operate electrical equipment when working in wet conditions
c. hold fingers on the switch while carrying a plugged-in tool
d. use gfci only when using double insulated power tools
. How much work in joules is done by a person who uses a force of 25 N to move a desk 3.0 m?
The work done by a person using a force of 25 N to move a desk 3.0 m is 75 Joules, calculated by multiplying the force and the distance.
Explanation:The concept in question is related to work and energy, under Physics. The work done by a force is defined as the product of the force and the distance over which the force acts, given by the formula: Work = Force x Distance. This implies that the work done is equal to the value of the force (in newtons) multiplied by the distance (in meters) over which the force is applied. In this case, a force of 25 N is acting to move a desk over a distance of 3 m. The work done can be calculated by multiplying the force and the distance: 25 N x 3 m = 75 J (Joules).
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A force that holds atoms together is a chemical .
A force that holds atoms together is a chemical "bond".
Chemical bonds hold atoms together and make brief associations that are fundamental to life. Sorts of chemical bonds including covalent, ionic, and hydrogen bonds and London dispersion forces.
The chemical bond can be thought of as a power that holds the particles of different components together in such compounds. It opens up the likelihood of a huge number of mixes of the components, and the formation of a large number of new compounds.
Answer:
Therefore, A force that holds atoms together is a chemical bond.
Explanation:
Chemical bond : A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.
Everything in the world around us is made up of atoms, which are tiny pieces of matter. Different atoms stick together to form all kinds of things in the world. A chemical bond is formed when two or more atoms are attracted to each other and form a chemical compound.
Types of chemical bonds including:
Ionic Bonds
Covalent Bonds
The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of
oxygen is __________ molecules per liter, assuming an atmospheric pressure of 739 torr and
a temperature of 29.5°C
A) 6.23
B) 0.00819
C) 4.93 × 1021
D) 3.75 × 1024
E) 5.07 × 1022
Final answer:
To calculate the concentration of oxygen in molecules per liter, we use the ideal gas law equation and substitute the given values to find the number of moles of oxygen. The concentration of oxygen is approximately 29.5 molecules per liter.
Explanation:
To calculate the concentration of oxygen in molecules per liter, we need to use the ideal gas law equation: PV = nRT. Rearranging the equation, we have n = PV/RT, where n is the number of moles of oxygen in the given volume, P is the pressure, V is the volume, R is the ideal gas constant, and T is the temperature.
Given the pressure of 739 torr, volume of 1 liter, and temperature of 29.5°C (which needs to be converted to Kelvin), we can substitute these values into the equation. The ideal gas constant R is 0.0821 L*atm/(mol*K).
Therefore, the concentration of oxygen in molecules per liter is:
n = (739 torr * 1 L) / (0.0821 L*atm/(mol*K) * (29.5+273) K)
n = 29.5
So the concentration of oxygen is approximately 29.5 molecules per liter.
two campers pull a canoe. If the force of friction acting on the canoe is 84 N, then how much work does the two campers need to do to keep the canoe in the middle of the river for a displacement of 50 m?
The work done by the two campers against frictional force is 4200 Joule.
What is force?The definition of force in physics is: the push or pull on a mass-containing item changes its velocity.
An external force is an agent that has the power to alter the resting or moving condition of a body. It has a direction and a magnitude. The application of force is the location at which force is applied, and the direction in which the force is applied is known as the direction of the force.
A spring balance can be used to calculate the Force. The Newton is the SI unit of force.
Frictional force acting on the he canoe: F = 84 N.
Displacement of the canoe: d = 50 m.
Hence, work done by the two campers against frictional force = force × displacement
= 84 N × 50 m
= 4200 Joule.
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The purpose of your physics lab is to determine the specific heat of a small metal cylinder. You and your group will use calorimetry, along with a ___________ probe and the law of heat exchange, to calculate specific heat of the metal.
Answer:
temperature probe
Explanation:
An ionic bond forms between sodium and chlorine when the sodium atoms______ elections
Donate
An ionic bond forms between sodium and chlorine when the sodium atoms donate elections
Explanation;Ionic bond is a type of bonds that results from transfers of electrons from one atom to another. This types of bond is formed between metals and non metals.Metals lose electrons to form cations (positively charged ion) and non metals gain electrons forming anions, negatively charged ion. In this case, sodium donates and electron to chlorine atom, thus they both achieve a stable electronic configuration forming ions.Which of the following conversion factors would you use to change 18 kilometers to meters?
