Simplifying the given expressions below,which of the following will give a negative result?
A.-19 + 0
B.-8 (-12)
C.26 -4
D.-10 - (-15)​

When two pith balls are charged by contact with a plastic rod that has been rubbed by cat fur, they will acquire opposite charges.

One pith ball will have a positive charge, while the other pith ball will have a negative charge.

When the plastic rod is rubbed by cat fur, it gains electrons from the fur, giving it a negative charge. These excess electrons are then transferred to the pith balls upon contact.

The transfer of electrons results in one pith ball gaining extra electrons, giving it a negative charge, while the other pith ball loses electrons, leaving it with a positive charge.

Therefore, the pith balls acquire opposite charges, one positive and one negative, due to the transfer of electrons from the charged plastic rod.

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There is a gravitational force between the Moon and the Earth, that tries to pull the Moon toward the latter. This constant tug on the Moon as it moves around the Earth is called a "centripetal" force.

gravitational force:

This force is balanced by the "centrifugal" force, that pulls on the Earth and keeps the moon in motion. The Moon orbits Earth, and it travels in a circle around it. There is a force between Earth and the Moon called gravity. Gravity causes larger objects to pull smaller ones towards them. Earth is larger than the Moon, which is why it pulls on the Moon. At the same time, the Sun is pulling on Earth. The Sun is larger than Earth. The balance between these two pulls is what keeps the Moon in orbit around Earth. As the Moon orbits the Earth, it experiences a gravitational force. This force acts as a centripetal force, keeping the Moon in its circular path. If this force were to disappear, the Moon would travel in a straight line, moving away from Earth. At the same time, Earth is being pulled by the Sun, which is why it experiences a centrifugal force. The balance between these two forces keeps the Moon in orbit around Earth.

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Both spheres would gravitationally attract a third sphere just like two charges of the same sign would attract a third charge of the opposite sign.

A sphere is symmetrical, round in shape. It is a three dimensional solid, that has all its surface points at equal distances from the center. It has surface area and volume based on its radius.

A sphere can be constructed as the surface formed by rotating a circle about any of its diameters; this is essentially the traditional definition of a sphere as given in Euclid's Elements. Since a circle is a special type of ellipse, a sphere is a special type of ellipsoid of revolution.

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If a book is drops from a height of 1.4 m, then the speed with which book hits the ground is 5.2 m/s.

Given,

Initial velocity = 0m/s

Height = h = 1.4m

Acceleration due to gravity = 9.8 m/s2.

This can be calculated by using third equation of motion,

v2 - u2 = 2gh

where,

v is the final velocity

u is the initial velocity

h is the height

and g is the acceleration due to gravity.

By substituting all the values, we get

v2 = 2 × 1.4 × 9.8

v2 = 27.44

v = 5.2 m/s

Thus, we concluded that if a book is drops

from a height of 1.4 m, then the speed with which book hits the ground is 5.2 m/s.

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Answer:

C

Explanation:

There is a decrease in temperature and daylight and plants produce less food.

Please mark brainliest!!

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Answer:

5.775 m/s

Explanation:

radial acceleration = velocity / radius

=> velocity = radial acceleration * radius

=> v = 3.5 * 1.65 = 5.775 (m/s)

The stresses acting on the surfaces of haulage excavated in an orthotropic rock mass is obtained.

Major and minor stresses act on the surfaces of excavations. Let's calculate the stresses acting on the surfaces of haulage excavated in an orthotropic rock mass given the following parameters acting at a point around the peripheral of the excavation. Major and minor stresses acting on the surfaces of excavations are given by the following equation:

σ1 = ½ [(σxx + σyy) + √[(σxx – σyy)² + 4σxy²]]σ2 = ½ [(σxx + σyy) – √[(σxx – σyy)² + 4σxy²]]σ3 = σzz

Here,

σ1 is the major stress,

σ2 is the minor stress,

σ3 is the axial stress,

σxx is the stress along the x-axis,

σyy is the stress along the y-axis,

σzz is the stress along the z-axis,

σxy is the shear stress in the xy plane,

σyz is the shear stress in the yz plane,

σzx is the shear stress in the zx plane,

and ε is the strain tensor acting at a point.

