7. Which phase changes require a gain of energy (heat)?
a. melting and freezing
b. sublimation and vaporization
c. vaporization and condensation
d. sublimation and deposition

Atlantic Ocean (salt water)

Answer:

Answer:

The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.

Explanation:

Answer: The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.

Answer:

198.20 N

Explanation:

Given that,

Mass of a heavy bag, m = 25 kg

The bag is attached to the ceiling until it makes an angle of 36 degrees to the vertical.

We need to find the force must the boxer exert on the bag. The force acting on the bag is given by :

[tex]F=mg\cos\theta\\\\=25\times 9.8\times \cos(36)\\\\=198.20\ N[/tex]

So, the required force is 198.20 N.

Answer:

a. They are typically operated at lower temperatures.

a. They are typically operated at lower temperatures.b. They are especially helpful for viewing cool or obscured astronomical objects.

Answer:

A magnet would be the answer

Answer:

QESARDFRGTSRTATFREVERSRvrvqwqv

Explanation:

vfqfvcafbraf w rfdsd AEWvd a

The earth receives energy from the sun in one day than all the energy consumed by humans in one year.

The sun provides around 174 petawatts of energy to Earth, of which 89 petawatts is absorbed by the planet.

The Global energy consumption is roughly 15 terawatts annually.

Thus, we can conclude that, the earth receives energy from the sun in one day than all the energy consumed by humans in one year.

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Answer:

0

Explanation:

the block is being pulled at a constant velocity meaning it has no acceleration. the rule is fnet=mass x acceleration so if theres no acceleration there is no force net!

A block of mass 2 kg is pulled across a surface with a force of 15 N then the net force acting on the block is 0.

A force is an effect that can alter an object's motion according to physics. A force might cause an object has mass to accelerate when it changes its velocity, for, us when it moves away from rest. An obvious way to describe force is in terms of push or pull. A force is a vector quantity since it has equal magnitude and direction. It is calculated using the newton SI unit (N). Force is denoted by the letter F.

The net force exerted by an object was equal to the speed at which its velocity varies over time, according to Newton's second law in its original formulation.

The block has no acceleration because it is being pushed at a constant speed. If there is no acceleration, there is no force net because the formula is net force =mass × acceleration.

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There's a constant force of 35 N exerted on the object of mass 2.0 kg, so it undergoes an acceleration a of

35 N = (2.0 kg) a   →   a = 17.5 m/s²

The object travels 8.0 m, so that it attains a velocity v of

v ² = 2 (17.5 m/s²) (8.0 m)   →   v ≈ 16.73 m/s ≈ 17 m/s

The velocity of the 2 Kg object which travels 8 m along the horizontal frictionless surface is 17 m/s

a = F / m

a = 35 / 2

a = 17.5 m/s²

v² = u² + 2as

v² = 0² + (2 × 17.5 × 8)

v² = 280

Take the square root of both side

v = √280

v = 17 m/s

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Answer:

kinetic energy increases with the energy which causes the particles to move faster resulting in increases collision rates and rate of diffusion.

Explanation:

The increase in temperature of the air causes the air molecules to have more kinetic energy, which leads to more frequent and forceful collisions with the smoke particles. This, in turn, causes the smoke particles to move faster through the air.

Kinetic energy is the energy an object possesses due to its motion. Any object that is in motion has kinetic energy, and the amount of kinetic energy it has depends on its mass and velocity.

The formula for calculating kinetic energy is:

KE = 1/2 ×  m × v²

where KE represents kinetic energy, m represents the mass of the object, and v represents the velocity of the object.

Here in the question,

Smoke particles in the air move around due to collisions with air molecules. When the temperature of the air increases, the average kinetic energy of the air molecules also increases. This means that the air molecules are moving faster and colliding more frequently with the smoke particles.

The smoke particles themselves do not have an increase in kinetic energy, but they do receive more energy from the collisions with the air molecules. This extra energy causes the smoke particles to move faster and more erratically, making them more dispersed throughout the air.

In addition, when air is heated, it becomes less dense. This means that there are fewer air molecules in a given volume of air. As a result, the smoke particles have more space to move around and collide with air molecules, which further contributes to their increased speed and movement.

Therefore, increasing the temperature of the air increases the speed and frequency of collisions between the air molecules and smoke particles, leading to the smoke particles moving faster and more widely dispersed throughout the air.

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Answer:

The answer is 494.9 N

Explanation:

I got this same question, and it worked for me! Hope this helps <3

Answer: Wind follows a pattern because the Earth is spinning in one motion. If we were spinning in one way then another we would have one day go by then the spinning cycle would change and we would have to go through that day all over again, it would not be logical because then we would be in the same season as well, we would be in one season for the rest of our lives until we died.

I don't know if this was helpfull or not but I hope it was somewhat close to helpful? If it is not then please do not report this, I am sorry if this was the least bit helpful.

