Một vật được ném lên trên theo phương thẳng đứng. Người quan sát
thấy vật đó đi qua vị trí có độ cao h hai lần và khoảng thời gian giữa hai lần đó là
t. Tìm vận tốc ban đầu và thời gian chuyển động của vật từ lúc ném đến khi vật
rơi về vị trí ban đầu.

Answers

Answer 1

Answer:

Language -English plz I cant understand


Related Questions

write any two physical hazard occuring in the late choldhood​

Answers

Answer:

Hazards during late childhood

Health Problems: Chronic health ailments like T.B., Pneumonia etc will hinder the child's motor abilities.Accidents: School age children are more adventurous in nature, they run fast, play hard, ride bicycles and scooters and engage in a variety of sports.

Write the derivation and unit of impulse​

Answers

Answer:

impulse applied to an object produces an equivalent vector change in its linear momentum, also in the resultant direction. The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram meter per second (kg⋅m/s).

calculate horizontal distance travelled by a ball travelling with a speed of 20root2 mper sec without hitting ceiling of height 20 m per sec​

Answers

Calculate the horizontal distance travelled by a ball throw with a velcoity 20 sqrt 2 ms^(-1) without hitting the ceiling of an anditorium of heith 20 m. Use g= 10 ms^(-2). =(20√2)2sin2×45∘10=9800×1)10=80m .

HOPE SO IT HELPS YOU

Electrons are emitted from a surface when light of wavelength 500 nm is shone on the surface but electrons are not emitted for longer wavelengths of light. The work function of the surface is

Answers

Explanation:

Given: [tex]\lambda = 500\:\text{nm} = 5×10^{-7}\:\text{m}[/tex]

[tex]\nu = \dfrac{c}{\lambda} = \dfrac{3×10^8\:\text{m/s}}{5×10^{-7}\:\text{m}}[/tex]

[tex]\:\:\:\:\:= 6×10^{14}\:\text{Hz}[/tex]

The work function [tex]\phi[/tex] is then

[tex]\phi = h\nu = (6.626×10^{-34}\:\text{J-s})(6×10^{14}\:\text{Hz})[/tex]

[tex]\:\:\:\:\:\:\:= 3.98×10^{-19}\:\text{J}[/tex]

The work function of the surface is equal to 3.98 × 10⁻¹⁹J.

What are frequency and wavelength?

The frequency can be explained as the number of oscillations of a wave in one second. The frequency has S.I. units of hertz.

The wavelength can be explained as the distance between the two adjacent points such as two crests or troughs on a wave.

The expression between wavelength (λ), frequency, and speed of light (c) is:

c = νλ

Given, the wavelength of the light, ν = 500 nm

The frequency of the light can determine from the above-mentioned relationship:

ν = c/λ= 3 × 10⁸/500 × 10⁻⁹ = 6 × 10¹⁴ Hz

The work function = h ν =  6 × 10¹⁴ × 6.626 × 10⁻³⁴

φ = 3.98 × 10⁻¹⁹J

Therefore, the work function of the surface is 3.98 × 10⁻¹⁹J.

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A linear accelerator can be used to accelerate which of the following?
Question 3 options:

protons and electrons

protons and neutrons

protons only

protons, electrons, and neutrons

Answers

Answer: protons and electrons

A single force acts on a particle situated on the positive x axis. The torque about the origin is in the negative z direction. The force might be:_______.
A. in the positive y direction
B. in the negative y direction
C. in the positive x direction
D. in the negative x direction

Answers

C maybe don’t count on it 100%

A single force acts on a particle situated on the positive x axis. The torque about the origin is in the negative z direction. The force might be in the negative y direction. Thus, option B is correct.

To determine the force that could generate a torque in the negative z direction, we need to consider the right-hand rule for cross products. The torque vector, denoted by τ, is given by the cross product of the position vector, r, and the force vector, F:

[tex]τ = r × F[/tex]

In this case, the position vector, r, points along the positive x-axis. The negative z-direction torque indicates that the force vector must be perpendicular to both the position vector and the negative z-axis.

Using the right-hand rule, we can determine that the force vector must be in the negative y-direction, which is option B.

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who was the youngest female to give birth​

Answers

Answer:

5 years old 7 months and 21 days

Explanation:

Answer:

lina marcela medina de jurado

The Earth’s orbit around the Sun is slightly elliptical. At Earth's closest approach to the Sun (perihelion) the orbital radius is 1.471×10^11m, and at its farthest distance (aphelion) the orbital radius is 1.521×10^11m.

a. Find the difference in gravitational potential energy between when the Earth is at its aphelion and perihelion radii.
b. If the orbital speed of the Earth is 29,290 m/s at aphelion, what is its orbital speed at perihelion?