We have,E1 = 2.5E2 = 2E3 = 2.5V21 = 0.2V31 = 0.15V32 = 0.125G12 = 0.15G23 = 0.26G31 = 0.2εxx = ?εyy = ?εzz = ?εxy = ?εyz = ?εzx = ?

The calculation of stress is carried out as follows:

σxx = E1εxx + V21E2εyy + V31E3εzzσyy = V21E1εxx + E2εyy + V32E3εzzσzz = V31E1εxx + V32E2εyy + E3εzzσxy = G12εxy + G23εyz + G31εzxNow substituting the values:σxx = (2.5)(2.5)εxx + (0.2)(2)(2)εyy + (0.15)(2.5)(2.5)εzzσyy = (0.2)(2.5)(εxx) + (2)(2)εyy + (0.125)(2.5)εzzσzz = (0.15)(2.5)(εxx) + (0.26)(2)(εyy) + (2.5)εzzσxy = (0.15)εxy + (0.26)εyz + (0.2)εzx

Thus, the stresses acting on the surfaces of haulage excavated in an orthotropic rock mass given the following parameters acting at a point around the peripheral of the excavation are as follows:σxx = 6.25εxx + 0.8εyy + 1.875εzzσyy = 0.5εxx + 4εyy + 0.3125εzzσzz = 0.375εxx + 0.52εyy + 2.5εzzσxy = 0.15εxy + 0.26εyz + 0.2εzx

Thus the stresses acting on the surfaces of haulage excavated in an orthotropic rock mass is obtained.

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The voltage drop across the capacitor is 0V, across the resistor is  E = 125V,  the charge on the capacitor is 0C, the current through the resistor is 16.67 mA, and after the circuit is completed across the capacitor becomes E = 125V and current through the resistor becomes 0A.

(a) Just after the circuit is completed, the voltage drop across the capacitor is 0V. This is because an uncharged capacitor initially behaves like a short circuit, allowing the current to flow through without any resistance.

(b) The voltage drop across the resistor just after the circuit is completed is equal to the emf source, E = 125V. This is because the capacitor is acting like a short circuit, and the entire voltage is dropped across the resistor.

(c) Just after the circuit is completed, the charge on the capacitor is 0C (Coulombs). This is because it takes time for the capacitor to charge, and initially, it has no charge stored.

(d) The current through the resistor just after the circuit is completed can be calculated using Ohm's Law: I = V/R. In this case, V = 125V (voltage drop across the resistor) and R = 7.50 kΩ.

So, I = (125V)/(7.50 kΩ)

= 0.01667 A or 16.67 mA.

(e) A long time after the circuit is completed, the following occurs:

- The voltage drop across the capacitor becomes equal to the emf source, E = 125V. This is because the capacitor is now fully charged, and the voltage across it is equal to the voltage supplied by the source.

- The voltage drop across the resistor becomes 0V. This is because, when the capacitor is fully charged, it acts like an open circuit, and no current flows through the resistor.

- The charge on the capacitor can be calculated using the formula Q = C * V, where C is the capacitance (4.60 pF) and V is the voltage across the capacitor (125V).

So,\(Q = (4.60 \times 10^{-12} F) \times (125V)\)

= 5.75 * 10⁻¹⁰ C or 575 pC.

- The current through the resistor becomes 0A. This is because, when the capacitor is fully charged, it acts like an open circuit, and no current flows through the resistor.

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The unknown variables in the model equation for ball's motion include vertical distance traveled by the ball which is 31.86 m and the final velocity of the ball which is 25 m/s.

