Which idea did Ptolemy's model use to explain why the planets appeared to move backward as they moved in their orbits? The planets spun in epicycles. The planets rotated on their axes. The planets revolved around the Sun. The planets were made of different materials.

Answers

Answer 1

Answer:

The planets spun in epicycles.

Explanation:

The planets were not simply attached to a mystical sphere (“deferent”) but they were actually attached to a mini-sphere (“epicycle”) which rotated on the larger one.

Answer 2

Answer:A

Explanation:


Related Questions

How much energy is required to completely boil away 225 kg of water?
Hv = 226,000 J/kg
Hf = 334,000 J/kg

Answers

Answer:

E = 50850[kJ]

Explanation:

To boil the water we must use the latent heat of vaporization. Also we need to multiply this value by the mass of the water.

[tex]E=m*H_{v}[/tex]

Where:

E = energy produced by heat [J]

m = mass = 225 [kg]

Hv = 226000 [J/kg]

[tex]E = 225*226000\\E = 50850000 [J]\\E=50850[kJ][/tex]

I really need your help, please help me. How do I solve for ke without even having mass

Answers

I’m not fully sure - I’m studying the same topic as you in school and we haven’t covered it yet. BUT I can help you a teeny bit....

Note: You May know this but velocity means speed.

The formula for calculating kinetic energy is :

Ek = 1/2 mv2

E= kinetic energy ( J )
M= mass (kg)
V = velocity (m/s)

Help Please! a lot of points for 3 questions

Answers

Answer:

1. Point 2.

2. Either #1 or #4 (sorry, I'm not 100% sure).

3. I'm pretty sure #3.

I hope this helps!

HELP ME ASAP PLZZ

Which of the following is not a measurement taken by a radiosonde?

a. atmospheric composition

b. atmospheric pressure

c. wind speed

d. wind direction

Answers

Answer:

A atmospheric composition

Sultan travels 40 km north then 60 km west to reach the stadium and watch the football match. What
is Sultan's displacement?​

Answers

Answer:

72.11

Explanation:

Using the formula:

R^2=A^2+B^2

R= √ A^2+B^2

Where R= displacement

A=40km

B=60km

R= √ 40^2+60^2

R= √ 1600+3600

R= √ 5200

R=72.11km

substances found in the food that the body needs​

Answers

Answer:

There are six major nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water.

Explanation:

If an object of 10kg has gained 300J of GPE, what height has the object gained

Answers

The height has gained gravitational potential energy.

Starting from rest, a sprinter reaches his top velocity in 3 seconds. He runs a distance of 24m in 3 seconds. What is his acceleration? (Assume his acceleration is uniform)

Answers

Answer:

[tex]a=5.34\ m/s^2[/tex]

Explanation:

Given that,

Initial velocity of a sprinter, u = 0

He runs a distance of 24m in 3 seconds.

We need to find his acceleration. Let a be his acceleration. Using second equation of kinematics to find it.

[tex]s=ut+\dfrac{1}{2}at^2\\\\24=0+\dfrac{1}{2}a(3)^2\\\\a=\dfrac{24\times 2}{9}\\\\a=5.34\ m/s^2[/tex]

So, the acceleration of the sprinter is [tex]5.34\ m/s^2[/tex].

The acceleration of the sprinter from rest to his top speed is 5.33m/s²,

Given the data in the question

Since the sprinter starts from rest,

Initial velocity; [tex]u = 0[/tex]Time taken; [tex]t = 3s[/tex]Distance covered; [tex]s = 24m[/tex]

Acceleration; [tex]a = \ ?[/tex]

To determine the acceleration of the sprinter, we use the second equation of motion:

[tex]s = ut + \frac{1}{2}at^2[/tex]

Where s is distance covered, u is initial velocity, a is acceleration and t is time.

We substitute our given values into the equation

[tex]24m = [0 * 3s] + [\frac{1}{2} * a * (3s)^2]\\\\24m = \frac{1}{2} * a * 9s^2\\\\24m = a * 4.5s^2\\\\a = \frac{24m}{4.5s^2} \\\\a = 5.33m/s^2[/tex]

Therefore, the acceleration of the sprinter from rest to his top speed is 5.33m/s²

Learn more: https://brainly.com/question/18835025

How high did a worker lift a 25 kg bag of sand if it now has 2940 of gravitational potential energy

Answers

Answer:

12 m

Explanation:

From the question given above, the following data were obtained:

Mass (m) of bag = 25 kg

Potential energy (PE) = 2940 J

Height (h) =?

Objects carried to a particular height will always experience an acceleration due to gravity of 9.8 m/s².

With the above in mind, we can obtain the height to which the load is lifted to as shown below:

Mass (m) of bag = 25 kg

Potential energy (PE) = 2940 J

Acceleration due to gravity (g) = 9.8 m/s².

