What was the initial velocity of a rock throw upwards if the velocity after 8 s is 90m/s?

Answer:

4Al + 3O2 + heat ------> 2Al2O3

Explanation:

It is endothermic reaction.

Explanation:

Transparent objects do not form shadows. The light passes completely from the transparent objects thus these objects will not form shadow. ... In such objects, the light gets refracted thus, such objects forms shadow. The refraction is also the reason why we can see such objects.

Explanation:

cause it pass the light coming from the source of light

Question:

Find the magnitude and direction of the electric field at points that are at the following distances from the center of the aluminum rod:

(a) 0.5 cm, (b) 1.5 cm, (c) 2.5 cm, (d) 3.5 cm, (e) 7.0 cm

Answer:

(a) 0

(b) 4.795 N/C

(c) 2.877 N/C

(d) 2.055 N/C

(e) 1.027 N/C

Explanation:

The given parameters are;

The inner radius of the copper = 2 cm

The outer radius of the copper - 3 cm

The radius of the aluminum rod, r = 1 cm

The radius of the aluminum rod = 4 pC/m

a) The charge at the 0.5 cm from the center of the aluminum rod, E = 0

There is no charge inside the rod given that the aluminum road is a conductor of electricity, having all the charge on its surface

b) At 1.5 cm, we have;

[tex]E = \dfrac{2 \cdot \lambda}{4 \cdot \pi \cdot r \cdot \epsilon_0}[/tex]

Where;

[tex]\dfrac{ \lambda}{4 \cdot \pi \cdot \epsilon_0} = 8.99 \times 10^9 \times 4 \times 10^{-12}[/tex]

r = 1.5 cm = 0.015 m

∴ E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.015 ≈ 4.795

The magnitude of the electric field, E = 4.795 N/C

The direction of the charge depends on the charge sign on the rod

c) At 2.5 cm, we have;

r = 2.5 cm = 0.025 m

E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.025 ≈ 2.877

The magnitude of the electric field, E ≈ 2.877 N/C

d) At r = 3.5 cm, we have;

r = 3.5 cm =  0.035 m

E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.035 ≈ 2.055

The magnitude of the electric field, E ≈ 2.055 N/C

e) At

r = 7.0 cm = 0.070 m

E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.07 ≈ 1.027

The magnitude of the electric field, E ≈ 1.027 N/C

Initial velocity of car is 0.

Final velocity of car is 36 km/h.

Time taken to attain final speed is 2 minutes.

What is the acceleration of car ?

v = u + at

First change the final velocity from km/h to m/s and also time to seconds.

[ To change km/h to m/s multiply by 5/18 ]

➙ Final velocity = 36(5/18) = 10 m/s.

[ 1 minutes = 60 seconds ]

➙ 2 minutes = 2(60) = 120 seconds.

Now, we have

v = 10 m/s.

u = 0 m/s.

t = 120 s.

Hence, the acceleration of car is 0.083 m/s².

➟ The rate of change of velocity is called acceleration. It is denoted by a.

➟ The velocity at which motion starts is termed as initial velocity. It is denote by u.

➟ The last velocity of an object after a period of time. It is denoted by v.

[tex]\boxed{\large{\bold{\blue{ANSWER~:) }}}}[/tex]

By 1st Equation of motion

we know that,

[tex]\boxed{\large{\sf{v \: = u \: + a \: t}}}[/tex]

according to the question,

[tex]10 = 0 + a \times 120\\\\a \: = \frac{10}{120}\\\\a \: = \frac{1}{12}\\\\a=0.083\: m {s}^{ - 2}[/tex]

Therefore,

Acceleration of the car is 0.083 ms^-2

Answer:

R = 0.2 Ω

Explanation:

Para aplicar el concepto de resistencia de un conductor electrico, consideramos la siguiente formula:

R = ρ . l / S

Donde l es la longitud del conductor

S la superficie

y ρ el coeficiente de resistividad

Primero necestiamos hacer ciertas conversiones:

ρ = 0.10 ×10⁻⁶ (Ω . m²/m)

S = 2 mm² → 2 ×10⁻⁶ m²

R = 0.10 ×10⁻⁶ (Ω . m²/m) . 4m / 2 ×10⁻⁶ m²

Dentro de la formula simplificamos las unidades, los metros de ρ con la longitud y ambos m². De esa forma la unidad de R queda en Ω (ohmios).