Answers

Answer:

1.25

Explanation:

May someone help...please. Pretty please...

If a person is 18 % shorter than average, what is the ratio of his walking pace (that is, the frequency 'f' of his motion) to the walking pace of a person of average height? Assume that a person's leg swings like a pendulum and that the angular amplitude of everybody's stride is about the same.
f(short)/f(avg)=?

Answers

We have that  the ratio of his walking pace  to the walking pace of a person of average height is

[tex]\frac{V_2}{V_1}=1.10[/tex]

given the assumption and the calculation given below

From the question we are told that:

Consider a person 18\% shorter than average

Let average height of a person be [tex]10m[/tex]

Therefore

The height of an [tex]18\%[/tex] shorter man is mathematically given as

H=10*0.18

H=8.2m

Generally, the equation for velocity is mathematically given by

[tex]v=\frac{1}{2\pi} \sqrt{{g}{l}}[/tex]

Where we have the  Assumption that a person's leg swings like a pendulum and that the angular amplitude of everybody's stride is about the same

Therefore

[tex]\frac{V_1}{V_2}=\frac{l_1}{l_2}[/tex]

[tex]\frac{V_1}{V_2}={82}{100}[/tex]

[tex]\frac{V_2}{V_1}=1.10[/tex]

In conclusion

The ratio of his walking pace (that is, the frequency 'f' of his motion) to the walking pace of a person of average height is

[tex]\frac{V_2}{V_1}=1.10[/tex]

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A uniform disk with mass 43.9 kgkg and radius 0.280 mm is pivoted at its center about a horizontal, frictionless axle that is stationary. The disk is initially at rest, and then a constant force 29.0 NN is applied tangent to the rim of the disk. Part A What is the magnitude vv of the tangential velocity of a point on the rim of the disk after the disk has turned through 0.400 revolution

Answers

Answer:

1.36 m/s

Explanation:

I = ½mR²

τ = FR

α = τ/I = FR / (½mR²) = 2F/mR

a = Rα = 2F/m

s = θR

v² = u² + 2as

u = 0

v = √2as = √(2(2F/m)(θR)) = 2√(FθR/m)

v = 2√(29.0(0.400)(2π)(0.280) / 43.9) = 1.3636272...

what does displacement consists of

Answers

Answer:

The displacement of a body has two components: rigid-body displacement and deformation. A rigid-body displacement consists of a simultaneous translation and rotation of the body without changing its shape or size.

Explanation:


Which units are being recalled?

—-

Answers

Answer:

a c e f

Explanation:

Start with the last year then the month. to eliminate wrong choices

_____ is a distinct element found in Balinese Gamelan music in which a pair of gongs, one of them de-tuned, is played together, creating a sound similar to a tremolo.

its music btw

Answers

Answer:

best song ever will you follow me I will also follow you

A solid metal sphere of radius 3 m carries a total charge of -5.5 uc. What is the magnitude of the
electric field at a distance from the sphere's center of (a) 2.9 m and (b) 8 m? How would the answers
differ if the sphere was (c) a thin shell.
IN​

Answers

Answer:

2.9::: 5.87*10*3 N/C

8: 7.73 × 10 ^2  N/C

Explanation: https://study.com/academy/answer/a-solid-metal-sphere-of-radius-3-00-m-carries-a-total-charge-of-5-50-muc-what-is-the-magnitude-of-the-electric-field-at-each-of-the-following-distances-from-the-sphere-s-center-a-3-10-m-b-8-00-m.html

How many different ingredients will you need…

Answers

Answer:

11

Explanation:

hope this helps!!!!!

In the diagram, the crest of the wave is show by:
A
B
C
D

Answers

Answer:

D.

Explanation:

The crest of a wave refers to the highest point of a wave. This is illustrated by D.

Which was a major effect of Pope Leo III crowning Charlemagne emperor of the Romans ?

Answers

Answer:

The crowning of Charlemagne by Pope Leo III was significant in a number of ways. For Charlemagne, it was necessary because it encouraged to give him higher reliability. It gave him the rank of a dictator, giving him the only ruler in Europe west of the Byzantine emperor in Constantinople.

