how much power is needed to lift a box with a force of 780 newtons over a distance of 2 meters in 45 seconds

[tex]\\ \sf\Rrightarrow K.E=\dfrac{1}{2}mv^2[/tex]

[tex]\\ \sf\Rrightarrow K.E=\dfrac{1}{2}(40)(1)^2[/tex]

[tex]\\ \sf\Rrightarrow K.E=20J[/tex]

[tex]\\ \sf\Rrightarrow K.E=\dfrac{1}{2}(80)(1)^2[/tex]

[tex]\\ \sf\Rrightarrow K.E=40J[/tex]

Photovoltaic panels are used to produce alternating current using sunlight. It uses solar cells which are photoactive and produce a photoelectric effect and thereby a potential is created.

When photons from the light energy is hit on a metallic surface the photon collides with the electrons of the metals and electrons are ejected from the metal surface. This phenomenon is called photoelectric effect.

In a solar photovoltaic panel, photovoltaic cells layers of semi-conducting materials, such as silicon, are sandwiched photovoltaic cells. When photons from sunshine strike each layer, its unique electronic properties energise and produce an electric field.

The current required to generate electricity is produced through what is known as the photoelectric effect. Electricity produced by solar panels is in the direct current form. This is then transformed into an alternating current by passing via an inverter.

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Answer:

friction. or gravity both ofbthem .....................

..

So acceleration of the bike which started from rest, reaches at speed of 7.10 m/s by travelling distance 35.4 m will be 0.712 m/ sec^2.

Answer:

When did humans learn that the Earth is not the center of the universe?

Answer

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4 Answers

Asked in 3 Spaces





Science - Next Generation

Alexander Somm

, Consultant, Investor Relations at Novelpharm AG (2015-present)

Answered Oct 16

What, it isn’t?!

Sorry, I had to.

As far as I have read and understood, the Sumerians and later the Babylonians both had astronomical calendars that already differentiated planets and stars. Earth was not the center to them, the Sun likely was. That was around 2,200 - 1,600 BC.

After that, Greek philosopher Aristarchus of Samos (310 - 230 BC) was the first (recorded) to have believed the solar system was organized around the Sun, rather than the Earth. His heliocentric model was unpopular during Aristarchus’ lifetime, although it would inspire astronomers centuries later, such as Copernicus and Galileo.

Now, there are numerous archeological findings (cave paintings) and studies, that all suggest an understanding of complex astronomy in prehistoric times dating back as far as 40,000 years. This also explains how early, prehistoric migrants may have navigated the seas.

Explanation:

hope it helps

have a good day

Answer:

[tex]\boxed {\boxed {\sf 4 \ Newtons}}}[/tex]

Explanation:

Work is energy transferred when an object is moved. It is the product of force and distance.

[tex]W= F*d[/tex]

John did 3.2 Joules of work or 3.2 Newton meters of work (the units are equivalent). The window shade was lowered a distance of 0.8 meters.

Substitute the values into the formula.

[tex]3.2 \ N *m = F * 0.8 \ m[/tex]

We are solving for the force, so we must isolate the variable F. It is being multiplied by 0.8 meters. The inverse operation of multiplication is division, so divide both sides of the equation by 0.8 m.

[tex]\frac {3.2 \ N*m}{0.8 \ m}= \frac{ F* 0.8 \ m}{0.8 \ m}[/tex]

The units of meters cancel.

[tex]\frac {3.2 \ N}{0.8 }=F[/tex]

[tex]4 \ N = F[/tex]

John must exert 4 Newtons of force.

Answer:

i can

Explanation:

i know what's the answer

Answer:

Since there is no external force, there is no change (movement) in the center of mass. Internally, the center of mass might change position, but the external result is still zero net velocity.

The net recoil velocity must be zero.

Explanation:

it's mean hI small little cute baby girl ...

Answer:

We can determine the age of the Earth and the rocks found on Earth with techniques such as measuring ice cores and digging and analysing fossils.

Explanation:

Hopefully this helped!