Height (h) =?

PE = mgh

2940 = 25 × 9.8 × h

2940 = 245 × h

Divide both side by 245

h = 2940 / 245

h = 12 m

Therefore, the worker lifts the load to a height of 12 m.

As the hot gas from a space shuttle is released downward, what does this cause to happen?
A. The shuttle will explode.
B. Negligible force on the shuttle.
C. Downward force on the shuttle.
D. Upward force on the shuttle

Answers

Answer:

D. Upward force on the shuttle

Explanation:

The hot gas from space shuttles released downward causes an upward force on the shuttle and propels it up the more.

This hot gas is produced from super cooled oxygen and hydrogen tanks within the shuttle. The upward force on the shuttle allows the craft to escape the gravitational pull of the earth on the shuttle Special level of rapid acceleration must be attained for the shuttle to escape the earth pull.

Advantages of wave model

Answers

Explanation:

plzz if it helps you then plzz mark me brainliest

A car traveled 1,215 km West from El Paso to Dallas in 13.5 hours. What was its velocity?

A. 90m/s West

B. 90km/h

C. .09km/h West

D. 90km/h West

Answers

Answer:

D. 90km/hr due West

Explanation:

Given parameters:

Displacement  = 1215km

Time  = 13.5hr

Unknown:

Velocity  = ?

Solution:

Velocity is the displacement divided by the time taken;

   Velocity  = [tex]\frac{displacement}{time}[/tex]   = [tex]\frac{1215km}{13.5hr}[/tex]   = 90km/hr

Velocity is 90km/hr due West

An 69-kg jogger is heading due east at a speed of 1.6 m/s. A 63-kg jogger is heading 14 ° north of east at a speed of 1.5 m/s. Find (a) the magnitude and (b) the direction of the sum of the momenta of the two joggers. Describe the direction as an angle with respect to due east.

Answers

Answer:

[tex]P=203.3819375kg.m/s\\P\approx203.4kg.m/s[/tex]

[tex]\theta=6.4541\textdegree North East\\\theta\approx6.5\textdegree North East[/tex]

Explanation:

From the question we are told that

Mass of first jogger [tex]M=69kg[/tex]

Speed[tex]v_1=1.6m/s[/tex]

Direction [tex]d= East[/tex]

Mass of 2nd jogger [tex]M=63kg[/tex]

Speed [tex]v_2=1.5m/s[/tex]

Direction [tex]d= 14\textdegree north[/tex]

Generally equation for momentum along the the horizontal is mathematically given as

[tex]P_x=m_1v_1 +m_2v_2cos\theta[/tex]

[tex]P_x=(69)*(1.6) +(63)*(1.5)cos14[/tex]

[tex]P_x=202.0929461kg.m/s[/tex]

Generally equation for momentum along the the vertical is mathematically given as

[tex]P_y=m_2v_2cos\theta[/tex]

[tex]P_x=22.86161913kgm/s[/tex]

a)Generally the magnitude of momentum is mathematically given by

[tex]P=\sqrt{(P_x)^2+(P_y)^2}[/tex]

[tex]P=\sqrt{(202.0929461)^2+(22.86161913)^2}[/tex]

[tex]P=\sqrt{41364.21249}[/tex]

[tex]P=203.3819375kg.m/s[/tex]

[tex]P\approx203.4kg.m/s[/tex]

b) Generally the angle [tex]\theta[/tex] is mathematically given by

[tex]\theta=tan^-^1\frac{py}{px} \\[/tex]

[tex]\theta=tan^-^1\frac{22.86161913}{202.0929461}[/tex]

[tex]\theta=tan^-^1(0.1131242805)[/tex]

[tex]\theta=6.4541\textdegree North East[/tex]

Hi!! Does anyone know this answer? :D

Answers

Answer:

Im not fully corrrect but I would say C

Explanation:

A simple pendulum has a period of 3.45 seconds. When the length of the pendulum is shortened by 1.0m,the period is 2.81 seconds, calculate (a) the original length of the pendulum (b) The value of acceleration due to gravity

Answers

Answer:

2.97 meters

9.85 m/s^2

Explanation:

Given that :

Period (T1) = 3.45 seconds

When length , l is shortened by 1m, period (T2) = 2.81 seconds

Using the relation :

T = 2π√l/g

g = acceleration due to gravity

T1 = 2π√L/g - - - - (1)

Period 2:

x = shortened length = 1m

T2 = 2π√L-x/g - - - (2)

Square both sides

T1² = (2π)² L/g - - - (3)

T2² = (2π)² L-x/g - - (4)