A.) 1,000 m/1 km
B.) 1 km/1,000 m
C.) 100 m/1 km
D.) 1 km/100 m
Answer:
The answer is A) 1,000 meters = 1 Kilometer.
Explanation:
To convert 18 Kilometers into meters, one would have to multiply the figure given in Kilometer by 1000.
Therefore we have 18 x 1000
= 18,000.
So 18 Kilometers is also 18,000 meters when converted.
Cheers!
What force is needed to give a 4.5 kg bowling ball an acceleration of 9 m/s^2?
Which of the following statements is true about the nature of light?
A. Light behaves entirely as a particle
B. Light has properties of both particles and waves
C. Light behaves entirely as a wave
D. Light travels as a wave but does not carry energy ...?
Answer: The correct answer is "Light has properties of both particles and waves".
Explanation:
Light shows dual nature. It behaves as particle as well as waves.
Photoelectric effect is the phenomenon in which there is an emission of the electrons when the light of the particular frequency is incident on the surface of the metal.
The particle nature of the light is shown by photoelectric effect.
Reflection: Reflection is the phenomenon in which the light wave gets reflected from the surface without getting transmitted. It bounces back from the surface.
The wave nature of the light is shown by reflection.
Therefore, the correct option is (B).
A main sequence star cools and expands. It must be entering which stage?
A. white dwarf
B. black dwarf
C. red giant
D. neutron star ...?
Concave lens cause rays to _____.
A. come together
B. reflect
C. spread apart
What is transferred by electromagnetic waves?
If a person weighs 500 N on Earth, what would she weigh on Jupiter, where the acceleration due to gravity is 26 m/s2?
Show all work leading to your answer.
The person's weigh on Jupiter is 1326.52 N.
What is weight?Weight is a measurement of how much gravity is pulling on a body.
Weight is calculated using the formula: w = mg.
Given that weight is a force, its SI unit is also a force; hence, the SI unit of weight is the Newton (N). By examining the weight expression, we can see that it is dependent on mass and the acceleration caused by gravity.
Given that: a person weighs 500 N on Earth.
the acceleration due to gravity on Jupiter is 26 m/s^2.
Acceleration due to gravity on Earth is 9.8 m/s^2.
Hence, mass of the person
= Weight on Earth/acceleration due to gravity on Earth
=500 N/9.8 m/s^2.
= 51.02 kg.
Her weigh on Jupiter is
= mass of the person × acceleration due to gravity on Jupiter
= 51.02 kg × 26 m/s^2
= 1326.52 N.
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If Jupiter takes 9.9259 hours to rotate on its axis and has a tangential speed of 12,293 m/s what is its radius?
69,912 km !!!!!!!!!!!!!!!!!!!!!
If the kinetic and potential energy in a system are equal, then the potential energy increases. What happens as a result?
If potential energy in a system increases while its total mechanical energy remains constant, kinetic energy decreases equivalently. This exchange between kinetic and potential energy is an example of the conservation of mechanical energy. Changes in internal energy may also manifest as a change in temperature or energy within the system's structure.
When the potential energy in a system increases without a change in the mechanical energy (assuming no energy is lost to friction), the kinetic energy would decrease equivalently to conserve the total mechanical energy of the system. This is in accordance with the principle of conservation of energy. If an object, for example, is at a certain height above the ground and it is raised further, its potential energy increases due to its position. Consequently, if the object is in free fall, as the potential energy decreases, the kinetic energy increases until the object reaches ground level, where potential energy is at its minimum while kinetic energy is at its maximum.
When the potential energy in a system increases with kinetic energy being equal, it means the internal energy of the system is rising. This increase can be due to an increase in internal potential energy, internal kinetic energy, or both. The work done on the system equals the increase in internal energy.
Moreover, any increase in a system's internal energy that does not result in elevation or speed gain could translate to an increase in internal potential energy or internal kinetic energy, or both. An increase in the internal kinetic energy would generally be observed as an increase in temperature, while an increase in internal potential energy might be observed as energy stored within the structural or molecular configuration of the system.