Answer:

C.Plane mirror this is the answer of this question.

None of the above. That is option D.

A spherical mirror is defined as a mirror that has a surface that reflects curved rays. It is also called a curved mirror.

Types of spherical mirror include:

Example of concave mirror are Torch lights and automobile headlights.

Example of convex mirror is the magnifying glasses and telescopes.

Therefore, concave, convex and plane mirrors are all examples of a spherical mirror.

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Answer:

Asteroids smaller than planets and meteroids are small piece of an asteroid burns up upon enetering Earths atmosphere

Hi there!

a.

The equation for centripetal acceleration is as follows:

[tex]\large\boxed{a_c = \frac{v^2}{r}}}[/tex]

Plug in the given values to solve:

[tex]\large\boxed{a_c = \frac{(65)^2}{75} = 56.33 m/s^2}[/tex]

b.

According to Newton's Second Law:

[tex]\large\boxed{\Sigma F = ma}}[/tex]

The acceleration is v²/r, so the net force is:

[tex]\large\boxed{\Sigma F = m(\frac{v^2}{r})}}[/tex]

Multiply by the given mass:

[tex]\large\boxed{\Sigma F = 700(56.33) = 39433.33 N}}[/tex]

c.

There is NO net force in the vertical direction since the object is NOT accelerating in the vertical direction (normal force and weight cancel).

Thus, the ONLY net force experienced by the object is in the horizontal direction and is EQUAL to the centripetal force.

Answer:

i think wave lengh not 100% sure tho

If the energy of the mechanical wave will increase or decrease, then the wavelength will also change accordingly. Hence, option A is correct.

The distance between two identical locations (adjacent crests) in successive cycles is known as the wavelength, and it is used to describe waveform signals that are transmitted over wires or into space. Typically, in wireless systems, this length is specified in meters (m), centimeters (cm), or millimeters (mm). The wavelength is more frequently described in nanometers (nm), which are units of 10⁻⁹ m, or angstroms, which are units of 10⁻¹⁰ m, for infrared (IR), visible light (UV), and gamma radiation.

Frequency, which is defined as the number of wave cycles per second, and wavelength have an inverse relationship. The wavelength of a signal decreases with increasing frequency, or we can say that wavelength and refractive index are inversely proportional to each other.

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From Newton's second law of motion, the average force on the ball by the racket is 98 Newtons. The correct answer is option C

Given that a 0.07 kg tennis ball, initially at rest, leaves a racket with a speed of 56 m/s. And the time for contact with the racket is 0.04 s, that is,

mass m = 0.07 kg

velocity v = 56 m/s

time t = 0.04 s

force f = ?

To calculate the average force on the ball by the racket, let us apply Newton's second law of motion.

Impulse = change in momentum

ft = mv

Substitute all the parameters into the equation above

0.04f = 0.07 x 56

make f the subject of the formula

f = 3.92 / 0.04

f = 98 N

Therefore, the average force on the ball by the racket is 98 Newtons. The correct answer is option C

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The average force on the ball by the racket is 98 N. The correct option is the third option - 98 N

From the question, we are to determine the average force on the ball by the racket.

From the formula,

[tex]F = \frac{mv}{t}[/tex]

Where F is the force

m is the mass

v is the velocity

and t is the time

From the given information

m = 0.07 kg

v = 56 m/s

t = 0.04 s

Putting the parameters into the formula,

we get

[tex]F = \frac{0.07 \times 56}{0.04}[/tex]

[tex]F = \frac{3.92}{0.04}[/tex]

F = 98 N

Hence, the average force on the ball by the racket is 98 N. The correct option is the third option - 98 N

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Inside the bar magnet, the magnetic field points from north to south. Statement A is correct.

Magnetic Field:

It is defined as a vector field or the influence of the magnet on the electric current, charges and ferromagnetic substance.

The strength of magnetic field is depends up on the numbers of magnetic field lines per unit area.

Therefore, inside the bar magnet, the magnetic field points from north to south.

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Answer:b

Explanation:

1. • Here, force of gravity on the block = 20 N.