. Two charges, Q1 and Q2 , are separated by a certain distance R. If the magnitudes of the charges are halved, and their separation is also halved, then what happens to the electrical force between these charges

Answers

Answer: Magnitude of electrical force stays the same.

Explanation:

Equation:

[tex]F_{e} =k\frac{Q_{1}Qx_{2} }{r^{2} }[/tex]

Since the magnitude of each charge is halved.

and

the separation is halved.

[tex]F_{e} =k\frac{(.5Q_{1}*.5Q_{2} }{(.5r)^{2} }[/tex]

[tex]F_{e} =k\frac{.25*Q_{1}Qx_{2} }{.25*r^{2} }[/tex]

Cancel out .25 on the numerator and denominator. Leaving the original equation.

PleasePlease help me solve these articles with me

Answers

Ngl I lost brain cells tryna figure out what ur doing

The speed of a horse is 134 meters per second how long does it takes to travel a distance of 19,311?

Answers

Answer:

just need some focus

Explanation:

tan 13. The speed of a horse is 134 meters per second how long does it take to travel a distance of 19,311m? M+ tud V 134 14. You are walking down the block and see your neighbor's pitbull 30 meters away, out of the fence, starring at you. Suddenly, he starts running towards you at 20m/s. How long will it be before you're the pitbull's lunch?  V 15. A pendulum has a frequency of 2 Hz what is it's period. T = 1/2 16. You have just finished a 1600 mile trip, and it took you 16 hours. What was your average speed V = Ad At 17. You are flying from New York, NY to SanFrancisco California, a distance of 2582 miles, it takes 6.33hrs to complete the flight what was your average speed? give answer in m/s. V = Ad = At 3 of 6

Please help me. Im not good at physics​

Answers

Answer:

The answer is frictional force !

Answer:

4th option Friction

Explanation:

Friction always is there when an object is incline (sloping)

and here you can see the box is slopping down so frictional force is applied here

What is the author's MAIN purpose for including information about viruses? D to suggest that it could be dangerous for explorers to bring home life from other planets B to provide an example that illustrates the difficulty of defining life in some cases on Earth С to demonstrate the need for extra protective gear when explorers go into space D to highlight the differences between natural life and artificial life mixed in a lab Back Submit​

Answers

Answer:

B

Explanation:

Under normal circumstances: _________
a. Fetal Hb binds to oxygen more tightly than Mb binds.
b. Fetal Hb binds oxygen more tightly in the absence of 2,3-BPG.
c. Fetal Hb does not bind to oxygen.
d. Adult Hb has the lowest affinity for oxygen of the 3.
e. More than one of these statements is correct.

Answers

Answer:

Fetal Hb binds oxygen more tightly than adult Hb (not option a)

If a nucleus decays by successive b, a, a emissions, its mass number will Group of answer choices decrease by seven. decrease by two. decrease by four. decrease by eight. increase by four.

Answers

Answer:

The mass number will decrease by eight (8).

Explanation:

Given;

successive beta (b), alpha (a), alpha (a) emissions.

Generally, when a radioactive element emits a beta-particle (b), its mass number doesn't increase but its atomic number increases by 1 . [tex](^{0}_{-1}\beta )[/tex]

Also when a radioactive element emits an alpha-particle (a), its mass number decreases by 4, while its atomic number decrease by 2. [tex](^4_2\alpha)[/tex]

For the given question, a successive beta (b), alpha (a),  and alpha (a) emissions = (0) + (-4) + (-4) = -8

Thus, when a radioactive element emit a successive beta (b), alpha (a), alpha (a) particles, the mass number will decrease by eight (8).

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It takes Serina 0.68 hours to drive to school. Her route is 34 km long. What is Serina's average speed on her drive to school?

Answers

Speed = distance / time

Speed = 34 km / 0.68 hrs

Speed = 50 km/hr

according to the big bang theory, what did protons and neutrons form from?

Answers

Answer:

Explanation:

In the first moments after the Big Bang, the universe was extremely hot and dense. As the universe cooled, conditions became just right to give rise to the building blocks of matter – the quarks and electrons of which we are all made. A few millionths of a second later, quarks aggregated to produce protons and neutrons. Within minutes, these protons and neutrons combined into nuclei. As the universe continued to expand and cool, things began to happen more slowly. It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms. These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.

But stars and galaxies do not tell the whole story. Astronomical and physical calculations suggest that the visible universe is only a tiny amount (4%) of what the universe is actually made of. A very large fraction of the universe, in fact 26%, is made of an unknown type of matter called "dark matter". Unlike stars and galaxies, dark matter does not emit any light or electromagnetic radiation of any kind, so that we can detect it only through its gravitational effects.  

