9. When a balloon rises into the air, it
A. Expands on cooling
B. Contracts on cooling
C Expands on heating
D. Contracts on heating

Answers

Answer 1

Answer:

Answer 3: When a balloon goes up higher in the air, its size will increase. Since there's less air in the upper atmosphere, there's less stuff pushing back on the balloon, and hence the pressure is lower, which allows the balloon to expand

Answer: C

Explanation:

As the balloon rises, the gas inside the balloon expands because the atmospheric pressure surrounding the balloon drops. The atmosphere is 100 to 200 times less dense at the float altitudes than on the ground. and as the air is heated inside the balloon it causes it to rise upwards (because it is lighter than the cooler air on the outside). When the pilot needs to bring the balloon down again, he simply reduces the temperature of the air inside the balloon causing it to slowly descend.


Related Questions

Give reason.


b} String roller is an example of wheel and axel .Why?

Answers

Explanation:

string roller is called an example of wheel and axel because The thin rod which needs to be turned is called the axle and the wider object fixed to the axle, on which we apply force is called the wheel.

hence the we apply force on the roller and the string gets tight.

Guys please help this is very important it would be greatly appreciated if you would add the work. Thank you !!

Answers

Answer:

enjoy

Explanation:

The number of time a cricket chirps in a minute is a function of the temperature in the formula: n=4t-160, where n=number of times a cricket chirps a minute and t=temperature in farenheit. You can use the temperature t=(1/4)n+40 to estimate the temperature based on the number of chirps per minute.

the diameter of circular park is 80 m find its area​

Answers

Explanation:to find the area you must first find the radius given you have the diameter you cut the diameter in half giving you 40 then you follow the formula “A= (pie)r (squared) leaving you with

answer:5024

Observe the given figure and find the the gravitational force between m1 and m2.​

Answers

Answer:

The gravitational force between m₁ and m₂, is approximately 1.06789 × 10⁻⁶ N

Explanation:

The details of the given masses having gravitational attractive force between them are;

m₁ = 20 kg, r₁ = 10 cm = 0.1 m, m₂ = 50 kg, and r₂ = 15 cm = 0.15 m

The gravitational force between m₁ and m₂ is given by Newton's Law of gravitation as follows;

[tex]F =G \cdot \dfrac{m_{1} \cdot m_{2}}{r^{2}}[/tex]

Where;

F = The gravitational force between m₁ and m₂

G = The universal gravitational constant = 6.67430 × 10⁻¹¹ N·m²/kg²

r₂ = 0.1 m + 0.15 m = 0.25 m

Therefore, we have;

[tex]F = 6.67430 \times 10^{-11} \ N \cdot m^2/kg \times \dfrac{20 \ kg\times 50 \ kg}{(0.1 \ m+ 0.15 \ m)^{2}} \approx 1.06789 \times 10^{-6} \ N[/tex]

The gravitational force between m₁ and m₂, F ≈ 1.06789 × 10⁻⁶ N

Which are characteristics of a prokaryotic cell? Select three options.


O contains DNA

O lacks DNA

O contains ribosomes

O lacks ribosomes

O contains a nucleus

O lacks a nucleus

I NEED THIS QUICKLY

Answers

Answer:

A. Contains DNA

C. Contains ribosomes

F. Lacks a nucleus

Explanation:

A car travels first 10 km in 20 minutes and another 10 km in 30 minutes. What is the average speed of the car in m/s?