If we apply this to the scenario of a child on a swing, as the child swings downward, the potential energy (due to height) decreases while kinetic energy increases. Conversely, as the child swings upward, the kinetic energy decreases and potential energy increases.
As the wave interacts with a wall, which kind of wave interaction is shown?
absorption
diffraction
refraction
reflection
The kind of wave interaction shown here is reflection.
What is meant by reflection ?
Reflection is the defined as the phenomenon by which a wave bounces back when it his on a medium or a plane.
Here,
The wave is shown as incident on the wall after that it is bounced back from the surface of the wall. Since, the wave is bounced back from the surface, we can say the wave interaction happened here is reflection. The surface of the wall here acts as the reflecting surface.
The wave that incident on the surface of the wall is called the incident wave. The wave that bounced back from the surface is called reflected wave.
If we draw a perpendicular line on the reflecting surface, it can be called the normal.
According to law of reflection, the incident wave, the reflected wave and the normal, all of them lies in the same plane. Here we can see that all of them are on the same plane. So, the law of reflection is valid in this situation.
Also, here only the direction of the wave is changed, which is the property of reflection.
Hence,
The kind of wave interaction shown here is reflection.
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best for growing most plants, which soil has good drainage and sufficient moisture?
Answer:
Sandy Loam soil
Explanation:
The ideal properties of a soil for growing plants is to have a reasonable drainage, good amount of aeration, pH value of the soil that allows the availability of all the elements such as potassium, iron, calcium, magnesium, nitrogen etc for growth. Loam soil has the features mentioned above and hence it makes a good choice.
What might you have if you dont feel well?
(Newton's Law of Motion) A person stands on a scale in an elevator. When the elevator is at rest, the scale reads 700 N. When the elevator starts to move, the scale reads 600N. (a) Is the elevator going up or down? Show your solution to support your answer. (b) What is its acceleration? ...?
The elevator is accelerating downward as the scale reads less than the person's weight. The acceleration of the elevator can be calculated using Newton's second law of motion and is approximately 1.4 m/s² downward.
Explanation:When a person stands on a scale in an elevator, the scale reading reflects the normal force, which is the force exerted by the scale on the person. If the scale reads 700 N when at rest and only 600 N when the elevator starts to move, it indicates that the elevator is accelerating downward.
This is because the normal force (and thus the scale reading) is less than the person's weight, which would only happen if the force due to acceleration opposes the force of gravity.
For part (b), to find the acceleration of the elevator, we can use Newton's second law of motion. The net force on the person can be calculated by subtracting the scale reading (the normal force) from the person's weight (gravitational force). Let m be the mass of the person and a be the acceleration. We have:
mg - FN = ma
Since mg is the weight (700 N) and FN is the scale reading (600 N):
700 N - 600 N = ma
100 N = ma
Using the given weight of 700 N and the acceleration due to gravity (9.8 m/s2), we find the mass m = 700 N / 9.8 m/s2 = approximately 71.43 kg.
Therefore, the equation becomes:
100 N = 71.43 kg * a
The acceleration a is about 1.4 m/s2 downward.
Temperature measures:
a. the kinetic energy of the random motion of molecules in an object.
b. the kinetic energy of the average motion of molecules in an object.
c. the potential energy of an object.
d. the motion of an object.
Temperature measures the average kinetic energy of the motion of molecules within an object. This means the faster the average molecular motion, the higher the temperature.
Explanation:The temperature of an object primarily measures
b. the kinetic energy of the average motion
of molecules in an object. The
kinetic energy
is the energy of motion. Every molecule in an object is in motion and hence possesses some kinetic energy. This motion could be translational (moving from one place to another), vibrational (moving back and forth), or rotational (spinning). The more kinetic energy they have, the faster they are moving, and the higher the temperature of the object. It's important to note that we are talking about the
average
kinetic energy per molecule, and not the total kinetic energy of all the molecules, as different molecules might be moving at different speeds.
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According to the big bang theory, the universe was once a very and hostile place.
a.cold
b.restless
c.hot
how many moles are in 95 g of Na?