If a girl carries groceries up a flight of stairs, is she doing work on the groceries? Explain.
Answers
Answer:
Explanation:
Yes she is doing work. With or without the groceries, she is still doing work. She does more work with the groceries than without because Work is defined by F which is defined by mass. The mass increases with the groceries.
The work done is against the force of gravity.
Related Questions
Imagine you leave the dock on a fishing boat that travels east for 30 kilometers when the captain realizes he left the fishing rods on the dock. It takes him 40 minutes to travel out against the current but only 20 minutes to return to the dock.
Answers
Answer:
Average speed is 60 km/hr whereas average velocity is 0 km/ hr.
Explanation:
The average speed of the boat is 60 km/ hr while on the other hand, the average velocity of the boat is 0 km/ hr because average speed is the total distance covered by the boat in total time and average velocity is the displacement covered by the boat in total time. The total distance covered by the boat is 60 km and the total time is 60 minutes which is equals to one hour so the answer is 60 km/hr whereas the displacement is the shortest distance between initial and final position which is 0 in this case so 0 divided by 60 minutes or one hour is also 0.
If you want brainiest, can you help me?
Answers
Answer
?????
Explanation:
A physics student of mass 43.0 kg is standing at the edge of the flat roof of a building, 12.0 m above the sidewalk. An unfriendly dog is running across the roof toward her. Next to her is a large wheel mounted on a horizontal axle at its center. The wheel, used to lift objects from the ground to the roof, has a light crank attached to it and a light rope wrapped around it; the free end of the rope hangs over the edge of the roof. The student radius 0.300 m and a moment of inertia of 9.60 kg m^2 for rotation about the axle, how long does it take her to reach the side walk, and how fast will she be moving just beofre she lands?
Answers
Answer:
The speed of the student just before she lands, v₂ is approximately 8.225 m/s
Explanation:
The given parameters are;
The mass of the physic student, m = 43.0 kg
The height at which the student is standing, h = 12.0 m
The radius of the wheel, r = 0.300 m
The moment of inertia of the wheel, I = 9.60 kg·m²
The initial potential energy of the female student, P.E.₁ = m·g·h₁
Where;
m = 43.0 kg
g = The acceleration due to gravity ≈ 9.81 m/s²
h = 12.0 h
∴ P.E.₁ = 43 kg × 9.81 m/s² × 12.0 m = 5061.96 J
The kinetic rotational energy of the wheel and kinetic energy of the student supporting herself from the rope she grabs and steps off the roof, K₁, is given as follows;
[tex]K_1 = \dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex]
The initial kinetic energy, 1/2·m·v₁² and the initial kinetic rotational energy, 1/2·m·ω₁² are 0
∴ K₁ = 0 + 0 = 0
The final potential energy of the student when lands. P.E.₂ = m·g·h₂ = 0
Where;
h₂ = 0 m
The final kinetic energy, K₂, of the wheel and student is give as follows;
[tex]K_2 = \dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]
Where;
v₂ = The speed of the student just before she lands
ω₂ = The angular velocity of the wheel just before she lands
By the conservation of energy, we have;
P.E.₁ + K₁ = P.E.₂ + K₂
∴ m·g·h₁ + [tex]\dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex] = m·g·h₂ + [tex]\dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]
Where;
ω₂ = v₂/r
∴ 5061.96 J + 0 = 0 + [tex]\dfrac{1}{2} \times 43.0 \, kg \times v_{2}^2+\dfrac{1}{2} \times 9.60 \, kg\cdot m^2 \cdot \left (\dfrac{v_2}{0.300 \, m} }\right ) ^2[/tex]
5,061.96 J = 21.5 kg × v₂² + 53.[tex]\overline 3[/tex] kg × v₂² = 21.5 kg × v₂² + 160/3 kg × v₂²
v₂² = 5,061.96 J/(21.5 kg + 160/3 kg) ≈ 67.643118 m²/s²
v₂ ≈ √(67.643118 m²/s²) ≈ 8.22454363 m/s
The speed of the student just before she lands, v₂ ≈ 8.225 m/s.