HAVE A NICE DAY! :)

Answer:

p=w/t

160/8=20

80/4=20

180/9=20

...so..all these uses equal power

Answer: [tex]5.64\ m/s^2[/tex]

Explanation:

Given

mass of sled m=5 kg

Elevation [tex]\theta =45^{\circ}[/tex]

[tex]\mu _k=0.185[/tex] (coefficient of kinetic friction)

Friction will oppose the motion of the sled while sled weight sin component helps it to move down the incline

[tex]W\sin\theta-F_r=ma\\where\\W=weight(mg)\\F_r=Friction(\mu_kmg\cos\theta)\\a=acceleration[/tex]

Substituting values

[tex]mg\sin \theta-\mu_kmgcos\theta=ma\\g\sin \theta-\mu_kg\cos \theta=a\\a=g(\sin 45^{\circ}-0.185\times \cos 45^{\circ})\\a=5.64\ m/s^2[/tex]

Answer:

27.1m/s

Explanation:

Given parameters:

Height of the building  = 30m

Initial velocity  = 12m/s

Unknown:

Final velocity  = ?

Solution:

We apply one of the kinematics equation to solve this problem:

         v²  = u²  + 2gh

v is the final velocity

u is the initial velocity

g is the acceleration due to gravity

h is the height

          v²   = 12²  + (2 x 9.8 x 30)

          v  = 27.1m/s

Answer:

The body becomes a positive charged body.

Explanation:

Given that two objects are shown below. One is neutral and the other is negative. What do you predict would happen?

According to the law of static electricity, like charges repel each other while unlike charges attract each other.

Since one of the object is neutral and the other one is negative, there will neither attraction nor repulsion between them.

Also, according to Electrostatic induction, the neural body can be charged and becomes positive.

The negative body will attract all the positive charges to its side, and repel all the negative charges to the other side. If the body is touched at the other end, the whole negative charges will be earthed and the body will become a positive body.

Answer:

measurable period during which an action, process, or condition exists or continues

Explanation:

Answer:

Time is the indefinite continued progress of existence and events that occur in an apparently irreversible succession from the past, through the present, into the future.

Explanation:

hope it helps...

Answer: I'm like 98% sure it's fluorescent cause it's got mercury

Explanation:

Answer:

14.8J

Explanation:

PE=MGH

M=0.21

G=9.8m/s

H= 7.2 m

0.21x7.2x9.8= 14.8176 J

Answer:

Technique of comparing abundance ratio between radioactive isotopes to a reference isotope to determine the age of a material called radioactive dating. It determines the age by having a more abundance of isotopes in the cellular being.

Answer:

Acids break down fabrics and can cause burns if the acids are strong.

Explanation:

A protective apron or lab coat is important when working with acids because acids break down fabrics and can cause burns if the acids are strong.

Answer:

C

Explanation:

I got it right

Given :

An object with a volume of 9 cm³ is completely submerged in the water.

To Find :

How much water is displaced by the object.

Solution :

According to Archimedes' principle, the amount of volume displaced of fluid when an object is fully and partially submerged into that is equal to the volume of the object below the surface of liquid.

Now, it is given that object is fully submerged into water.

Therefore, volume of water displaced by the object is 9 cm³.

Answer:

3040 m

Explanation:

The formula to apply here is ;

d=∅*r  where

d is the diameter of the spot , ?

∅ is angle of divergence in radians, = 0.8 * 10⁻⁵rad

r is distance of Moon from Earth, =380,000 km

Applying the formula as;

d=∅*r

d= {0.8 *10⁻⁵} * 380,000 * 1000

d= 3040 m

Answer:

your answer will be the letter B

Answer:

A force has both Direction and Motion.

Explanation:

For example, when finding acceleration you take the time and divided it by distance. If the thing you are measuring is going in the positive direction, the acceleration will be positive and if it is going in the negative direction the acceleration will be negative.

Magnitude and Direction

Explanation:

Force is a Vector Quantity

As learned in an earlier unit, a vector quantity is a quantity that has both magnitude and direction. To fully describe the force acting upon an object, you must describe both the magnitude (size or numerical value) and the direction.

Answer:

5.6x10^4

Explanation:

use the equation V=kq/d

k is the constant 8.99x10^9

V=(8.99x10^9)q/d

q is the charge, 7.5 micro coulombs, but to get coulombs, multiply by 10^-6

V=(8.99x10^9)(7.5x10^-6)/d

And from the problem, we know that the distance is 1.2 meters

V=(8.99x10^9)(7.5x10^-6)/1.2

This simplifies to 5.6x10^4

The electric potential is 5.6 x 10⁴ v.

To find the electric potential the distance = 1.2 m

Charge q = 7.5 UC

               The amount of work needed to move a unit charge from the known point to some unknown point against the electric field  is said to be electric potential.

Formula of an electric potential is

                                     V = k ( q/r)  volt

                   V - electric potential

                    k - Coulomb constant (8.99x10^9)  

                    q -  charge

                     r- distance of separation

  V = (8.99x10⁹) (q/d)

  q = 7.5 UC ( micro coulomb) 10⁻⁶ C

   V=(8.99x10⁹)(7.5x10⁻⁶)/d

Substituting the values,

    V=(8.99x10⁹)(7.5x10⁻⁶)/1.2

    V = 5.6x10⁴ v

Thus, option A is correct.

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Answer:

Hmmm

Explanation:

Here what I know... If a function gives the position of something as a function of time, the first derivative gives its velocity, and the second derivative gives its acceleration. So, you differentiate position to get velocity, and you differentiate velocity to get acceleration. where t is in seconds and H(t) is in inches.

Does this help?

Answer:

Scientists predict that sea levels could rise up to six-feet by 2100. An increase this large will swallow beaches—impacting public access, beach recreation, and healthy ecosystems. ... With less sand beach-goers will have a completely different recreational experience in the future.

Explanation: