how could we develop space travel?

Ptolemy was important in the history of astronomy because he developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries. Correct answer: letter C.

Ptolemy was an ancient Greek scientist who developed a model of the solar system that placed the Sun at the center, rather than the Earth. This model was able to make sufficiently accurate predictions of planetary positions to remain in use for many centuries, and was thus an important part of the history of astronomy.

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Given data

*The weight of the box is W = 500 N

*The distance of the plank from the fulcrum is d = 5 m

*The given force at a distance from the fulcrum is D = 10 m

The minimum force is required to lift the box is given by the net torque as

Substitute the known values in the above expression as

Hence, the minimum force is required to lift the box is F = 250 N

Explanation:

because the boy has larger surface area due to which he offers the larger air resistance which decreases the acceleration so, he will fall towards the earth's surface approximately with constant velocity.

The period of a simple pendulum is directly proportional to the square root of the length of the pendulum and inversely proportional to the square root of the acceleration due to gravity.

Therefore, the period of the simple pendulum on Mars can be calculated using the following formula:
T_mars = T_earth * sqrt(L_earth/L_mars) * sqrt(g_mars/g_earth)
Where T_the earth is the period of  pendulum on Earth (given as 1.72 s), L_earth is the length of the pendulum on Earth (which is not given), L_mars is the length of the pendulum on Mars (which is assumed to be the same as on Earth), g_mars is the acceleration due to gravity on Mars (given as 3.71 m/s^2), and g_earth is the acceleration due to gravity on Earth (which is assumed to be the same as on Earth).

Simplifying the equation by cancelling out L_earth and assuming L_mars = L_earth, we get:
T_mars = T_earth * sqrt(g_earth/g_mars)
Substituting the given values, we get:
T_mars = 1.72 * sqrt(9.81/3.71) = 2.67 s

Therefore, the period of the simple pendulum on the surface of Mars is 2.67 s.

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Answer:

Moving electrons by cringing the object near another charged object ... This means that there is a different number of protons and electrons ... the attraction or repulsive electrostatic force between positive and negative charges ... the amount of charge on the particle and the distance between the particles ... fixed in position.ation:

According to the data given in the question the net force on the box is of 5 N.

All of the forces that are applied to an object are added up to form the net force. As a consequence of the fact that it (force) is a vector and therefore that two forces with identical magnitudes and opposing directions cancel each other out, the resultant force is the total of the forces, or put another way, the net force is just the total of all the forces.

Given data :

Force on box to the left side (F1) = 15 N

Force on box to the right side (F2) = 20 N

Because both forces are in opposite direction

Hence,

Net force = F2 - F1

Net force = 20 - 15

Net force = 5 N.

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In 3.3 hours, the distance traveled by the first airplane heading at 37.5° at 650 mph is :a = 650*3.3 = 2145 miles.

The second airplane travels

b = 650*3.3 = 2145 mile

The angle between the two airplanes is

181° - 37.5° = 143.5°

Let c =  the distance between the two airplanes after 3.3 hours.

From, Law of Cosines, obtain

c² = a² + b² - 2ab cos(143.5°)

   = 4.6 x 10⁶ + 4.6 x 10⁶

c = 5718.15mile far apart are they

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Answer:

The torque necessary to bring the wheel to rest in 40 seconds is 10.4 N·m

Explanation:

The question is with regards to rotational motion

The rotary motion parameters are;

The mass of the wheel = 50 kg

The radius of the wheel = 0.4 m

The rate of rotation of the wheel = 480 rpm

The time in which the wheel is to be brought to rest = 40 s

The rotational rate of the wheel in rotation per second is given as follows;

480 r.p.m = 480 r.p.m × 1 minute/(60 seconds) = 8 revolution/second

1 revolution = 2·π radians

Therefore, we have the angular velocity, ω, given as follows;

ω = 2·π × 8 revolutions/second ≈ 50.3 rad/s

The angular acceleration, α, is given as follows;

\(\alpha = \dfrac{\Delta \omega}{\Delta t} = \dfrac{\omega _2 - \omega_1}{t_2 - t_1}\)

Whereby the wheel is brought to rest from its initially constant rotational motion in 40 seconds, we have;

ω₁ ≈ 50.3 rad/s, ω₂ = 0 rad/s, and t₂ - t₁ = 40 seconds

Plugging in the values for the variables of the equation for the angular acceleration, "α", we get;

\(\alpha = \dfrac{0 - 50.3 \ rad/s}{40 \ s} \approx 1.3 \ rad/s^2\)

The torque on the wheel, τ, is given as follows;

τ = m·r²·α

Where;

m = The mass of the object = 50 kg

r = The radius of the wheel = 0.4 m

α = The acceleration of the wheel ≈ 1.3 rad/s²

Therefore;

τ = 50 kg × (0.4 m)² × 1.3 rad/s² ≈ 10.4 N·m

The torque necessary to bring the wheel to rest in 40 seconds = τ ≈ 10.4 N·m.