The tendency to pull other objects toward it is called
Answers
Answer:
""gravity. the force that pulls on objects and causes acceleration if the objects are not balanced by an opposing force. speed. distance traveled per unit time. Newton's Second Law of Motion.""
Explanation:
A 1.70 m long string has a standing wave with 2 loops at a frequency of 38.4 Hz. What is the speed of the waves in the string? (Unit = m/s)
Answers
Answer:65.28
Explanation:
A long string has a standing wave with 2 loops at a frequency. The speed of the waves in the string is 65.28 m/s
What is frequency?The frequency is the number of cycles completed per second.
Given the length of the string l = is 1.70 m, no of loops n =2, frequency of wave f =38.4 Hz, then the speed of the waves is
f = nv /2l
Substitute the following values, we get
v = 38.4 x 2 x 1.70 / 2
v =65.28 m/s
Thus, the speed of the waves in the string is 65.28 m/s.
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Calculate the charge if one miliAmp flows for 1 second
Answers
Answer:
Thus 1 Ampere is the current is defined as flow of 1 coulomb charge through a conductor in 1 second.
Explanation:
Hope it helps
A 7 kg ball is push with a force of 28 N. What is the acceleration? .
Answers
Answer:
a = 4 m/s²
Explanation:
Given: 28 N, 7 kg
To find: Acceleration (a)
Solution: To find (a), divide force by weight
A = F ÷ m
= 28 ÷ 7
= 4 m/s²
Newtons are derived units, equal to 1 kg-m/s². In other words, a single Newton is equal to the force needed to accelerate one kilogram one meter per second squared.
Milk is a very weak acid. What might its pH value be ?
Answers
Answer:
pH value is between 6.5 and 6.8
Explanation:
Explanation:
Milk fresh from the cow typically has a pH between 6.5 and 6.7. The pH of milk changes over
it did work lollllllllllllllll
Answers
Answer:
Ok.............
hfjjjjjjlnggmm
Why isn't nuclear fusion used to generate electric energy in power plants?
A.
It requires extremely high pressure.
B.
It uses a very rare radioactive isotope.
C.
It releases less energy per gram than uranium does.
D.
It requires converting matter into energy.
Answers
Answer:
A) It requires extremely high pressure.
Explanation:
The reasons why we haven't been able to harness power from fusion is that its energy requirements are unbelievably, terribly high.
The correct statement is: "nuclear fusion requires extremely high pressure."
To find the correct statement among all the options, we need to know about nuclear fusion.
What is nuclear fusion?
Nuclear fusion is a nuclear reaction in which nuclei are fused to form another nucleus and releases some energy.How much pressure is required for nuclear fusion?
In a nuclear fusion reaction, 250 billions atmospheric pressure is required. One atmospheric pressure is 101325 pascals.Creating this much pressure is very much difficult.How much energy is released during nuclear fusion?
In nuclear fusion, 17.6 MeV energy is released in a single reaction. Since, two hydrogen atoms are participated, so energy released per nucleon is 8.8 MeV.What is the comparison of energy that released in nuclear fusion and fission?
In a nuclear fission reaction, 200 MeV energy is released in a single reaction and energy per nucleon is less than 1 MeV as an uranium has 238 nucleons.So, nuclear fusion reaction releases more energy as compared to that of nuclear fission.How does we get energy in the nuclear fusion reaction?
In a nuclear fusion reaction, two hydrogen atoms are fused to form a helium atom and the energy is released due the binding energy differences of hydrogen and helium atoms.Thus, we conclude that option (A) is correct.
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Which image best illustrates diffraction?