Resolvemos:

R = 0.10 ×10⁻⁶ Ω . 4 / 2 ×10⁻⁶

R = 0.2 Ω

Answer:

truuuuuuuuuuuuuuuuuuuuuuuuujuuuuuuuur

Answer:

true

Explanation:

I took a test this year and I know the answer

Answer:

Explanation:

2) From F=ma

Force =15×40=600N or kgm/s2

3)From the same equation making acceleration the subject of the formula will give

a=f÷m

=24÷4=6m/s2

4)m=f÷a

=45÷15=3kg

Answer:

hope it is helpful to you ☺️☺️✌️

Answer:

Resistance in pencil sharpener = 12 ohms

Explanation:

Given:

Voltage in pencil sharpener = 6 volts

Current in pencil sharpener = 0.5 amps

Find:

Resistance in pencil sharpener

Computation:

Resistance = Voltage / Current

Resistance in pencil sharpener = Voltage in pencil sharpener / Current in pencil sharpener

Resistance in pencil sharpener = 6 / 0.5

Resistance in pencil sharpener = 12 ohms

The question is: Two masses with values ​​of 8kg and 12kg each are separated by a distance of 1m. Determine the force of gravitational attraction between them if compared with the value of their weights. What is this value?

Answer: The force of gravitational attraction between them if compared with the value of their weights is [tex]640.704 \times 10^{-11} N[/tex].

Explanation:

Given: [tex]m_{1}[/tex] = 8 kg,       [tex]m_{2}[/tex] = 12 kg

Distance = 1 m

Formula used is as follows.

[tex]F = \frac{G \times m_{1} \times m_{2}}{r^{2}}[/tex]

where,

F = force of gravitational attraction

G = gravitational constant = [tex]6.674 \times 10^{-11} N m^{2}/kg^{2}[/tex]

[tex]m_{1}[/tex] = mass of object 1

[tex]m_{2}[/tex] = mass of object 2

r = distance between the centers of these two objects

Substitute the values into above formula as follows.

[tex]F = \frac{G \times m_{1} \times m_{2}}{r^{2}}\\= \frac{6.674 \times 10^{-11} Nm^{2}/kg^{2} \times 8 kg \times 12 kg}{(1 m)^{2}}\\= 640.704 \times 10^{-11} N[/tex]

Thus, we can conclude that the force of gravitational attraction between them if compared with the value of their weights is [tex]640.704 \times 10^{-11} N[/tex].

Answer:

Alpha decay

Explanation:

Answer:

C

Explanation:

Alpha Decay

Answer: A Graduated Cylinder or A Beaker ?

Explanation:

Answer:

Momentum = 4455 Ns

Explanation:

Given the following data;

Force = 450 N

Time = 9.9 seconds

To find the momentum;

According to Newton's second law of motion in terms of momentum states that the net force acting on an object is equal to change in momentum divided by time.

Mathematically, it is given by the formula;

Net Force = change in momentum/time

Momentum = force * time

Substituting into the formula, we have;

Momentum = 450 * 9.9

Momentum = 4455 Ns

Answer: you ever get the awnser?

Explanation:

Answer: 0.12 g

Explanation: I got it right on the quiz.