Answer:

-10.048 N m

Explanation:

Answer:

25 joules

Explanation:

Not sure I understood correctly but since 15 are taken up by mechanical energy and 10 are taken in by electrical, 50-10-15 would result in 25 joules which must belong to heat energy

Answer:

B; Linear

Explanation:

The last one is the correct answer,Also can I get brainliest

Answer:

&3?.&.)/&282/8//8338/.)9

Explanation:&3?.&.)/&282/8//8338/.)9

The changes of energy in an electrical train as it approaches a station and breaks to halt are potential energy → friction → heat and sound

- → friction on train wheels due to brakes reduces KE of train to zero

- → heat and sound to surroundings

Energy, according to scientists, is the capacity for work. The ability to transform energy from one form to another and use it to perform tasks is what makes modern civilization possible. People utilize energy to travel by foot and bicycle, drive vehicles on land and in water, prepare meals on stoves, create ice in freezers, illuminate our homes and workplaces, create goods, and launch people into space.

Energy comes in a wide variety of forms, including:

These energies can be divided into two categories for working energy:

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To calculate the stress in MPa (megapascals) on a circular rod, we need to know the force applied and the diameter of the rod. In this case, a force of 10 newtons is applied to one end of a circular rod with a diameter of 10 inches.

First, we need to convert the diameter from inches to meters since the SI unit for length is meters. One inch is approximately equal to 0.0254 meters. So, the diameter of the rod is 10 inches * 0.0254 meters/inch = 0.254 meters.

Next, we can calculate the stress using the formula:

Stress = Force / Area

The area of a circular rod is given by the formula:

Area = π * (diameter/2)^2

Substituting the values into the formulas, we get:

Area = π * (0.254 meters/2)^2 = π * (0.127 meters)^2

Stress = 10 newtons / (π * (0.127 meters)^2)

Finally, we can calculate the stress in MPa by converting the stress from pascals to megapascals. 1 MPa is equal to 1,000,000 pascals.

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The blanks that are filled in order to complete this passage about geologic processes are as follows:

Erosion may be characterized as the geological methodology through which earthen materials and compounds like soil or small rock particles are significantly scoured and migrated by natural forces such as wind or water.

Weathering may also be defined as the strategy of geology which scientifically deals with the detailed study of breaking down or dissolving rocks and minerals on Earth's surface with the help of natural as well as human interference.

Therefore, the blanks that are filled in order to complete this passage about geologic processes are appropriately filled.

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Answer:

The train stopped for 3 seconds.

Explanation:

D on edge

The kinetic energy of a falling tree limb can be calculated by considering the change in potential energy as it falls to the roof.

The potential energy of an object at a certain height is given by the formula \(PE = mgh\), where m is the mass of the object, g is the acceleration due to gravity, and h is the height.

In this case, the tree limb has a mass of 60.0 kg and is initially at a height of 20.0 m. The potential energy of the limb at this height is:

PE = (60.0 kg) * (9.8 m/s^2) * (20.0 m) = 11,760 J

As the limb falls and reaches the roof, all of its potential energy is converted into kinetic energy. Therefore, the kinetic energy of the limb when it reaches the roof is equal to its initial potential energy:

KE = 11,760 J

Hence, the kinetic energy of the limb when it reaches the roof is 11,760 Joules.

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Answer:

112.23 m

Explanation:

Displacement is the final position minus the initial position.

Δx = x − x₀

Δx = 100.1 m − (-12.13 m)

Δx = 112.23 m

The ratio u₁/u₂ is equal to (m₁/m₂)×(r₁/r₂). The potential energy of a planet-satellite system is given by the formula U = -G(m₁m₂)/r, where G is the gravitational constant, m₁ and m₂ are the masses of the planet and satellite, and r is the distance between their centers.

In circular orbits, the kinetic  of the satellite is equal to half of its potential energy, so the total energy of the system is negative and equal in magnitude to the potential energy.

Using this formula, we can write u₁ = -G(mm₁)/r₁ and u₂ = -G(m×m₂)/r₂.

Dividing u₁ by u₂, we get:

u₁/u₂ = (-G(m m₁)/r₁) / (-G(m m₂)/r₂)
u₁/u₂ = (m₁ r₂) / (m₂ r₁)
u₁/u₂ = (m₁/m₂) (r₂/r₁)

Since the satellites are in circular orbits, their speeds are given by the formula v = √(Gm/r),

where v is the speed, G is the gravitational constant, m is the mass of the planet, and r is the radius of the orbit.