Answers
Answer:
The first option- Sun shining through clouds
Explanation:
When light passes from air into water at an angle of 60° from the normal, what is the angle of refraction? (40.6°)
Answers
Answer:
40.6°
Explanation:
The angle of refraction, when light passes from air into water at an angle of 60° from the normal, is 40.6°
What is Snell's law?It states that the ratio of sine of angle of incidence and angle of refraction is equal to the refractive index of second medium to the first medium.
sini/sinr =n₂ / n₁
Given, the light passes from air into water at an angle of 60° from the normal, the angle of incidence i = 60°, refractive index of air n₁ =1, refractive index of water n₂ = 1.333, then the angle of refraction is
sinr = sini x (n₁/n₂)
Plug the values, we get
sinr = sin60 x (1/1.333)
sinr = 40.6°
The angle of refraction is less than angle of incidence due to refraction.
Thus, the angle of refraction is 40.6°
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Suppose a blanket has a sock stuck to it due to static electricity. When you pull the sock off of the blanket, what happens to the potential energy between them?
Answers
Explanation:
When you pull the sock off of the blanket, the socks gain electrons out of blanket. This makes socks slightly negatively charged. The potential energy of the socks rise whereas potential energy of the blanket reduces. This happens because of exchange of electrons between socks and blanket.
Which statement describes one way that nuclear fission differs from nuclear fusion?
A. Nuclear fission can be sustained only in the Sun and other stars.
B. Nuclear fission can occur spontaneously.
C. The temperature required for nuclear fission is more than 15 million degrees Celsius.
D. It is more difficult to start and control nuclear fission,
Answers
Answer:
it is B
Explanation:
B
Statement B describes one way that nuclear fission differs from nuclear fusion in that nuclear fission can occur spontaneously.
What is nuclear power?The utilization of nuclear reactions to generate energy is known as a nuclear power. Nuclear fission, nuclear decay, and nuclear fusion processes are all sources of nuclear energy.
Nuclear power facilities currently produce the great bulk of the electricity generated by nuclear fission of uranium and plutonium.
Statement B describes one difference between nuclear fission and nuclear fusion in that nuclear fission can occur spontaneously.
Hence,option B is correct.
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Please help please real quick
Answers
Answer:
1. (a) The final velocity is 20 m/s
(b) The distance travelled is20 meters
2. The distance travelled by the train in the 30 seconds is 825 meters
3. The most correct option is;
(d) 53 km
4. The heat, developed by the electric iron is 15,000 joules
5. a) In the first network the resistance between A and B is 2 Ω
b) In the second network the resistance between A and B is 4Ω
c) In the third network the resistance between A and B is 6Ω
d) In the fourth network the resistance between A and B is 2Ω
Explanation:
1. (a) The parameters of the cheetahs motion are;
The initial motion (velocity) of the cheetah = 0 m/s (The cheetah starts from rest)
The acceleration of the cheetah, a = 2 m/s²
The duration of the acceleration of the cheetah, t = 10 seconds
The kinematic equation of the motion of uniform acceleration, of the cheetah can be written in the following form;
v = u + a·t
s = u·t + 1/2·a·t²
Where;
v = The final velocity
u = The initial velocity = 0 m/s
a = The acceleration of the cheetah = 2 m/s²
s = The distance traveled
∴ v = 0 + 2 × 10 = 20
The final velocity, v = 20 m/s
(b) From s = u·t + 1/2·a·t², we have;
s = 0 × 10 + 1/2 × 10 × 2² = 20
The distance travelled, s = 20 meters
2. The given details of the motion of the train are;
The initial velocity of the train, u = 20 m·s⁻¹
The acceleration of the train, a = 0.5 m·s⁻²
The duration of the train's acceleration, t = 30 seconds
Therefore, the distance travelled, 's', is given by; s = u·t + 1/2·a·t²
∴ s = 20 × 30 + (1/2) × 0.5 × 30² = 825
The distance travelled by the train in the 30 seconds, s = 825 meters