Answer:

(i) Please find attached the required velocity time graphs plotted with MS Excel

(ii) The velocity of vehicle A at the 18th second = 20 m/s

The velocity of vehicle B at the 18th second = 0 m/s

(iii) The distance between the two vehicles at the moment in (ii) above is 60 meters

Explanation:

The given parameters of the motion of vehicles A and B are;

The acceleration of vehicles A and B = Uniform acceleration starting from rest

The maximum velocity attained by vehicle A = 30 m/s

The time it takes vehicle A to attain maximum velocity = 10 s

The maximum velocity attained by vehicle B = 30 m/s

The time it takes vehicle B to attain maximum velocity = The time it takes vehicle A to attain maximum velocity = 10 s

The time duration vehicle A maintains its maximum velocity = 6 s

The time duration vehicle B maintains its maximum velocity = 4 s

(i) From the question, we get the following table;

[tex]\begin{array}{ccc}Time &V_A&V_B\\0&0&0\\10&30&40\\14&30&40\\16&30&20\\18&20&0\\22&0&\end{array}[/tex]

From the above table the velocity time graphs of vehicles A and B is created with MS Excel and can included here

(ii) The velocity of vehicle A at the start = 0 m/s

After accelerating for 10 seconds, the velocity of vehicle A = The maximum velocity of vehicle A = 30 m/s

The maximum velocity is maintained for 6 seconds which gives;

At 10 s + 6 s = 16 s, the velocity of vehicle A = 30 m/s

The time it takes vehicle A to decelerate to rest = 6 s

The deceleration of vehicle A, [tex]a_A[/tex] = (30 m/s - 0 m/s)/(6 s) = 5 m/s²

Therefore, we get;

v = u - [tex]a_A[/tex]·t

At the 18th second, the deceleration time, t = 18 s - 16 s = 2 s

u = 30 m/s

∴ v₁₈ = 30 - 5 × 2 = 20

The velocity of vehicle A at the 18th second, [tex]V_{18A}[/tex] = 20 m/s

For vehicle B, we have;

At the 14th second, the velocity of vehicle B = 40 m/s

Vehicle B decelerates to rest in, t = 4 s

The deceleration of vehicle B, [tex]a_B[/tex] = (40 m/s - 0 m/s)/(4 s) = 10 m/s²

For vehicle B, at the 18th second, t = 18 s - 14 s = 4 s

∴ [tex]v_{18B}[/tex] = 40 m/s - 10 m/s² × 4 s = 0 m/s

The velocity of the vehicle B at 18th second, [tex]v_{18B}[/tex] = 0 m/s

(iii) The distance covered by vehicle A up to the 18th second is given by the area under the velocity-time graph as follows;

The area triangle A₁ = (1/2) × 10 × 30 = 150

Area of rectangle, A₂ = 6 × 30 = 180

Area of trapezoid, A₃ = (1/2) × (30 + 20) × 2 = 50

The distance covered in the 18th second by vehicle [tex]S_A[/tex] = A₁ + A₂ + A₃

∴ [tex]S_A[/tex] = 150 + 180 + 50 = 380

The distance covered in the 18th second by vehicle [tex]S_A[/tex] = 380 m

The distance covered by the vehicle B in the 18th second is given by the area under the velocity time graph of vehicle B as follows;

Area of trapezoid, A₅ = (1/2) × (18 + 4) × 40 = 440

The distance covered by the trapezoid, [tex]S_B[/tex] = 440 m

The distance of the two vehicles apart at the 18t second, [tex]S_{AB}[/tex] = [tex]S_B[/tex] - [tex]S_A[/tex]

∴ [tex]S_{AB}[/tex] = 440 m - 380 m = 60 m

The distance of the two vehicles from one another at the 18th second, [tex]S_{AB}[/tex] = 60 m.

Answer:

c and a

Explanation:

ape x

Answer:

The average number of calories needed daily represents the average quantity of calories eliminated by human body due to metabolism and must be compensated by eating and drinking.

The amount of calories contained in the food we eat every day must represent the amount of calories eliminated by the body in that time to have a steady weight.

Explanation:

The average number of calories needed daily represents the average quantity of calories eliminated by human body due to metabolism and must be compensated by eating and drinking. If total quantity of calories in the food we consume every day is higher that the average number of calories needed daily, then weight increases by fat accumulation.

