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3 years ago

Consider the following True/False statements:

Physics

1 answer:

Ainat [17]3 years ago

4 0

Answer:

6) False

7) True

8) False

9) False

10) False

11) True

12) True

13) True

14) True

Explanation:

The spacing between two energy levels in an atom shows the energy difference between them. Clearly, B has a greater value of ∆E compared to A. This implies that the wavelength emitted by B is greater than A while B will emit fewer, more energetic photons.

When atoms jump from lower to higher energy levels, photons are absorbed. The kinetic energy of the incident photon determines the frequency, wavelength and colour of light emitted by the atom.

The energy level to which an atom is excited is determined by the kinetic energy of the incident electron. As the voltage increases, the kinetic energy of the electron increases, the further the atom is from the source of free electrons, the greater the required kinetic energy of free electron. When electrons are excited to higher energy levels, they must return to ground state.

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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:

Question 1.

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.

The shape and mass of the feather 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 rock.

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

Only on the moon, the almost absence of atmosphere (air) would cause the feather 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).

Question 2.

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.

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.

Question 3

An object is in projectile motion if it is thrown with a horizontal push.

The projectile motion 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.

Question 4

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.

Question 5

The bowling ball will have more momentum because it has more mass.

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.

Question 6

An orbit is formed when an object is falling around another object, rather than into it.

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.

Question 7

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

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

Dwayne ‘The Rock’ Johnson needs to escape from the fourth floor of a burning building (in a movie). He ties a rope around his wa

ZanzabumX [31]

Answer:

Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s

Explanation:

Let's start out with finding the force acting downwards because of the mass of 'The Rock':

Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N

Now the problem also states that the kinetic friction of the desk in this problem is 370 N

Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N

Now lets use F = ma to calculate for the acceleration of the desk:

787.58 = 63 x acceleration

acceleration = 12.501 m/s

Finally, we can use the motion equation:

$v^2 - u^2 = 2*a*s$

here u = 0 m/s (since initial speed of the desk is 0)

a = 12.501 m/s

and s = 10 m

Solving this we get:

$v^2 - 0 = 2 * 12.501 * 10$

$v = 15.812 m/s$

Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.

5 0

3 years ago

A packing crate rests on a horizontal surface. It is acted on by three horizontal forces: 600 N to the left, 200 N to the right,

egoroff_w [7]

Answer:

The resultant force would (still) be zero.

Explanation:

Before the 600-N force is removed, the crate is not moving (relative to the surface.) Its velocity would be zero. Since its velocity isn't changing, its acceleration would also be zero.

In effect, the 600-N force to the left and 200-N force to the right combines and acts like a 400-N force to the left.

By Newton's Second Law, the resultant force on the crate would be zero. As a result, friction (the only other horizontal force on the crate) should balance that 400-N force. In this case, the friction should act in the opposite direction with a size of 400 N.

When the 600-N force is removed, there would only be two horizontal forces on the crate: the 200-N force to the right, and friction. The maximum friction possible must be at least 200 N such that the resultant force would still be zero. In this case, the static friction coefficient isn't known. As a result, it won't be possible to find the exact value of the maximum friction on the crate.

However, recall that before the 600-N force is removed, the friction on the crate is 400 N. The normal force on the crate (which is in the vertical direction) did not change. As a result, one can hence be assured that the maximum friction would be at least 400 N. That's sufficient for balancing the 200-N force to the right. Hence, the resultant force on the crate would still be zero, and the crate won't move.

6 0

3 years ago

1) How many AU make up a light-year?

MrRissso [65]

Answer:..

1.One light-year = 63,240 AU

2. It’s about 93 million miles (150 million km),or

one astronomical unit (AU) = 92,955,807 miles (149,597,871 km).

8 0

3 years ago

Read 2 more answers

Equation for inclined spring

zalisa [80]

Answer:

dbdbdheh eewr h eahehwGFTT5Q3JFX

Explanation:

FJGXJDGTFJSRRXAGFEWFWDdQDE

6 0

3 years ago