Therefore, we can write r₂/r₁ = (v₁/v₂)².

Substituting this into the previous equation, we get:

u₁/u₂ = (m₁/m₂) ((v₁/v₂)²)

The ratio u₁/u₂ is equal to (m₁/m₂) (v₁/v₂)², where m₁ and m₂ are the masses of the two satellites, v₁ and v₂ are their speeds, and r₁ and r₂ are their orbital radii.

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Answer:

4200 Newtons

Explanation:

Force = mass x acceleration

1200 x 3.5 = 4200

Answer:

Asexual production they can be eukaryotes or prokaryotes

Explanation:

Answer:

Density= 2.78 g/cm³

Relative density=2.8

Explanation:

To calculate the density of the cube we have to use the formula ρ=mass/volume

ρ stands for density.

So now we don't have the volume of the cube and to find the volume of the cube we have to use the formula a³

3³= 9 cm³

Now plug in the values. ρ= 25 g/9 cm³

ρ= 2.78 g/cm³

To find the relative density, we have to use the formula ρsample/ρH20

The sample means the density of the substance earlier. We do not know the density of water but it is constant at 997 kg/m³.

Now we have to make the units same so you change the unit of the density of cube to kg/m³

So, 25/1000= 0.025 kg

9/100×100×100 (because cm³ which means that there should be 3 meters to change the unit and to conver cm to meter we need to divide by 100 so 9cm/100, 9cm²/100×100, 9cm³/100×100×100)

=0.000009 m³

The new density= 0.025 kg/ 0.000009 m³

= 2777.78 kg/m³

Now plug the values into the formula:

relative density= 2.777.78 kg/m³ / 997 kg/m³

=2.8

There is no unit since kg/m³ and kg/m³ cancels

6.21 cm

where

Given:

solving step-wise:

\(\dashrightarrow \mathrm{T}=2 \pi \sqrt{\dfrac{\mathrm{L}}{\mathrm{g}}}\)

\(\sf \dashrightarrow \mathrm{0.5}=2 \pi \sqrt{\dfrac{\mathrm{L}}{\mathrm{9.8}}}\)

\(\dashrightarrow \mathrm{\dfrac{0.5}{2 \pi } }=\sqrt{\dfrac{\mathrm{L}}{\mathrm{9.8}}}\)

\(\dashrightarrow\sqrt{\dfrac{\mathrm{L}}{\mathrm{9.8}}}= \mathrm{\dfrac{0.5}{2 \pi } }\)

\(\sf \dashrightarrow{\dfrac{\mathrm{L}}{\mathrm{9.8}}}= (\mathrm{\dfrac{0.5}{2 \pi } })^2\)

\(\sf \dashrightarrow{{\mathrm{L}}= (\mathrm{\dfrac{0.5}{2 \pi } })^2*9.8\)

\(\sf \dashrightarrow{{\mathrm{L}}=0.06205922 \ m\)

\(\sf \dashrightarrow{{\mathrm{L}}=6.2059\ cm\)

\(\sf \dashrightarrow{{\mathrm{L}}=6.21\ cm\)             { rounded to nearest hundredth }

Let's see

\(\\ \rm\rightarrowtail T=2\pi \sqrt{\dfrac{l}{g}}\)

\(\\ \rm\rightarrowtail 0.5=2\pi \sqrt{\dfrac{l}{9.8}}\)

\(\\ \rm\rightarrowtail 0.783=\pi \sqrt{l}\)

\(\\ \rm\rightarrowtail 0.2494=\sqrt{l}\)

\(\\ \rm\rightarrowtail \ell=0.0622m\)

Answer:

That is very true, there can never be 100% energy conversion.

Hence, the ladder top to touch ground the ladder base should pull back a distance of ( 6 - 3 ) = 3 meters on ground As the rate of sliding of base of ladder is 0.5 meter per second , it takes a time of [  3/ (0.5) ] = 6 seconds.

What is Distance? Distance is the total movement of an object without any regard to direction. We can define distance as to how much ground an object has covered despite its starting or ending point.

Distance measures length. For example, the distance of a road is how long the road is. In the metric system of measurement, the most common units of distance are millimeters, centimeters, meters, and kilometers.

