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Anna35 [415]
3 years ago
5

When determining whether a chemical reaction has taken place, you observe and look for several indicators. Which would be consid

ered an indication that a chemical reaction or chemical change has taken place?
A) Solid melts.
B) Heat is given off.
C) Substance dissolves
D) Substance changes shape.
Physics
1 answer:
mixer [17]3 years ago
4 0
The answer would be B, heat is given off. Steam, bubbling, and fizzing can also indicate that a chemical change is occurring.  
You might be interested in
What kind of degree does an ultrasound tech. need?
Anna11 [10]
<span>Educational Requirements. Training to become an ultrasound technician can be done through a formal education program or through military training. The most common training is an associate's degree program, although there are bachelor's degree and 1-year certificate programs available.</span>
7 0
3 years ago
A hill that has a 15.5% grade is one that rises 15.5 m vertically for every 100.0 m of distance in the horizontal direction. At
Andreas93 [3]

The angle of incline of the hill above the horizontal is 8.81°.

Since the hill has a 15.5% grade is one that rises 15.5 m vertically for every 100.0 m of distance in the horizontal direction.

<h3>Tangent of the angle of the incline of the hill,</h3>

The tangent of the angle of the incline of the hill, Ф is

tanФ = vertical rise/horizontal distance = grade of hill

Now, the vertical rise = 15.5 m and the horizontal distance = 100.0 m

So, substituting the values of the variables into the equation, we have

tanФ = vertical rise/horizontal run

tanФ = 15.5 m/100.0 m

tanФ = 0.155

<h3>Angle of incline of the hill</h3>

Taking inverse tan of both sides, we have

Ф = tan⁻¹(0.155)

Ф = 8.81°

So, the angle of incline of the hill above the horizontal is 8.81°.

Learn more about angle of incline of a hill here:

brainly.com/question/10056962

6 0
2 years ago
ANSWER ALL QUESTIONS AND GET 100 PONTS ALONG WITH BRAINLIEST
dmitriy555 [2]

Answer:

  • To not exceed the 5,000 characters, see each answer with its explanation below.

Explanation:

<u><em>Question 1.</em></u>

<em>A feather and a rock dropped at the same time from the same height would land at the same time when dropped by an astronaut on the moon</em>.

The shape and mass of the <em>feather</em> that falls vertically down, through the air, cause the resistance of the air, that opposes the gravitational attraction of the Earth, to be considerably large, compared to the case of the <em>rock</em>.

This not negligible resistance of the air causes a drag on the <em>feather</em> that makes it fall more slowly than the <em>rock</em>.

Only on the moon, the almost absence of atmosphere (air) would cause the <em>feather</em> not to be dragged and, therefore, its acceleration will be the same as that of the rock, and both will fall with the same speed and land at the same time (there is a video in the internet that shows this experiment of the astronaut on the moon).

<em><u>Question 2.</u></em>

<em>When the soccer ball is kicked, the action and reaction forces do not cancel each other out because the forces act on two different objects.</em>

The third law of Newton, also known as the law of action and reaction, states that whenever an object experience a force (action force) from a second object, the first object will exert a force of equal size and opposite in direction (reaction force) over the second object.

Hence, the action and reaction forces act over distinct objects. The ball feels the action force (the kick) and the foot feels the reaction force from the ball; the forces do not cancel each other because they act on two different objects.

<u><em>Question 3 </em></u>

<em>An object is in projectile motion if it is thrown with a horizontal push.</em>

The <em>projectile motion</em> is the combination of two motions: vertical motion and horizonal motion.

The vertical motion is ruled by the acceleration of gravity and will depend on both the inital vertical velocity and the acceleration of gravity.

The horizontal motion is ruled by the horizontal velocity. According with the inertia law (first law of Newton), in the absence of a horizontal force, only if the object departs with a horizontal velocity it will move horizontally.

Hence, an object can only be in projectile motion if it is thrown with a horizontal push.

<u><em>Question 4 </em></u>

Acceleration of an object

  • increases as the force on the object increases.
  • decreases as the mass of the object increases.
  • is in the same direction as the force on the object.
  • All answers listed.    ← correct answer

According to second law of Newton

          \vec{F}=m\times \vec{a}

This is force equals mass time acceleration.

The force is a vector and the acceleration is a vector, then since mass is a positive scalar magnitude, both force and acceleration have the same direction.

Also, it is clear from the definition of force that it is proportional to both, the mass and the acceleration, then if either mass or acceleration increases (while the other remains equal) the force will increase, and if either mass or acceleration decreases (while the other remains constant) the force will decrease.

Hence, all the options are correct.

<u><em>Question 5</em></u>

<em>The bowling ball will have more momentum because it has more mass.</em>

Momentum, P, is the product of the mass (m) and the velocity (v).