Answer:

Explanation:

This is a simple F = ma equation. We have the mass and we have the acceleration, so

F = 1298(17) and

F = 22066 which rounds correctly to

F = 22000N

The magnitude of the net force of object with a mass of 1298 kg is accelerating at a rate of 17 m/s² is 22066N

HOW TO CALCULATE NET FORCE:

Learn more at: https://brainly.com/question/23245710?referrer=searchResults

Answer: D. ➡️⬅️

Explanation: I just knew the answer ;)

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When light strikes a black surface, it is reflected by the surface and

nothing is absorbed    This would be False because black absorbs the light not reflect

Mirrors are used in telescopes because they have the ability to reflect

True? Telescopes designed with mirrors avoid the problems of refracting telescopes. Because the light is reflected from the front surface only, flaws and bubbles within the glass do not affect the path of the light

Transmission in the passing of light through some materials​

False? Some materials allow much of the light that falls on them to be transmitted through the material without being reflected. Materials that allow the transmission of light waves through them are called optically transparent. ... Materials which do not allow the transmission of any light wave frequencies are called opaque.

Answer:

do you have the answer?

Explanation:

if so whats the answer?

Answer:

Sí se puede aplicar el Principio de Conservación de la Energía Mécanica siempre y cuando se considere los efectos de pérdida de energía a causa del rozamiento, de lo contrario, no se cumpliría el requisito de conservación derivado del citado principio de conservación.  

Explanation:

Consideremos que el cuerpo representa nuestro sistema de estudio, el cual se desplaza por una carretera y experimenta rozamiento, significando cambios en la energía cinética y potencial gravitacional. La presencia de rozamiento indica una disipación de la energía del cuerpo, cuya energía mecánica total disminuye, significando un sistema no conservativo.

Sí se puede aplicar el Principio de Conservación de la Energía Mécanica siempre y cuando se considere los efectos de pérdida de energía a causa del rozamiento, de lo contrario, no se cumpliría el requisito de conservación derivado del citado principio de conservación.  

Answer:

it depends on a person's own weight

Answer:

The gravity is roughly the same. The inverse square law applies to gravity and that means that being 60 miles above Earth is about the same as being on Earth. The thing is, they are going really fast in an orbit and thus falling around the Earth. The weightlessness comes from a sort of cancellation of gravity pulling them down and their going perpendicular to that force. The forces are cancelling and making them relatively “weightless”. It’s not really weightlessness but just an equilibrium reached between the two accelerations of gravity and their motion against the pull of the Earth.

Explanation:

Answer:

They don’t ‘represent’ anything, they are properties of the wave.

Depending on the type of wave, we experience them as various phenomena. For example, with a sound wave we experience frequency (or wavelength, which is just another way to describe the same property) as the pitch of the sound. We experience amplitude as the loudness of the sound, although due to the characteristics of the ear, frequency also effects perceived loudness.

If the wave is a light wave, we experience the frequency (wavelength) as the colour of the light, and the amplitude as the brightness of the light.

For many waves, we don’t perceive them at all (e.g. radio waves).

For ocean waves, frequency is the time for each peak or trough to reach us, and amplitude is how tall the wave is.

Answer:

conductor

Does not easily transfer electricity

Answer:

Gravity

Explanation:

It is gravity because the sun's gravity pulls all the planets towards itself and keeps the planets in the sun's orbit

Answer:

Acceleration is the name we give to any process where the velocity changes. Since velocity is a speed and a direction, there are only two ways for you to accelerate: change your speed or change your direction—or change both.

Answer:

The voltage across light bulb 1 and light bulb 2 is the the same i.e V

Explanation:

In a parallel circuit, the Voltage is same across all the components of the circuit and the current flowing through each component is added to get the total current across the circuit.

Let us say, the voltage across the circuit is V. The voltage across light bulb 1 and light bulb 2 is the the same i.e V