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Answer:

a) The distance covered by the moving object is approximately 18.85 km

b) The magnitude of the displacement of the object is 0 (no displacement)

Explanation:

From the drawing, we have;

The sale of the drawing is 1 unit = 1 km

The radius of the circle in the drawing along which the object moves = 3 units

Therefore;

The radius of the circle along which the object moves, r = 1 km/unit × 3 units = 3 km

a) The distance covered by the object that moves from point A to B to C to D and finally to A is equal to the circumference of the circle

Therefore;

The distance covered by the moving object, d = 2·π·r

By pugging the value for r = 3 km

d = 2 × π × 3 km = 6·π km ≈ 18.85 km

The distance covered by the moving object, d ≈ 18.85 km

b) The displacement = The object's change in position

The initial position of the object = Point A

The final position of the object = Point A

Therefore, the displacement of the object, A = No displacement = 0 (No difference between the initial and final location of the object

The net force on particle q2 can be calculated by finding the net electric force acting on it. The net electric force acting on a particle is the vector sum of the forces exerted by all the other charges on it.

The electric force between two charges q1 and q2 is given by Coulomb's law: F = k * (q1 * q2)/r^2, where k is Coulomb's constant, q1 and q2 are the charges, and r is the distance between them.

The force on particle q2 due to q1 will be:

F1 = k * (q1 * q2) / (0.980m)^2

The force on particle q2 due to q3 will be:

F2 = k * (q2 * q3) / (0.750m)^2

The net force acting on q2 will be the vector sum of F1 and F2.

Keep in mind, q1 and q3 have opposite charges, so they attract each other, while q2 has the same charge as q1, so they repel each other.

Note: The unit of charge is Coulomb (C), but in this problem you are given the charges in microCoulomb (uC) so you need to convert it to Coulomb.

C. A heat pump absorbs 100 J of heat from a cool reservoir and releases 120 J of heat to a hot reservoir.

In order to operate, a heat engine must reject some of the heat it receives from the high-temperature source to a low-temperature sink.

A heat engine that violates the second law converts 100 percent of this heat to work. This is physically impossible. This heat engine violates the second law of thermodynamics.

The second law can also be stated as no heat engine can have a thermal efficiency of 100 percent.

The thermal efficiency of a heat engine is defined as the ratio of the work output to the heat input:

Clearly, if the thermal efficiency of a heat engine is 100 percent,

Qin=Wout

If the second law precludes a heat engine from having a thermal efficiency of 100 percent. A heat engine is a device that converts a portion of the heat supplied to it from a high-temperature source into work. The remaining heat is rejected to a low-temperature sink.

Therefore:

A heat pump absorbs 100 J of heat from a cool reservoir and releases 120 J of heat to a hot reservoir.

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The dot product is 25, the angle is \(\theta = cos^{-1} \frac{25}{\sqrt{35} \times \sqrt{21}}\), the cross product is 1i + (-6)j + (-7)k, and the area of the parallelogram spanned by vectors A and B is \(\sqrt{86}\).

Given,

A = 5i + 3j + k

B = 4i + j + 2k

i. Dot Product (A · B):

The dot product of two vectors A and B is given by the sum of the products of their corresponding components.

\(A.B = (A_x \times B_x) + (A_y \times B_y) + (A_z \times B_z)\\A.B = (5 \times 4) + (3 \times 1) + (1 \times 2) \\= 20 + 3 + 2 \\= 25\)

ii. Angle between vectors A and B:

The angle between two vectors A and B can be calculated using the dot product and the magnitudes of the vectors.

\(cos\theta = (A.B) / (|A| \times |B|)\\\theta = \frac{1}{cos} ((A.B) / (|A| \times |B|))\\A = \sqrt{(5^2 + 3^2 + 1^2)} =\\ \sqrt{35}\\B = \sqrt{(4^2 + 1^2 + 2^2)} \\= \sqrt{21}cos\theta = \frac{(A.B) / (|A| \times |B|)\\\theta = \frac{1}{cos} \frac{25}{\sqrt{35} \times \sqrt{21}}}\)

iv. Cross Product (A × B):

The cross product of two vectors A and B is a vector that is perpendicular to both A and B and its magnitude is equal to the area of the parallelogram spanned by A and B.

\(A\times B = (A_y \timesB_z - A_z \timesB_y)i + (A_z \timesB_x - A_x \timesB_z)j + (A_x \times B_y - A_y \times B_x)k\\A\times B = ((3 \times 2) - (1 \times 1))i + ((1 \times 4) - (5 \times 2))j + ((5 \times 1) - (3 \times 4))k\\= 1i + (-6)j + (-7)k\)

Area of the parallelogram spanned by vectors A and B:

The magnitude of the cross product A × B gives us the area of the parallelogram spanned by A and B.

Area = |A × B|

Area of the parallelogram spanned by vectors A and B:

Area = |A × B| =

\(\sqrt{(1^2 + (-6)^2 + (-7)^2}\\\sqrt{1+36+49\\\\\sqrt{86}\)

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