The given parameter;

The equations that model the motion of the ball is given as follows;

\(h = v_0_y + \frac{1}{2} gt^2\)

\(v_f = v_0_y + gt\)

All the unknown variables in the equations include;

The vertical distance traveled by the ball is calculated as follows;

\(h = \frac{1}{2} gt^2\\\\h = 0.5 \times 9.8 \times 2.55^2\\\\h = 31.86 \ m\)

The final velocity of the ball is calculated as follows;

\(v_f = 0 + 9.8(2.55)\\\\v_f = 25 \ m/s\)

Thus, the unknown variables in the model equation for ball's motion include vertical distance traveled by the ball which is 31.86 m and the final velocity of the ball which is 25 m/s.

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The correct answer is Upthrust= 0.7N and Volume = 1.02 x 10⁻² g

Solid weighs.09 N in air.

Solid weighs less than liquid because of an upward force operating on it (solid weighs in liquid =.02 N).

A solid body experiences an upthrust when it is partially or entirely submerged in a fluid, such as water. In this case, the fluid's weight (water) equals the fluid's weight that the water has displaced.

upthrust is = to.09 -.02 N = 0.7N.

Upthrust = displaced liquid's weight

so that weight of liquid equal to volume of solid = 0.7 N

Volume of solid times mass of liquid = 0.07/9.8 = 0.00714 =  7.14 x 10⁻³ kg

Volume = Mass / density

Volume = 7.14 x 10⁻³ / 700

= 1.02 x 10⁻⁵ kg= 1.02 x 10⁻² g

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Answer: F = 32 N

Explanation:  

F= m x a

m = 8 kg

a = 4 m/s²

F = 8 kg x 4 m/s² = 32  kg m /s² = 32 Newton

The statements that are true are

Angular momentum is the product of the rotational inertia and angular speed of a rotating object.

Let

From the law of conservation of angular momentum, we have that

initial angular momentum equals final angular momentum

So, I₁ + I₂ = I₃ + I₄

Ixω₀ + 0 = Ixω + Iyω

Ixω₀ = Ixω + Iyω

From the above, we see that

Since I₄ > I₂ = 0,

The angular momentum of disk Y immediately after the collision is greater than the angular momentum of disk Y immediately before the collision.

Also, since I₁ + I₂ = I₃ + I₄,

The angular momentum of the disk X-disk Y system immediately after the collision is equal to the angular momentum of the system immediately before the collision.

So, the statements that are true are

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So, the magnitude of velocity concerning:

Hi! Here I will help you to solve problems related to the velocity vector. In this problem, we know that a particle moves at a certain speed with an angle (\( \sf{\theta} \)) on the x-axis. Of course, with conditions like this, velocity can be described on the x or y-axis. The result of the x-axis velocity is horizontal movement. On the other hand, the y-axis velocity is vertical movement. See the equation below to know the magnitude of velocity concerning the x and y-axis.

\( \boxed{\sf{\bold{v_x = v_i \cdot \cos(\theta)}}} \)

\( \boxed{\sf{\bold{v_y = v_i \cdot \sin(\theta)}}} \)

With the following condition:

\( \sf{v_x = v_i \cdot \cos(\theta)} \)

\( \sf{v_x = 20 \cdot \cos(275^{\circ})} \)

\( \sf{\bold{v_x \approx 1.74 \: m/s}} \)

\( \sf{v_y = v_i \cdot \sin(\theta)} \)

\( \sf{v_y = 20 \cdot \sin(275^{\circ})} \)

\( \sf{\bold{v_y \approx -19.92 \: m/s}} \)

So, the magnitude of velocity concerning:

Answer:

2*F

Explanation:

If we put an object of a given size exactly at a distance 2*F from the lens, the virtual image (the image generated by the lens) will be generated at a distance 2*F from the lens and the size will be equal to the size of the real object (but the image will be inverted)

Now let's do the math.