Answers

Total distance = 10 km + 10 km = 20 km

1 km = 1000 m

20km x 1000 = 20,000 m

Total time = 20 min. + 30 min. = 50 minutes

Average speed = Distance /  time

Average speed = 20,000/50 min

Average speed = 400 m/s

3 write the three laws given by kepler.How did they help Newton to arrive at the inverse square law of gravity?​

Answers

Answer:

Kepler's laws apply: First Law: Planetary orbits are elliptical with the sun at a focus. Second Law: The radius vector from the sun to a planet sweeps equal areas in equal times. Third Law: The ratio of the square of the period of revolution and the cube of the ellipse semimajor axis is the same for all planets.

any correct ans guess for 30 pts and brainlist​

Answers

Answer:

a) ii

b) i

c)iii

d)iii

e) i

f)iii

Explanation:

i hope this will help

Answer:

the answer of b is N and d is mol

A 5.41 kg ball is attached to the top of a vertical pole with a 2.37 m length of massless string. The ball is struck, causing it to revolve around the pole at a speed of 4.75 m/s in a horizontal circle with the string remaining taut. Calculate the angle θ, between 0∘ and 90∘, that the string makes with the pole. Use g=9.81 m/s2.

Answers

Answer:

θ = 66º

Explanation:

This exercise of Newton's second law must be solved in part, let's start by finding the slowing down acceleration of the ball

           a = v² / r

the radius of the circle is

          sin θ = r / L

          r = L sin θ

           

we substitute

          a = v² /L sin θ

now let's write Newton's second law

vertical axis

            T_y -W = 0

             T_y = W

radial axis

            Tₓ = m a                 (1)

let's use trigonometry for the components of the string tension

             cos θ = T_y / T

             sin θ = Tₓ / T

             Tₓ = T sin θ

we substitute in 1

            T sin θ = [tex]\frac{m \ v^2}{L \ sin \theta}[/tex]

             T L sin² θ = m v²

we write our system of equations

             T cos θ  = m g

             T L sin ² tea = m v²

we divide the two equations

             L [tex]\frac{sin^2 \theta}{cos \theta}[/tex] = v² / g

             (1 -cos²)/ cos θ  = [tex]\frac{v^2 }{g \ L}[/tex]

             1 - cos² θ  =  [tex]\frac{4.75^2}{9.81 \ 2.37}[/tex]   cos θ

             cos² θ + 0.97044 cos θ -1   = 0

we change variable    cos  θ = x

             x² + 0.97044 x - 1 =0

             x= [tex]\frac{-0.97 \pm \sqrt{0.97^2 - 4 1} }{2}[/tex]

           since the square root is imaginary there is no real solution to the problem, suppose that the radius is 1 m r = 1 m

           T sin θ = [tex]\frac{m \ v^2}{ r}[/tex]

           T cos θ  = m g

resolved

           tan θ =  [tex]\frac{v^2}{ r g}[/tex]

           θ = tan⁻¹ ( 4.75²/ 1 9.81)

           θ = 66º

A long distance runner running a 5.0km track is pacing himself by running 4.5km at 9.0km/h and the rest at 12.5km/h. What is his average speed?

Answers

Answer:

9.26 km/h

Explanation:

Applying,

V' = D'/t'............... Equation 1

Where V' = Average speed, D' = Total distance, t' = total time.

Given: D' = 5 km

But,

v = d/t............ Equation 2

Where v = speed , d = distance, t = time

t = d/v............ Equation 3

Given: d = 4.5 km, v = 9 km/h, and d = 0.5 km, v = 12.5 km/h

Therefore,

t₁ = 4.5/9 = 0.5 hours

t₂ = 0.5/12.5

t₂ = 0.04 hours

Therefore,

V' = 5/(0.5+0.04)

V' = 5/0.54

V' = 9.26 km/h

Wat is acceleration!!!!!​

Answers

Answer:

Acceleration is the rate of change of velocity with time.its system international unit is meters per second square.

I hope this helps

Which type of electromagnetic wave is deliberately used in some
circumstances to cause damage to living cells in the human body?
A. Infra-red
B. Gamma rays
C. Microwaves
D. Radio waves.

Answers

Gamma rays

used in radiotherapy

Answer the following questions 1 What is the difference between mass and weight of an object. Will the mass and weight of an object on the earth be same as their values on Mars ? Why? ​

Answers

Answer:

difference between mass and weight is that mass is amount of matter in a material while weight is a measure of how the force of gravity acts upon that mass.the mass of an object will be same on earth and mars but its weight on both planets will be different.

A converging lens of focal length 20cm, forms a real image twice the size of the object. Calculate:
i) the power of the lens;
ii) the position of the image.

Answers

Answer:

Solition given:

focal length(f)=20cm

size of image(v)=2x

size of object(u)=x

we have

power of lens= reciprocal to focal length=1/20=0.05/cm

ii.

the position of the image is beyond C.

Explanation:

See the attachment !!!!!!!

1.Convert 340 cm into m *(answer=0.34m)

2.What is the weight of potatoes of mass 75kg on the surface of the earth? *(ans=735 N)

[g=9.8 m/s^2

[g=9.8 m/s^2]

3.The weight of body is 420 N.Calculate its mass. *(42.857 kg)*


Answers are all given so i just need the process please (i will mark you brainliest please..

Answers

Answer:

1.for the first one 100centimeters make 1 meter therefore

100cm-1m

340cm-x

340/100

=3.4

the answer is supposed to be 3.4, maybe there's a mistake with the question or the answer

2.the weight of a body is given by the formula

mass×gravity,in this case the mass is 75kg and the gravity is 9.8

weight=75×9.8

=735N

3.for this one the mass of a body is given by the formula

mass=weight/gravity

=420/9.8

=42.8kg

I hope this helps

what is velocity give its SI unit​

Answers

Answer:

Velocity is the speed of something given in a direction. the SI unit of velocity is metre per second or m/s.


1. What type of VOM reading requires the meter to be placed in series with the circuit?
A. Resistance
B. Voltage
C. Current
O
D. Power

Answers

Answer:

C.  Current.

Explanation:

In a series circuit the current is equal in all of its components, so to measure the current we put the meter in series with the circuit.

A compound eye __________. ANSWER Unselected is composed of thousands of prisms that focus light onto only a few photoreceptor cells Unselected All of the listed responses are correct. Unselected works best for resolving stationary images Unselected contains many individual light detectors, each with its own lens Unselected is possessed only by insect

Answers

Answer:

contains many individual light detectors, each with its own lens

Explanation:

The compound eye is found mainly in insects and crustaceans, it is composed of individual receptor units, each with its focus, sensing nerve; each one gives a small image of the environment, so the image is mosaic type, not a complete integral image of the environment.

When reviewing the different statements, the correct one is

contains many individual light detectors, each with its own lens

byeeeeeeeeeeeejdiiwidjwdjj2xi2idiwidisididie

Answers

Answer:

Be serious or else CEO of brainly will kick you out

What will happen to the velocity and momentum of each ball when the small ball hits the heavier large ball?

Answers

most of the momentum is transferred to the ball on top. Since the collision in this situation is elastic, momentum is conserved, meaning the momentum of both balls before hitting the floor is equal to the momentum of both balls right after the collision.

The small ball will transfer its momentum to the heavier ball. Since the momentum gets conserved. The velocity will depend upon the mass of the balls.

What is the law of conservation of momentum?

According to the law of conservation of momentum. The momentum of the body before the collision is always equal to the momentum of the body after the collision.

The momentum of the body is given by the product of the mass and velocity of the body.

According to the law of conservation of momentum

Momentum before collision =Momentum after collision

Hence the small ball will transfer its momentum to the heavier ball.

To learn more about the law of conservation of momentum refer;

https://brainly.com/question/1113396

which statement accurately describes how the acceleration of an object in free fall changes

Answers

Answer:

A ball rolls off the table and free falls to the ground. Which statement accurately describes its acceleration? Its acceleration is downward but remains a constant value as it falls.

Why are road accidents at high speeds very much worse than road accidents at low speeds?

Answers

Answer:

The momentum makes it worse.

Explanation:

The momentum of vehicles running at faster speeds is very high and causes a lot of damage to the vehicles.