Divide 3 and 4

(T2/T1)² = (L-x) / L

(2.81/3.45)^2 = (L - 1) / L

0.6633984 = (L - 1) / L

0.6633984L = L - 1

0.6633984L - L = - 1

−0.336601L = - 1

L = 1 / 0.336601

L = 2.9708764

Length = 2.97 meters

Acceleration due to gravity :

g = L(2π/T1)^2

g = 2.97(2π / 3.45)^2

g = 2.97 * 3.3168172

g = 9.8509

g = 9.85 m/s^2

g

Which of these foods has the most protein?
Broccoli
Strawberries
Chicken
Brown Rice

Answers

Answer: Ima have to say broccoli

Explanation:

It’s chicken because chicken gives you protein

Think about holding a glass of cold water. Your hand is warmer than the glass. Do the particles in your hand or those in the glass of cold water move faster? Why?​

Answers

technically usually the warmer object/substances particles move master which causes friction among the particles plus the kinetic energy being converted to thermal energy, so i would say the hand.

What does the slope on a speed vs. time graph represent

Answers

Answer:

It represents the amount of speed per time or (x) for speed (y) for time so the slope would be like y/x

A hiker walks 5.0 kilometers due north for twenty minutes. He turns due west and travels 12 kilometers in 60 more minutes. Then he walks 7.0 kilometers due north in forty minutes. What is the average speed of the hiker when traveling north?

Answers

Answer:

The hikers average speed due north is 0.2 km per minute.

Explanation:

Speed is the ratio of distance moved by a body to the time taken.

i.e speed = [tex]\frac{distance}{time}[/tex]

Since the hiker walks due north and due west, then his average speed due north can be determined by;

Average speed = [tex]\frac{total distance due north}{total time taken}[/tex]

Total distance due north = 5.0 + 7.0

                                  = 12.0 km

Total time taken = 20 + 40

                           = 60 minutes

                           = 1 hour

Average speed due north= [tex]\frac{12}{60}[/tex]

                          = [tex]\frac{1}{5}[/tex]

                          = 0.2

Average speed due north = 0.2 km/minute

The hikers average speed due north is 0.2 km per minute.

The work done by a machine is always less then the work done on a
machine because of

Answers

Answer:

because of Friction is always present.

A 5.00 kg crate is on a 21.0° hill.
Using X-Y axes tilted down the
plane, what is the y-component
of the weight?
(Unit = N)

Answers

Answer:

17.56 N

Explanation:

Given that,

Mass of a crate, m = 5 kg

It is on a 21.0° hill

We need to find the y component of the weight.

y component = mgsinθ

Put all the values,

y-component = 5×9.8×sin(21)

= 49×sin(21)

= 17.56 N

So, the y-component of the weight is 17.56 N.

Answer:

-45.745

Explanation:

it is negative because it is downwards.

A guitar string is plucked. What best describes the formation and transmission of the sound wave?

The string vibrates the surrounding air, which produces a transverse wave.
The string vibrates the surrounding air, which produces a longitudinal wave.
The string produces a longitudinal wave that travels without a medium.
The string produces a transverse wave that travels without a medium.

Answers

The string vibrates the surrounding air, which produces a longitudinal wave.

Brainly if correct? Please and thank you :D

The guitar string vibrates the surrounding air, which produces a transverse wave.

What are transverse waves and longitudinal waves?Longitudinal waves:In a longitudinal wave, the medium or channel moves parallel to the wave in the same direction. Here, the particles are moving from left to right, which causes other particles to vibrate.Examples: sound waves in the air; vibration in a spring.

Transverse wavesThe medium or channel flows perpendicular to the wave's direction in a transverse wave. Here, the waves flow horizontally while the particles oscillate up and down.Examples: electromagnetic waves; waves in a string.

Why does plucking a guitar string produces transverse waves?

A transverse wave can be used to represent the motion of a guitar string since it oscillates up and down perpendicular to its axis of motion.

Learn more about waves produced due to plucking a string of guitar here:

https://brainly.com/question/15853432?referrer=searchResults

#SPJ2

Explain how the design of a racing car makes it less likely to turn over.​

Answers

The principles which allow aircraft to fly are also applicable in car racing. The only difference being the wing or airfoil shape is mounted upside down producing downforce instead of lift. The Bernoulli Effect means that: if a fluid (gas or liquid) flows around an object at different speeds, the slower moving fluid will exert more pressure than the faster moving fluid on the object. The object will then be forced toward the faster moving fluid. The wing of an airplane is shaped so that the air moving over the top of the wing moves faster than the air beneath it. Since the air pressure under the wing is greater than that above the wing, lift is produced. The shape of the Indy car exhibits the same principle. The shape of the chasis is similar to an upside down airfoil. The air moving under the car moves faster than that above it, creating downforce or negative lift on the car. Airfoils or wings are also used in the front and rear of the car in an effort to generate more downforce. Downforce is necessary in maintaining high speeds through the corners and forces the car to the track. Light planes can take off at slower speeds than a ground effects race car can generate on the track. An Indy ground effect race car can reach speeds in excess of 230 mph using downforce. In addition the shape of the underbody (an inverted wing) creates an area of low pressure between the bottom of the car and the racing surface. This sucks the car to road which results in higher cornering speeds.

