If the actual frictional force is equal to 1 lb., then how much effort (force) would be required to drag a 90 lb. box up the plane?

A. 10+ lb.
B. 10- lb.
C.9+ lb.
D. 9- lb.

Could you also explain this? I am having a hard time understanding.

Answer:

A. the highest

Answer: Work Done would remain same.

Let us assume that the velocity is constant while taking the load up the inclined plane. Then, the kinetic energy would remain the same. This is because kinetic energy is dependent on velocity [tex](K.E.=\frac{1}{2}mv^2)[/tex]. If that is constant, the kinetic energy would remain same. The potential energy is dependent on the height[tex](P.E.=mgh)[/tex]. If the height is changed, then potential energy varies. In the question, it is mentioned that without changing the height, the length of the inclined plane is changed. Therefore, the potential energy would be same as before.

We know, work done is equal to potential energy plus kinetic energy. Since there is no change in any of these, the required work done would not change.

Answer:

a specialized species

Explanation:

Answer:

b

Explanation:

Kepler's third law allows finding the answers for the orbital speed of the planets are:

Kepler measured and analyzed the astronomical data of him and his tutor Brake, finding mathematical relationships that describe the movement of the planet, they are called Kepler's laws

      1. The orbits are ellipses

      2. A vector from the sun to the planet travels equal areas in equal times

      3. A relationship between the period and the semi-major axis of the orbit.

Kepler's third law is an application of Newton's second law to the motion of the planets around the sun.

Newton's second law establishes a relationship between force and the product of mass and acceleration of the object; in this case the force is the gravitational attractive force

           F = m a

           F = [tex]G \frac{M m}{r^2}[/tex]

Wher M y m are sum and planet mass, r is the distance ang G constnate universal gravitation

They indicate that we consider the orbits as circular, in this case the acceleration is centripetal

           a = [tex]\frac{v^2}{r}[/tex]

Let's substitute

         [tex]G \frac{M m}{r^2} = m \frac{ v^2}{r}[/tex]    

         [tex]v = \sqrt{ \frac{GM }{r} }[/tex]              (1)

The modulus of velocity (speed) is constant so we can use the uniform motion ratio

           v = [tex]\frac{\Delta x}{t}[/tex]

For a complete orbit, the distance traveled is the length of the circle and the time is called the period.

           Δx = 2π r

we substitute

            [tex]\frac{G M}{r} = \frac{4 \pi^2 r^2 }{T^2}[/tex]

            T² = ( [tex]\frac{4\pi ^2 }{GM}[/tex]) r³

They ask to calculate the orbital velocity we can use the relation 1

           v = [tex]\frac{\sqrt{GM }}{ \sqrt{r} }[/tex]

Let's find the value of the constant

           [tex]\sqrt{GM}[/tex] = [tex]\sqrt{6.67 \ 10^{-11} \ 1.991 \ 10^{30}}[/tex]

           [tex]\sqrt{GM} = 1.15 \ 10^{10}[/tex]

In the table we have the tabulated values ​​for the radii of the orbits of the planets

planet      radius orbit (m)    velocity (m/s)

Mercury       5.79 10¹⁰              4.779 10⁴

Venus          1.08 10¹¹               3.499 10⁴

Land            1,496 10¹¹             2,973 10⁴

Mars            2.28 10¹¹              2.408 10⁴

Jupiter        7.78 10¹¹               1.304 10⁴

Saturn         1.43 10¹²                9.62 10³

Uranus        2.87 10¹²               6.79 10³

Neptune     4.50 10¹²              5.42 10³

Pluto           5.91 10¹²               4.73 10³

We calculate the speed of some as an example and the others are in the third column of the table

Mercury

            v = [tex]\frac{1.15 \ 10^{10}}{\sqrt{5.79 \ 10^{10}} }[/tex]

            v = 4.779 10⁴ m / s

Venus

            v = [tex]\frac{1.15 \ 10^{10}}{\sqrt{1.08 \ 10^{11}} }[/tex]

            v = 3,499 10⁴ m / s

They ask to know the planet that has maximum and minimum orbital speed.

After reviewing the calculations, and observed the table,   Mercury has the highest speed and Pluto is the one with the lowest orbital speed.