3. The given distance the truck covers with the average speed of 80 km/h, d₁ = 40 km
The distance the truck then covers with the average speed of 40 km/h, d₂ = 40 km
[tex]Average \ speed = \dfrac{Total \ distance}{Time}[/tex]
[tex]\therefore time, \, t = \dfrac{Total \ distance}{Average \ speed}[/tex]
The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(80 km·h) t₁ = 0.5 hour
The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(40 km·h) t₂ = 1 hour
The total time taken to cover both 40 km distances, t = t₁ + t₂
∴ The total time taken to cover both 40 km distances, t = (0.5 + 1) hour = 1.5 hours
The total distance covered at both speeds, d = d₁ + d₂
∴ d = 40 km + 40 km = 80 km
The average speed of the truck for the total distance, [tex]v_{average}[/tex] = d/t
∴ [tex]v_{average}[/tex] = 80 km/1.5 hours = 53.[tex]\overline 3[/tex] km/h ≈ 53 km/h
The average speed of the truck for the total distance, [tex]v_{average}[/tex] ≈ 53 km/h
The correct option is (d) 53 km
4. The heat, 'H', developed by the electric iron is given by the following formula;
H = I²·R·t
Where;
I = The current flowing in the electric iron = 5 A
R = The resistance of the iron = 20Ω
t = The time duration of the flow of the current = 30 s
∴ H = (5 A)² × 20 Ω × 30 s = 15,000 joules
The heat, developed by the electric iron, H = 15,000 joules
5. Let 'R' represent the resistance between A and B in each network
a) For the first network, we have;
1/R = 1/(2 + 2) + 1/(2 + 2) = 1/4 + 1/4 = 1/2
∴ R = 2 Ω
∴ The resistance between A and B is 2 Ω
b) For the second network, we have;
R = 1/(1/2 + 1/2) + 3 = 4
R = 4Ω
∴ The resistance between A and B is 4 Ω
c) For the third network, we have;
R = 2 + 1/(1/4 + 1/4) + 2 = 6
R = 6Ω
∴ The resistance between A and B is 6 Ω
d) For the fourth network, we have;
R = 1/(1/2 + 1/2) + 1/(1/2 + 1/2) = 2
R = 2Ω
∴ The resistance between A and B is 2 Ω
which best illustrates the relationships between a producer and a consumer
Answers
If the driver slammed on the brakes, what could happen to the crate?
Answers
How do you calculate kinetic energy without velocity
Answers
The kinetic energy is calculated by work done, The work done is equal to the change in kinetic energy when the object is at rest.
Kinetic energy (KE) is calculated using the formula:
KE = (1/2) × mass × velocity²
However, if you don't have the velocity value, it is not possible to calculate the kinetic energy accurately. Velocity is a crucial component in determining kinetic energy because it quantifies the object's speed and direction of motion.
But there is a special case when the object is at rest the change in velocity is equal to the work done.
Therefore, The kinetic energy is calculated by work done, The work done is equal to the change in kinetic energy when the object is at rest.
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A 15.0 cm object is 12.0 cm from a convex mirror that has a focal length of -6.0 cm. What is the height of the image produced by the mirror?
–5.0 cm
7.5 cm
-7.5 cm
5.0 cm
Answers
Answer:
-7.5
Explanation:
edge 2021
3. Neha travels 4 m towards the north, 3m towards the east, and then 7 m towards south, find the displacement and total distance traveled by her.
Answers
Answer:
Explanation:
Explanation: total displacement =3√2m. and total distance covered=14m. I hope this is right and helps u.
______________ controls the flow of electric current.
Answer!!!
Please
Answers
Answer:
Explanation:
Its resistor
In the diagram below, what is the potential difference across the 3.0-ohm resistor?
Answers
Answer:
3V
Explanation:
From the question given above, we can see clearly that the resistors are arranged in parallel connection. Hence, the same voltage will pass through the resistors i.e
Total voltage = voltage of 3 Ω = voltage of 6 Ω
From the question given above,
The total voltage = 3 V
Therefore,
Voltage of 3 Ω = total voltage
Voltage of 3 Ω = 3V
Thus, option 3 gives the correct answer to the question.
The diagram shows a roller-coaster track. Assume that the system is closed.
At point E, the roller-coaster car has just exited the vertical loop.