• Therefore, the normal force will also be the same, i.e., 20 N [According to Newton's Third Law, on every action, there is an equal and opposite reaction]

• The coefficient

[tex] u_{k} = 0.4[/tex]

• Force of friction =

[tex]u_{k} \times \: normal \: \: \: force \\ = 0.4 \times 20N \\ = 8N[/tex]

• Hence, the force of sliding friction between the block and the ground is 8 N.

• So, it is option c. 8 N

2. The answer is option d. continue in the same direction with no change in speed.

We know, force = mass × acceleration. When force is 0, then acceleration will also be 0 since mass cannot be 0. So, there will be no change in speed.

3. It is option b. force that is required to give a one kilogram object the acceleration of 1 m/s^2.

Newton is the SI unit of force. As mentioned earlier, force = mass × acceleration. The SI unit of mass and acceleration is Kg and m/s^2 respectively.

So, 1 N = 1 Kg × 1 m/s^2.

4. It is d. not zero.

Acceleration is the change in speed. So, if the force is zero, then acceleration will not occur.

5. Force = 2 N

Acceleration of the object A = 2 m/s^2.

Acceleration of the object B = 1 m/s^2.

Therefore, mass of the object A = 2 N ÷ 2 m/s^2 = 1 Kg

And, mass of the object B = 2 N ÷ 1 m/s^2 = 2 Kg

So, the mass of object B is greater than that of object A.

Hence, the answer is option c. Object B has more mass.

Hope you could get an idea from here.

Doubt clarification - use comment section.

Momentum is conserved, so

(2 kg) (50 m/s) + (4 kg) (-25 m/s) = (2 kg) v₁' + (4 kg) v₂'

where v₁' and v₂' are the velocities of the two blocks after the collision. Simplifying this gives

100 kg•m/s - 100 kg•m/s = (2 kg) v₁' + (4 kg) v₂'

0 = (2 kg) v₁' + (4 kg) v₂'

v₁' = -2v₂'

Energy is also conserved, so

1/2 (2 kg) (50 m/s)² + 1/2 (4 kg) (-25 m/s)² = 1/2 (2 kg) (v₁')² + 1/2 (4 kg) (v₂')²

Simplifying yields

2500 J + 1250 J = (1 kg) (v₁')² + (2 kg) (v₂')²

3750 J = (1 kg) (v₁')² + (2 kg) (v₂')²

Substitute v₁' = -2v₂' and solve for v₂' :

3750 J = (1 kg) (-2v₂')² + (2 kg) (v₂')²

3750 J = (6 kg) (v₂')²

(v₂')² = 625 J/kg = 625 m²/s²

v₂' = 25 m/s

Then the first block has final velocity

v₁' = -2 (25 m/s)

v₁' = -50 m/s

Your speed when your car hits a fixed object is 60 mph.

The given parameters:

Relative velocity tells us how fast we are traveling from a fixed point or reference point.

Thus, we can conclude that your speed when your car hits a fixed object is 60 mph.

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The specific heat capacity of tungsten given the data from the question is 0.17 J/gºC

Mass of tungsten (M) = 100 g

Temperature of tungsten (T) = 100 °C

Mass of water (Mᵥᵥ) = 200 g

Temperature warm water (Tᵥᵥ) = 20 °C

Specific heat capacity of the water (Cᵥᵥ) = 4.184 J/gºC

Equilibrium temperature (Tₑ) = 21.6 °C

Specific heat capacity of tungsten (C) = ?