When examining the expression the velocity is inversely proportional to the square root of the radius of the orbit

The radius of the orbit of Ceres is r = 2.766 ua  ( [tex]\frac{1.49 \ 10^{11} m}{1 ua}[/tex]) = 4.11 10¹¹ m

the orbital velocity of Ceres is

           v = [tex]\frac{1.15 \ 10^{10}}{\sqrt{4.11 \ 10^{11}} }[/tex]

           v = 1.79 10⁴ m / s

those that correspond to a speed between Mars and Jupiter

In conclusion using Kepler's third law we can find the answers for the orbital speed of the planets are:

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Answer:

increasing the heat under the pan will not raise the water temperature

increasing the heat under the pan will only evaporate water faster

Explanation:

i got this question too, these are the right answers

The correct choice is

D. Weathered rock fragments

For this case we have that a paper clip is a very small object, to be taken in the hand we feel that its mass is very small, almost imperceptible.

For this reason we can discard option D and option A.

Being so small we can use the milligrams to measure its mass, it is the smallest scale.

Answer:

Option B

Answer: Grams

Explanation: In the metric system, masses are measured using grams as the base unit. Prefixes can then be added to the base unit when appropriate.

Answer:

B

Explanation:

If you want to control the experiment, you want to make sure that no outside factor could potentially influence your results.

Hence, changing the diet of a hamster would significantly alter any results you may collect.

For example, if you allow hamster A to eat a nutritious diet, while not giving a proper diet to hamster B. Hamster A will perform better, and run further and for longer, because he has more energy.

The answer is B, because you want to make sure no hamster is at an advantage.

That is correct. Cognitive changes that accompany depression can include: Concentration, Memory, Decision-Making, Slowed Cognitive Processing, Negative Cognitive Bias, Rumination, Reduced Attention to Detail, Forgetfulness, Information Processing, Executive Function Impairment.

Difficulties in Concentration: People with depression often struggle to concentrate or focus on tasks, making it challenging to stay attentive and productive.

Memory Problems: Depressed individuals may experience difficulties with memory, both short-term and long-term, leading to forgetfulness and trouble recalling important information.

Impaired Decision-Making: Depression can affect a person's ability to make decisions, leading to indecisiveness, second-guessing, and avoidance of making choices.

Slowed Cognitive Processing: Cognitive processing speed may be reduced in individuals with depression, resulting in delayed responses and slower information processing.

Negative Cognitive Bias: Depression can lead to a negative cognitive bias, causing individuals to interpret situations in a pessimistic and negative manner, reinforcing feelings of hopelessness.

Rumination: Depressed individuals may engage in rumination, which involves obsessively dwelling on negative thoughts and feelings without finding resolution, leading to a cycle of negative thinking.

Reduced Attention to Detail: Depression can lead to a decreased ability to pay attention to details, impacting work, studies, and daily activities.

Forgetfulness: Depressed individuals may experience forgetfulness, leading to difficulties in remembering appointments, tasks, and important events.

Difficulty Processing Information: Depression may affect a person's ability to process and comprehend new information, making it challenging to learn and adapt.

Executive Function Impairment: Executive functions, such as planning, organization, and problem-solving, may be impaired by depression, making it difficult to manage daily responsibilities.

It's essential to remember that not everyone with depression will experience all of these cognitive changes, and the severity of these symptoms can vary from person to person. Seeking professional help and treatment for depression is crucial to address both the emotional and cognitive aspects of the condition. Early intervention can lead to better management of depression and its cognitive effects.

To know more about Rumination

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Complete question:- Cognitive changes that accompany depression include difficulties in concentration, memory problems, impaired decision-making, slowed cognitive processing, negative cognitive bias, rumination, reduced attention to detail, forgetfulness, difficulty processing information, and executive function impairment.

Satellites in the Global Positioning System (GPS) work together to provide navigation assistance via radio signals.

Satellites work together to aid in navigation in the Global Positioning System (GPS). GPS satellites broadcast radio signals that are used by GPS receivers to calculate precise positions on the Earth's surface. This calculation involves measuring the time it takes for the signals to travel from the satellite to the receiver, which allows the device to compute its distance from multiple satellites and thus pinpoints its location accurately.