The total aerodynamic package of the race car is emphasized now more than ever before. Teams that plan on staying competitive use track testing and wind tunnels to develop the most efficient aerodynamic design. The focus of their efforts is on the aerodynamic forces of negative lift or downforce and drag. The relationship between drag and downforce is especially important. Aerodynamic improvements in wings are directed at generating downforce on the race car with a minimum of drag. Downforce is necessary for maintaining speed through the corners. Unwanted drag which accompanies downforce will slow the car. The efficient design of a chassis is based on a downforce/drag compromise. In addition the specific race circuit will place a different demand on the aerodynamic setup of the car.

A road course with low speed corners, requires a car setup with a high downforce package. A high downforce package is necessary to maintain speeds in the corners and to reduce wear on the brakes. This setup includes large front and rear wings. The front wings have additional flaps which are adjustable. The rear wing is made up of three sections that maximize downforce.

The speedway setup looks much different. The front and rear wings are almost flat and are used as stabilizers. The major downforce is found in the shape of the body and underbody. Drag reduction is more critical on the speedway than on other circuits. Since the drag force is proportional to the square of the speed, minimizing drag is a primary concern in the speedway setup. Lap speeds can average over 228 mph and top speeds can exceed 240 mph on a speedway circuit. Effective use of downforce is especially pronounced in highspeed corners. A race car traveling at 200 mph. can generate downforce that is approximately twice its own weight.

Generating the necessary downforce is concentrated in three specific areas of the car. The ongoing challenge for team engineers is to fine tune the airflow around these areas.

When you listen to the radio, watch TV, or cook food in a microwave, you are making use of properties of electromagnetic waves. Which statement about electromagnetic waves is false?

A. White light is the absence of all color.
B. Higher-frequency electromagnetic waves have more energy.
C. The sun radiates several different types of electromagnetic energy.
D. The frequency of an electromagnetic wave is related to its wavelength.

Answers

Answer:

A. White light is the absence of all color.

Explanation:

It is false that white light is the absence of all color. In fact, white light is the presence of all colors in the spectrum.

Electromagnetic waves are waves that do not require any material medium for propagation. It is the interaction of electric and magnetic fields.

The higher frequency electromagnetic waves like the gamma-rays and x-rays have more energy. The sun furnishes the universe with electromagnetic energy. The higher the wavelength, the lesser the energy of the electromagnetic radiation.


The speed of a sound wave traveling through air is 400 meters per second. The wavelength of the wave is 25 meters What is the
frequency of the wave?

Answers

Answer:

16Hz

Explanation:

Given parameters:

Speed of sound  = 400m/s

Wavelength  = 25m

Unknown:

Frequency of the wave  = ?

Solution:

To solve this problem;

      V  = F ∧  

V is the velocity

F is the frequency

∧ is the wavelength

      400  = F x 25

        F  = 16Hz

Answer:

16 hertz... I got it right on study-island

Explanation:

Jeff throws a ball straight up. For which situation is the vertical velocity zero?
a. on the way up
b. at the top
c. on the way back down
d. none of the above

Answers

Answer:

b. at the top

Explanation:

At the top of the climb, the vertical velocity of Jeff's throw has a value of zero.

Vertical velocity in this instance is acting against the acceleration due to gravity.

At the top of the thrown, the force of the throw becomes zero and the velocity also becomes zero. As the body finds it way downward, it begins to fall freely. The fall is due to the acceleration due to gravity which is experienced by every object on earth.

What is the speed of a wave with a wavelength of 2 m and a frequency of 9 Hz?

Answers

Answer:

The speed of a wave would be 18 with a wavelength of 2 m and a frequency of 9 Hz.

WILL MARK BRAINLIST!!! only for correct answer
NEED CORRECT ANSWER ASAPPP

Answers

Answer:

number 4

Explanation:

The reflection of light happens when the light bounces off the reflecting surface. That is described by the last (bottom) schematics.

Therefore, select answer number 4.

Please help for 30 points

write at least 3 rules that summarize how magnets move objects.

Answers

Answer:

Magnets work by using Earth's magnetic pull.

Explanation:

Magnets move objects because they are made of steel or metal. And for that reason, they can stick to objects that are metal.

1-long, straight wires, 2-free moving charges in magnetic fields, and 3-the solenoid rule (which are loops of current)

Which one of the following is correct? *

A. Average speed and average velocity are the same.

B. There is no difference between uniform motion and uniformly accelerated motion.

C. Acceleration is the rate of change of speed.

D. Uniformly accelerated motion is a motion with constant acceleration.​

Answers

Answer:

uniform acceleration motion is a motion with constant acceleration.

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