Heat loss = Heat gain

MC(T – Tₑ) = MᵥᵥCᵥᵥ(Tₑ – Tᵥᵥ)

100 × C × (100 – 21.6) = 200 × 4.184(21.6 – 20)

100 × C × 78.4 = 1338.88

Divide both sides by 100 × 78.4

C = 1338.88 / (100 × 78.4 )

C = 0.17 J/gºC

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1) Inicialmente, debemos determinar la velocidad de las ondas sonoras a través del agua ([tex]v[/tex]), en metros por segundo:

[tex]v = \sqrt{\frac{K}{\rho} }[/tex] (1)

Donde:

Si sabemos que [tex]\rho = 1\times 10^{3}\,\frac{kg}{m^{3}}[/tex] y [tex]K = 2,16\times 10^{9}\,\frac{N}{m^{2}}[/tex], entonces la velocidad de las ondas sonoras es:

[tex]v = \sqrt{\frac{2,16\times 10^{9}\,\frac{N}{m^{2}}}{1\times 10^{3}\,\frac{kg}{m^{3}} } }[/tex]

[tex]v\approx 1469,694\,\frac{m}{s}[/tex]

La velocidad de las ondas sonoras es aproximadamente 1469,694 metros por segundo.

2) Luego, determinamos la longitud de onda ([tex]\lambda[/tex]), en metros, mediante la siguiente fórmula:

[tex]\lambda = \frac{v}{f}[/tex] (2)

Donde [tex]f[/tex] es la frecuencia de las ondas sonoras, en hertz.

Si sabemos que [tex]v\approx 1469,694\,\frac{m}{s}[/tex] y [tex]f = 1000\,hz[/tex], entonces la longitud de onda de las ondas sonoras es:

[tex]\lambda = \frac{1469,694\,\frac{m}{s} }{1000\,hz}[/tex]

[tex]\lambda = 1,470\,m[/tex]

La longitud de onda de las ondas sonoras es 1,470 metros.

Para aprender más sobre las ondas sonoras, invitamos a ver esta pregunta verificada: https://brainly.com/question/1070238

The Earth's orbital period change is A: It would increase by 0.15 years

Using Kepler's third law which states that the square of the orbital period of the planet is directly proportional to the cube of its distance from the sun.

So, T² ∝ R³

T'²/T² = R'³/R³ where

So, making T' subject of the formula, we have

T' = [√(R'/R)³]T

T' = [√(1.1 AU/1 AU)³] × 1 year

T' = [√(1.1)³] × 1 year

T' = √1.331 × 1 year

T' = 1.15 × 1 year

T' = 1.15 years.

So, the change in the Earth's orbital period ΔT = T' - T

= 1.15 years - 1 year

= 0.15 years

Since this is positive, the orbital period increases by 0.15 years.

So, the Earth's orbital period change is A: It would increase by 0.15 years

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Answer:

500 J.

Explanation:

Work done = force * distance

= 25 * 20

= 500 Joules.

Answer:

100 J work was done.

Hope you could get an idea from here.

Doubt clarification - use comment section.

Answer: the gravitational attraction on the Moon is much less than it is here on Earth, and a person weighs less on the Moon.

Explanation:

Answer:

the acceleration of the trolley is the acceleration of the trolley is 0.75 m/s^-2

Explanation:

friction force between the block and the trolley

= 1×0.3×9.8

= 2.94 N

(F = ma)

the acceleration of the trolley

= friction force/mass

= 2.94/4

= 0.735 m/s^-2

= 0.75 m/s^-2

The acceleration of the trolley will be 0.75 m/s².Acceleration is the ratio of the force to the mass.

It is a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. its unit is Newton (N).

Mathematically it is defined as the product of the coefficient of friction and normal reaction.

The friction force between the block and the trolley is found as;

[tex]\rm F_f = \mu N \\\\ \rm F_f = \mu \times mg \\\\ \rm F_f = 0.30 \times 1 \timess 9.81 \\\\ \rm F_f= 2.94 \ N[/tex]

Mechanical force is equal to the product of the mass and the acceleration which is equal to the frictional force;

[tex]\rm F_f =F=ma \\\\ \rm a = \frac{F}{m} \\\\ \rm a = \frac{2.94}{4} \\\\ a=0.735 \ ms^{-2}[/tex]

Hence the acceleration of the trolley will be 0.75 m/s².Acceleration is the ratio of the force to the mass.

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Vertical component = 40 m/s x sin(60) = 34.6 m/s

Answer: b. 34.6 m/s