Vehicles with high speeds have high momenta (plural of momentum). When they come to rest in very small time they experience high forces
we know that rate of change of momentum is force, lower the time higher is force. So, slow moving vehicles experience less force. It is important to note that if any one vehicle involving has high speed it can do more damage both the vehicles involving.

beansFe(aq) + Al(s) → beansAl(aq) + Fe(s) (7 points) a. What type of reaction is this? Explain what you think happened.b. This is also another type of reaction. What is it? Give another common example of this type of reaction.c. Do you think it is OK to eat the green beans? Explain why, or why not.

Answers

Answer:

tôi đoán lagf  pjhAWN ỨNG HÓA HỌC

Explanation:

After release of jet, energy is lost by the engine. How principle of conservation of energy is obeyed in this condition.​

Answers

Answer:

The principle of conservation of energy states that in a closed system, the energy can neither be created nor destroyed between interacting particles and remains constant or transformed from one form to another

In the jet engine, the release of jet changes the number of interacting particles in the engine, and given that energy cannot be created in the instantaneously closed system of the engine, energy is carried away and therefore lost by particles in the jet exhaust

The conservation of energy principle is therefore obeyed in the condition in which the jet engine losses energy by the release of jet

Explanation:

A man pulls his luggage on a 30 degree incline with a constant force of 25 N. How
much work does he do after walking 20.0 m?
a) 430 J
b) 330J
c) 1500J
d) 250 J

Answers

Force=F=25NDisplacement=s=20mAngle=30°

We know

[tex]\boxed{\sf W=Fscos\theta}[/tex]

[tex]\\ \sf\longmapsto W=25(20)cos30°[/tex]

[tex]\\ \sf\longmapsto W=500\times \dfrac{\sqrt{3}}{2}[/tex]

[tex]\\ \sf\longmapsto W=250\sqrt{3}[/tex]

[tex]\\ \sf\longmapsto W=250(1.73)[/tex]

[tex]\\ \sf\longmapsto W\approx 430J[/tex]

Option a) 430 J work done he do after walking 20.0 m.

What is work?

Work, in physics, is a measure of energy transfer that happens when an object exists moved over a distance by an external force at least part of which exists involved in the direction of the displacement.

Displacement exists as the distance moved in a straight line, in a provided direction, from the starting point. Displacement exists as a vector quantity as it includes size and direction.

An angle stands the figure formed by two rays, named the sides of the angle, sharing a standard endpoint, named the vertex of the angle.

Force=F=25NDisplacement=s=20mAngle=30°

⇒[tex]W=Fcos\theta[/tex]

⇒[tex]W=25(20)cos 30^{0}[/tex]

Then,

⇒[tex]W=50*\sqrt{3} /2[/tex]

⇒[tex]W=250\sqrt{3}[/tex]

Hence,

⇒[tex]W=250(1.73)[/tex]

[tex]W[/tex] approximately 430J.

Hence, Option a) 430 J work done he do after walking 20.0 m.

To learn more about Displacement refer to:

https://brainly.com/question/321442

#SPJ2

Una partícula efectúa un MAS cuya ecuación es: x=0,3 cos (2t + /6) m. Determinar: Amplitud, frecuencia angular, fase inicial, periodo, frecuencia de oscilación y posición en t=0,25 s

Answers

Answer:

The answer is below

Explanation:

Una partícula efectúa un MAS cuya ecuación es: x=0.3cos (2t + π/6) m. Determinar: Amplitud, frecuencia angular, fase inicial, periodo, frecuencia de oscilación y posición en t=0.25 s

Solution:

La ecuación de la onda es:

x = A cos (ω t + Ф), donde:

A = amplitud, ω = frecuencia angular = 2 π / T = 2 π f, Ф = fase inicial, f = frecuencia, T = período

Por lo tanto, comparando la ecuación de la onda con x = 0.3cos (2t + π / 6), obtenemos:

a) A = 0.3

b) ω = 2 rad / s

c) Ф = π / 6 rad

d) ω = 2π / T

2 = 2π / T

T = 3.14 s

e) ω = 2πf

2 = 2πf

f = 0.32 Hz

f) en t = 0.25 s:

x (t) = 0.3cos (2 * 0.25 + π / 6) = 0.22 m

A skipper on a boat notices wave crests passing his anchor chain every 5.6 s . He estimates the distance between wave crests to be 16 m . He also correctly estimates the speed of the waves. Find this speed.