The relation between the distance of the object to the lens O, and the distance between the image and the lens I is:

1/O + 1/I = 1/F

solving for O, we get:

1/O = 1/F - 1/I = (I - F)/(F*I)

O = F*I/(I - F)

Such that the relation between the height of the original object, H and the height of the virtual image H' is:

H/H' =  -I/O

Replacing by O we get:

H/H' = -I/(F*I/(I - F))

If the sizes are equal, then H/H' = - 1  (remember that the image is inverted, thus the sign)

-1 = -I/(F*I/(I - F))

F*I/(I - F) = I

F*I = (I - F)*I

F = (I - F)

F + F = I = 2*F

The distance between the image and the lens is 2*F

O =  F*I/(I - F) = F*2*F/(2*F - F) =  2*F

The object is at a distance 2*F from the lens.

The best time for a company to hire a project manager is when the project begins, therefore the correct answer is option A

There are mainly five stages of the technological design

The first stage in every problem-solving procedure is identifying the problem that has to be resolved.

The second stage is to envision; the third stage is the planning of the selected product from the imaging stage.

The fourth step entails assessing, testing, and revising the final product.

Thus, The optimum moment for a business to appoint a project manager is when the project starts, thus option A is the appropriate response.

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The acceleration of the tennis ball just before it starts to fall down is approximately -9.8 m/s², indicating that its velocity is decreasing as it reaches the top of its trajectory.

When the tennis ball reaches its highest point, just before it starts to fall down, its velocity momentarily becomes zero. At this instant, the ball experiences an acceleration due to the force of gravity. In the absence of any other forces, this acceleration is equal to the acceleration due to gravity, denoted by "g."

On Earth, the average value for acceleration due to gravity is approximately 9.8 m/s². However, it's important to note that this value can vary slightly depending on factors such as altitude and location.

Since the ball is at its highest point, its acceleration is directed downward, opposite to its initial velocity. The acceleration due to gravity acts as a constant force that causes objects to accelerate toward the Earth's center. Therefore, the acceleration of the tennis ball just before it starts to fall down is approximately -9.8 m/s².

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When a coconut is at the top of a tree, it has a certain amount of gravitational potential energy due to its position relative to the ground. As it falls, this potential energy is converted into kinetic energy, which is the energy of motion.

The coconut will not be able to reach the same speed at the bottom of the tree as it would in the absence of air resistance. Therefore, the total energy of the coconut at the bottom of the tree, which is the sum of its kinetic and potential energy, will be less than the potential energy it had at the top of the tree.

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Answer:

It will cool down and become a cold black dwarf.

Explanation:

The electron degeneracy pressure slowly overwhelms gravity, and the white dwarf evaporates. As gravity overwhelms the electron degeneracy pressure, it will explode as a nova.

Crater rays are:

(c) lines of impact ejecta that extend very far from the ejecta blanket.

When a celestial body such as a meteoroid or asteroid impacts the surface of a planet or moon, it creates a crater. The impact ejecta consists of debris and material that is thrown out from the impact site and forms a blanket around the crater. Crater rays are the lines of ejecta that extend outward from the crater, sometimes for long distances, creating distinctive streaks or rays on the surface.

These rays are formed when the ejected material is thrown out with sufficient force and momentum, causing it to travel far from the crater site. Crater rays can be seen on various bodies in the solar system, including the Moon and other rocky planets or moons with impact craters.

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i hope it will help you

Explanation:

density to the amount of wood in a unit , per volume of wood. the ratio of dry weight and green volume of the given wood is basic wood density.

If a musical note has a frequency of 212 Hz and a wavelength of 425 m, its velocity is 90.1 m/s.

The speed of sound is a relationship between frequency and wavelength, mathematically represented as follows:

speed = frequency x wavelength

In this case, the frequency is 212 Hz and the wavelength is 0.425 m. Plugging these values into the equation gives:

speed = frequency x wavelength

speed = 212 Hz x 0.425 m

speed = 90.1 m/s

Therefore, we can affirm that the the speed of the sound of the musical note is 90.1 m/s.