           \vec{P}=m\times \vec{v}

It is clear that the mass of the bowling ball is greater than the mass of the golf ball.

Hence, since they are moving at the same velocity, the product of the mass of the bowling ball times the velocity is greater than the product of the golf mass times the same velocity.

<u><em>Question 6</em></u>

<em>An  </em><em><u>   orbit         </u></em><em> is formed when an object is falling around another object, rather than into it.</em>

An example of an object falling around another object is a rock falling in the Earth. The gravitaional pull of the Earth causes that the rock accelerates and falls vertically downward.

An example of an object falling around another object is a satellite around the Earth.

The Earth is continually pulling the satellite with vertical force and the inertia (initial velocity) of the satellite is causing it to move horizontally.

The combination of the gravitational force and the inertia cause the satellite to follow a projectile motion. When the satellite is to the correct distance it will not reach into the Earth but will continually move around the Earth following a circular path named orbit.

<u>Question 7</u>

<em>When the force of gravity is matched by the force of air resistance, an object can reach  </em><em><u>    terminal velocity      </u></em><em>(two word answer).</em>

When the force of gravity matches the force of air resistance, the net force on the falling object is zero.

Hence, as per the second Law of Newton, force equals the product of the mass and the acceleration, the acceleration is also zero.

Zero acceleration means constant velocity.

That constant velocity is a limit or maximum for the velocity that an object can reach when falling and is called terminal velocity.

3 0
3 years ago
Two charged particles, with charges q1=q and q2=4q, are located at a distance d= 2.00cm apart on the x axis. A third charged par
Murrr4er [49]

Answer:

X₃₁ = 0.58 m  and  X₃₂ = -1.38 m

Explanation:

For this exercise we use Newton's second law where the force is the Coulomb force

        F₁₃ - F₂₃ = 0

        F₁₃ = F₂₃

Since all charges are of the same sign, forces are repulsive

        F₁₃ = k q₁ q₃ / r₁₃²

        F₂₃ = k q₂ q₃ / r₂₃²

Let's find the distances

         r₁₃ = x₃- 0

         r₂₃ = 2 –x₃

We substitute

      k q q / x₃² = k 4q q / (2-x₃)²

      q² (2 - x₃)² = 4 q² x₃²

        4- 4x₃ + x₃² = 4 x₃²

        5x₃² + 4 x₃ - 4 = 0

We solve the quadratic equation

        x₃ = [-4 ±√(16 - 4 5 (-4)) ] / 2  5

        x₃ = [-4 ± 9.80] 10

       X₃₁ = 0.58 m

       X₃₂ = -1.38 m

For this two distance it is given that the two forces are equal

7 0
3 years ago
A 44-turn rectangular coil with length ℓ = 17.0 cm and width w = 8.10 cm is in a region with its axis initially aligned to a hor
Mumz [18]

Answer:

The maximum induced emf in the rotating coil  = 29.66V

The induced emf in the rotating coil when (t = 1.00 s) = 26.66V

The maximum rate of change of the magnetic flux through the rotating coil = 0.674Wb/s

Explanation:

Lets state the parameters we are being given right from the question:

Number of rectangular coil, (N) = 44

Length of Coil, l =17cm in meters we have; (l) = 17 × 10⁻² m

Width of Coil, w =8.10cm in meters we have; (w) = 8.10 × 10⁻² m

Magnitude of Uniform Magnetic Field (B) = 767mT= 765 × 10⁻³ T

Angular Speed of Coil, (ω) = 64 rad/s

(a)

To calculate the induced emf in the rotating cell,we can use the formula:

emf = NBAωsin(ωt)

For maximum induced emf, the value of sin(ωt) will be 1

emf_max = NBAω ; if (A = l × w) , we have:

emf_max  = NB(l × w)ω

subsitituting the parameters into the above equation; we have:

emf_max  = 44 × 765 × 10⁻³ ( 17 × 10⁻² × 8.10 × 10⁻² ) × 64

= 29.66V

(b)

At t = 1s, the induced emf is calculated as:

emf = NBAωsin(ωt)

substituting the parameters into the equation, we have:

emf =   44 × 765 × 10⁻³ ( 17 × 10⁻² × 8.10 × 10⁻² ) × 64 × sin (64 × 1)

=26.66V

(c)

To calculate the maximum rate of change of the magnetic flux through the rotating coil; we need to reflect on the equation for the maximum induced emf in terms of magnetic flux.

i.e emf_max = N\frac{d∅}{dt}

since emf_max = 29.66 and N = 44; we have:

29.66 =  44\frac{d∅}{dt}

\frac{d∅}{dt} = \frac{29.66}{44}

= 0.674 Wb/s

5 0
3 years ago
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