An even more mysterious form of energy called “dark energy” accounts for about 70% of the mass-energy content of the universe. Even less is known about it than dark matter. This idea stems from the observation that all galaxies seems to be receding from each other at an accelerating pace, implying that some invisible extra energy is at work.

Protons and neutrons formed from quarks in the early universe, a process driven by extremely high temperatures and energies.

In the early cosmos, quarks generated protons and neutrons, which form atomic nuclei, according to the Big Bang hypothesis. Quarks and gluons, which bond quarks, existed freely in a quark-gluon plasma state in the early cosmos due to extreme heat and energy.

Hadronization formed protons and neutrons from quarks as the cosmos cooled and expanded. Eventually, protons and neutrons formed atomic nuclei as the cosmos evolved. This key stage in the early universe's existence formed the basic particles that make up matter today.

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A particle moves along the x axis. In order to calculate the torque on the particle, you need to know:

a. the rotational inertia of the particle
b. the velocity of the particle
c. the mass of the particle
d. the kinetic energy of the particle
e. the point about which the torque is to be calculated

Answers

Answer:

e. the point about which the torque is to be calculated

Explanation:

torque is the product of a force and a distance

the point about which the torque is calculated is required to know the distance.

None of the other terms are relevant as they refer to mass or its equivalent, and velocity. Force is not mentioned in any of them.

A particle moves along the x-axis. In order to calculate the torque on the particle, you need to know the point about which the torque is to be calculated. Therefore, option E is correct.

What is torque ?

The rotating equivalent of force is torque. Depending on the subject of study, it is also known as the moment, moment of force, rotating force, or turning effect. It illustrates how a force can cause a change in the body's rotational motion.

Ancient Romans gave these necklaces the term "torque" by describing them as twisted and spiral screw-shaped using the Latin word "torquere," which also means "twisting" and "turning."

It's critical to realize that torque, which has to do with your motor's power in terms of rotational force, is not the same thing as speed. Find a motor with a top speed if you require more motor speed, and a motor with a motor torque that is maximized if you need more rotational force.

Thus, option E is correct.

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Match the following properties to the type of wave.

Answers

Answer:

hi there

Explanation:

1 - III

2- 1

3-1

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PLz mark me as a BRAINLIST

Explanation:

1 . 3

2. 1

3. 2

I hope it is helpful to you.

The radius of the wheel is 40cm and the radius of the

axle is 0.1 metre in a wheel and

axle. If a load of 1200N is overcome up to 4m by applying

an effort of 400N, calculate:

i. mechanical advantage ii. velocity ratio iii. efficiency

iv. output work v. input work ​

Answers

Answer:

M.A = load/ effort

1200N/400N

= 3

velocity ratio= radius of wheel/radius of Axle

40cm/10cm

=4

efficiency= 3/4*100

75%

i. mechanical advantage =  3

ii. velocity ratio =  4

iii. efficiency =  75%

iv. output work  = 4800 J

v. input work =  64 J ​

What is mechanical advantage?

Mechanical advantages allows humans to perform tasks much easier in terms of the force they need to apply, but must always obey the conservation of energy.

i) mechanical advantage  = Resistance force / Effort force

                                      = 1200N / 400 N

                                      = 3

ii) velocity ratio = velocity of effort / velocity of load

                         = distance moved by effort / distance moved by load

                         = 2π R (radius of wheel) / 2π r ( radius of axle )

                         = R / r = 40 cm/ 10 cm = 4

iii) efficiency =  ?

Mechanical advantage   = efficiency * velocity ratio

efficiency  =( Mechanical advantage /    velocity ratio) *100

                = (3/ 4) * 100  

                = 75%

iv) output work = Force to lift the object * distance

                         = 1200 * 4 = 4800 J

v) efficiency = output work / input work

             75   =  4800 J / input work

input work = 64 J

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a standard bathroom scale is placed on an elevator. A 34 kg boy enters the elevator on the first floor and steps on the scale. What will the scale read (in newtons) when the elevator begins to accelerate upward at 0.4 m/s2

Answers

Answer:F = 255 N

Explanation:

It is given that,

Mass of the boy, m = 25 kg

Acceleration of the elevator,  

The elevator is accelerating in upward direction. The net force acting on the boy is given by :

g is the acceleration due to gravity

F = 255 N

The scale reading is 255 N as it begins to accelerate upward. hence, this is the required solution.

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