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The period of the pendulum on the surface of Mars, where g = 3.71m/s², would be the same as the period on Earth, 1.70s.  The pendulum on the surface of Mars has a period of roughly 3.31 seconds, according to our calculation of this expression.

A basic pendulum's period is determined by the equation T = 2(L/g), where T is the period, L is the pendulum's length, and g is the acceleration brought on by gravity.

L = (T/(2))2g can be solved for on Earth with a period of 1.70s by rearranging the equation.

Using the same equation and the Mars surface gravity, g = 3.71m/s2, we can now get the period on Mars' surface: T\(_{mars}\) = 2(L/g\(_{mars}\)).

The equation T\(_{mars}\) = 2(((T/(2))2g)/(g\(_{mars}\))) is obtained by substituting the expression for L and the surface gravity of Mars.

T\(_{mars}\) = T(g/g_Mars), to simplify the formula.

T\(_{mars}\) = 1.70s(9.81m/s2 / 3.71m/s) is the result of plugging in the data. The pendulum on the surface of Mars has a period of roughly 3.31 seconds, according to our calculation of this expression.

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Answer:

homo 1 3 hetero 2 4

Explanation:

The centripetal acceleration of the car driving at a constant speed of 21 m/s around a circle with a radius of 100 m is calculated to be 4.41\(m/s^2.\)

To find the centripetal acceleration of the car, we can use the formula:

a = \(v^2\) / r

where "a" represents the centripetal acceleration, "v" is the velocity of the car, and "r" is the radius of the circular path.

Given that the car drives at a constant speed of 21 m/s and the radius of the circle is 100 m, we can substitute these values into the formula to calculate the centripetal acceleration.

a = (21\(m/s)^2\)/ 100 m

a = 441 \(m^2/s^2\)/ 100 m

a = 4.41 \(m/s^2\)

Therefore, the centripetal acceleration of the car is 4.41\(m/s^2.\) This centripetal acceleration represents the inward acceleration that keeps the car moving in a circular path, and its magnitude is determined by the square of the velocity divided by the radius of the circle.

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Answer:

t = 7200.07seconds or 2 hours

Explanation:

given:

velocity (v) : 80km/h = 80 × 1000 m/ 60 × 60 s

= 80,000m/3600s => 22.222m/s

distance(d) = 160km => 160 × 1000 = 160,000m

time(t) = ?

since v=d/t

therefore, t= d/v

t= 160,000/22.222

t= 7,200.07seconds

or t= 7,200/3600 = 2 hours.

Answer:

The period is  \(T = 13.53 \ sec\)

Explanation:

From the question we are told that

     The length of the cable is  \(L = 45.5 \ m\)

Let take acceleration due to gravity as \(g = 9.8 \ m/s^2\)

Now the period of the oscillation is mathematically represented as

          \(T = 2 \pi \sqrt{\frac{L}{g} }\)

substituting values

          \(T = 2 * 3.142 \sqrt{\frac{45.5}{9.8} }\)

          \(T = 13.53 \ sec\)

Answer: 13.53

Explanation:

Answer: A

Explanation: ive done this already bro i just wanted to help

A location's net ocean current motion is 90 degrees to the right of the location's predominant wind direction.

This is brought on by the Coriolis force, which causes moving objects in the Northern Hemisphere to be deflected to the right and in the Southern Hemisphere to the left. The Earth's rotation produces the Coriolis force, which deflects the direction of moving things like ocean currents. In the Northern Hemisphere, the deflection is to the right, while in the Southern Hemisphere, it is to the left. Because the wind propels the surface currents, which are subsequently deflected by the Coriolis force, the direction of net ocean current motion at a site is 90 degrees to the right of the direction of the prevailing wind. Large-scale ocean circulation patterns, including the Antarctic Circumpolar Current in the Southern Ocean and the Gulf Stream in the North Atlantic, are created as a result.

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