Global Navigation Satellite Systems (GNSS) such as GPS, along with other international systems like Galileo, GLONASS, and BeiDou, provide critical Positioning, Navigation, and Timing (PNT) services, which are essential for various applications ranging from military operations to civilian uses like navigation and surveying.

Final answer:

The factors that affect the frictional force between objects include the roughness of the surfaces, adhesive forces between molecules, and the normal force pushing the objects together.

Explanation:

In physics, several factors affect the frictional force between objects. One factor is the roughness of the surfaces in contact. If the surfaces have more irregularities or peaks, more force is required to set the object in motion and maintain its motion. Another factor is the attractive forces between molecules making up the two objects. These adhesive forces depend on the substances the surfaces are made of, which explains why rubber-soled shoes slip less than those with leather soles. Finally, the normal force pushing the systems together also affects friction. Friction is proportional to the normal force.

Answer:

Explanation:

The real image is always inverted and can be obtained on a screen in this mode.

On the cinema screen, it now appears normal to our eyes.

Condensed light from the condenser goes through the film forming rays which are then passed through a series of lenses which spread them out and focus them on the screen.

The real image is what now shows on the screen.

The critical angle for light going from glycerin to air is approximately [tex]\( 42.47^\circ \)[/tex]

To calculate the critical angle for light going from glycerin to air, we need to use Snell's Law, which states:

[tex]\[ n_1 \sin \theta_1 = n_2 \sin \theta_2 \][/tex]

Where:

[tex]\( n_1 \)[/tex] is the refractive index of glycerin.

[tex]\( n_2 \)[/tex] is the refractive index of air.

[tex]\( \theta_1 \)[/tex] is the angle of incidence.

[tex]\( \theta_2 \)[/tex] is the angle of refraction.

The critical angle [tex](\( \theta_c \))[/tex] is the angle of incidence in the denser medium (glycerin) for which the angle of refraction in the less dense medium (air) is [tex]90[/tex] degrees. At the critical angle:

[tex]\[ \sin \theta_c = \frac{n_2}{n_1} \][/tex]

The refractive index of air [tex](\( n_2 \))[/tex] is approximately [tex]1[/tex]. The refractive index of glycerin [tex](\( n_1 \))[/tex] is approximately [tex]1.47[/tex]

Using these values:

[tex]\[ \sin \theta_c = \frac{1}{1.47} \][/tex]

Now, calculate [tex]\( \sin \theta_c \)[/tex]

[tex]\[ \sin \theta_c = 0.6803 \][/tex]

To find the critical angle [tex]\( \theta_c \)[/tex], take the inverse sine ([tex]arcsine[/tex]) of [tex]0.6803[/tex]

[tex]\[ \theta_c = \arcsin(0.6803) \][/tex]

Using a calculator

[tex]\[ \theta_c = 42.47^\circ \][/tex]

Divide the radius of the wheel by the radius of the axle

The change in potential energy of the book, moved from 1.2 m to 2.6 m above the ground, is 34.3 J.

Change in Potential Energy of a Book

To find the change in potential energy of the system containing the book and Earth, we use the formula for gravitational potential energy: PE = mgh, where m is the mass, g is the acceleration due to gravity (approximated as 9.8 m/s²), and h is the height.

First, calculate the initial potential energy of the book when it is at 1.2 m:

PEinitial = mghinitial

PEinitial = (2.5 kg)(9.8 m/s²)(1.2 m) = 29.4 J

Next, calculate the final potential energy of the book when it is at 2.6 m:

PEfinal = mghfinal

PEfinal = (2.5 kg)(9.8 m/s²)(2.6 m) = 63.7 J

The change in potential energy (ΔPE) is the difference between the final and initial potential energy:

ΔPE = PEfinal - PEinitial

ΔPE = 63.7 J - 29.4 J = 34.3 J

Thus, the change in the potential energy of the system is 34.3 joules.

Answer: concrete

Explanation: because of the absorption

(from Penn Foster) ⭐⭐⭐⭐⭐

Material                                             Coefficient of Absorption

Perforated acoustic ceiling material                               60%

Heavy curtains  (A)                                                             50%

Carpeting  (B)                                                                      20%

Wood  (C)                                                                              5%

Plaster                                                                                  3%

Clay tile (D)                                                                           3%

Concrete                                                                               2%

The answer is A. Heavy curtains ✅

Answer:

C

Explanation:

Just did it