Which statement best describes the relative amounts of potential and kinetic
energy of a roller-coaster car at point E?
O A. Kinetic energy is at almost 0%, and potential energy is at almost
100%
O B. Both kinetic and potential energy are at almost 0%.
O C. Both kinetic and potential energy are at almost 100%.
OD. Potential energy is at almost 0%, and kinetic energy is at almost
100%
Answers
Answer: Potential energy is at almost 0%, and kinetic energy is at almost 100%
Explanation: took the exam
The roller coaster will lost its potential energy when its starts to excite the vertical loop and its kinetic energy will be maximum. Hence, option D is correct.
What is kinetic energy?Kinetic energy of a body is generated by its motion. Kinetic energy is proportional to the mass and square of the velocity of the object. Thus, as the speed of the object increase, kinetic energy increases.
Potential energy of a body is generated by virtue of its position. When a moving body slows down to stop, it gains potential energy and its kinetic energy starts decreasing.
When the roller coaster excites the vertical loop of the closed path, it loses its potential energy and kinetic energy increases to maximum since its moving the down loop with greater velocity. Thus, option D is correct.
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How does friction affect the output of machines?
Answers
Answer:
In a machine, friction reduces the mechanical advantage, or the ratio of output to input: an automobile, for instance, uses one-quarter of its energy on reducing friction. Yet, it is also friction in the tires that allows the car to stay on the road, and friction in the clutch that makes it possible to drive at all
Explanation:
hope it will help you
An object has an acceleration of 18.0 m/s/s. If the net force acting upon this object were doubled, then its new acceleration would be m/s/s.
Answers
Answer:
36.m/s/s
Explanation:
A ramp that is 8 meters long raises an object 2meters. What is the mechanical advantage
Answers
Does anbody know?????
Answers
Answer:
it is B
Explanation:
it is a compound lol
John has an object suspended in the air. It has a mass of 50 kilograms and is 50 meters above the ground. Calculate the object's potential energy?
Answers
m(object) = 50 kg.
h(object) = 50 m.
g = 9,8 m/s².
E(object) = m·g·h.
E(object) = 50 kg · 9,8 m/s² · 50 m.
E(object) = 24500 N·m = 24500 J = 24,5 kJ.
g - the acceleration of free fall.
mg - weight of the object.
A firework is launched with a force of 700 N and a momentum of 200 kg-m/s. How much time before is explodes?
Answers
Answer:
t = 0.28 seconds
Explanation:
Given that,
Force acting on a firework, F = 700 N
The momentum of the firework, p =200 kg-m/s
We need to find the time before it explodes. Ket the time be t. We know that, the rate of change of momentum is equal to external frce. So,
[tex]F=\dfrac{P}{t}\\\\t=\dfrac{P}{F}\\\\t=\dfrac{200}{700}\\t=0.28\ s[/tex]
So, the required time is equal to 0.28 seconds.
When two chemical atoms form a chemical bond, the expected result is that the electrons
A.)will be in the excited state
B.) will be equal to the number of protons
C.) will complete a noble gas configuration in both atoms
D.) will be removed completely from both atoms
Answers
Answer:
B
Explanation:
atoms with equal or similar electronegativity form covalent bonds in which the valence electrons are shared between the two atom
During the formation of a chemical bond, the expected result is that the electrons will complete a noble gas configuration in both atoms. Hence, option (C) is correct.
The given problem is based on the concepts and fundamentals of chemical bonds. The chemical bonds between the two atomic species is formed by sharing the electrons.
When the electrons from each of the atom is shared, they maintain a strong intermolecular bond, which is known as chemical bond. This chemical bond allows the element to achieve noble gas configuration.The electrons that is shared within the two atomic species are known as shared pairs.The shared pairs are bonded within the atomic species by means of Van der Waals force of attraction as as covalent interaction..Thus, we can conclude that during the formation of a chemical bond, the expected result is that the electrons will complete a noble gas configuration in both atoms. Hence, option (C) is correct.
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