Answers

Answer:

v = 2.85 m/s

Explanation:

Given that,

A skipper on a boat notices wave crests passing his anchor chain every 5.6 s.

The distance between wave crests to be 16 m.

We need to find the speed of the waves. The speed of a wave can be calculated by the formula as follows :

[tex]v=f\lambda\\\\v=\dfrac{\lambda}{T}\\\\v=\dfrac{16}{5.6}\\\\v=2.85\ m/s[/tex]

So, the speed of the wave is 2.85 m/s.

A water heater marked 4 kW takes 4 minutes to heat 1 kg of water from 20 °C to 50 °C. The cost of electrical energy per kWh
is $0.120. What will be the total cost of energy consumption?

Answers

The total cost of the energy consumption for the given time period is $0.0364

The given parameters include;

power rating of the heater, P = 4 kW = 4000 Wtime taken to completely boil the water,[tex]t = 4 \min = 4 \min \times \frac{1 \ h}{60 \ \min} = 0.067 \ h[/tex]mass of the water, m = 1 kginitial temperature of the water, t₁ = 20 ⁰Cfinal temperature of the water, t₂ = 50 ⁰Cspecific heat capacity of water, c = 4200 J/kg⁰Ccost of electrical energy = $0.12

The total energy consumed in the process of heating the water;

Total electrical Energy  = Energy of the heater (kWh) + Energy of the heated water (kWh)

Energy of the heater (kWh) = power x time

                                = 4 kW x 0.067 h

                                 = 0.268 kWh

Energy of the heated water (J) = mcΔt

where;

Δt is the change in temperature = t₂ - t₁

                                                      = 50 ⁰C  -  20 ⁰C = 30⁰C

Energy of the heated water (J) = 1 x 4200 x 30

                                               = 126,000 J

Electrical power of the heated water (Watts) = [tex]\frac{126,000 \ J}{4 \ \min} \times \frac{1 \min}{60 \ s} = 525 \ W[/tex]

Energy of the heated water (kWh) = [tex]\frac{525}{1000} \times 4\min\times \frac{1 \ hr}{60 \min} = 0.035 \ kWh[/tex]

Total electrical Energy  = 0.268 kWh  +  0.035 kWh

                                       = 0.303 kWh

The total cost of the energy consumed is calculated as;

[tex]Total \ cost = \frac{\$ \ 0.12}{kWh} \times 0.303 \ kWh = \$ \ 0.0364[/tex]

Therefore, the total cost of the energy consumption is $0.0364

To learn more about cost of electrical energy calculation, please visit: https://brainly.com/question/17924004

which is not a common theory on how the effects of hypnosis occurs

Answers

Answer:

EFFECTS Adverse reactions to hypnosis are rare, but may include: Headache. Drowsiness. Dizziness

A person slaps her leg with her hand, which results in her hand coming to rest in a time interval of 2.25 ms2.25 ms from an initial speed of 4.25 m/s4.25 m/s . What is the magnitude of the average contact force exerted on the leg, assuming the total mass of the hand and the forearm to be 1.75 kg1.75 kg

Answers

Answer:

The force is 3305.6 N.

Explanation:

Final velocity, v = 0

time, t = 2.25 ms

initial velocity, u = 4.25 m/s

mass, m = 1.75 kg

Let the acceleration is a.

Use first equation of motion.

v = u + a t

0 = 4.25 + a x 0.00225

a = - 1888.9 m/s^2

The force is

F = ma

F = 1.75 x 1888.9

F = 3305.6 N

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