The lower the percent of energy required for a machine to perform work, the more energy efficient it is. Please select the best answer from the choices provided T F

The total work done by the donkey to pull the cart out of the mine is calculated by finding the work done against gravity and friction. The work done against gravity is 37012.5 J and against friction is 11637.5 J. The sum, and thus the total work done, is 48650 J.

To find the total work done by the donkey, we need to consider the work done against both the gravitational force and the frictional force. The total work done will be equal to the sum of these two works.

Firstly, let's find the work done against the gravitational force. The force of gravity acting on the cart can be found using the equation F = m x g x sin(θ), where m is the mass of the cart, g is the acceleration due to gravity, and θ is the angle of the slope. Therefore, F = 413 kg x 9.81 m/s² x sin(4.69°) = 211.5 N. The work done against gravity is then W = F x d, where d is the distance the cart is hauled, resulting in W = 211.5 N x 175 m = 37012.5 J.

Secondly, let's calculate the work done against friction. The frictional force can be found using the equation F = μ x m x g x cos(θ), where μ is the coefficient of friction. Therefore, F = 0.0163 x 413 kg x 9.81 m/s² x cos(4.69°) = 66.5 N. The work done against friction is again W = F x d, giving W = 66.5 N x 175 m = 11637.5 J.

The total work done by the donkey is then the sum of these two works, giving 37012.5 J + 11637.5 J = 48650 J.

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The direction of the centripetal force when applied to an object is perpendicular to the object's motion.

Any motion along a curved road is accelerated, necessitating the application of force to the path's center of curvature. This force is known as the centripetal force, which is a force that seeks its center.

The direction of centripetal force, or even net force, is always that of acceleration. As an illustration, consider how quickly the earth is moving toward the sun. We are not moving toward the sun since the acceleration vector for planet Earth is constantly pointing in that direction and the velocity is perpendicular to it.

When force applied to an item, the centripetal force's direction is perpendicular to the object's motion.

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The correct answer would be B. To provide support for a weakened joint. I just took the test!

Final answer:

The roller coaster's speed at the top of the loop is calculated using the centripetal acceleration formula, with the given downward acceleration of 1.50 g which equals 14.7 m/s² and the radius of curvature of 11.0 m to find the velocity.

Explanation:

The speed of the roller coaster at the top of the loop can be determined by utilizing the concept of centripetal acceleration. Centripetal acceleration is provided by the gravitational force when the roller coaster is at the top of the loop. Given that the downward acceleration is 1.50 g, and knowing that 1 g equals 9.8 m/s2, we can calculate the centripetal acceleration as 1.50 times 9.8 m/s2. The formula for centripetal acceleration (ac) is ac = v²/r, where v is the velocity and r is the radius of curvature. Rearranging the formula to solve for v gives us v = √(ac × r). Plugging in the values, we have v = √((1.50 × 9.8 m/s2) × 11.0 m), which yields the speed of the roller coaster at the top of the loop.

Final answer:

To find Neil's velocity relative to Barbara, their individual velocities are considered as vectors and subtracted. Neil's relative velocity is calculated to be approximately 6.74 m/s at 69° north of west.

Explanation:

To determine Neil's velocity relative to Barbara, we need to consider both Neil’s and Barbara's velocities as vectors and subtract the velocity of Barbara from Neil's velocity. Barbara is moving due south at 6.3 m/s, and Neil is moving due west at 2.4 m/s. By defining south as the negative y-direction and west as the negative x-direction, we can represent Barbara’s velocity vector as (0 m/s, -6.3 m/s) and Neil's as (-2.4 m/s, 0 m/s).

To find Neil’s velocity relative to Barbara, we calculate the vector difference: Neil’s velocity minus Barbara's velocity:

VNB = VN - VB = (-2.4 m/s, 0 m/s) - (0 m/s, -6.3 m/s) = (-2.4 m/s, 6.3 m/s)

To find the magnitude of Neil's relative velocity (VNB), we use the Pythagorean theorem: |VNB| = √((-2.4 [tex]m/s^2[/tex] + (6.3 [tex]m/s^2[/tex]), which gives:

|VNB| = √(5.76 + 39.69) = √(45.45) ≈ 6.74 m/s

The direction relative to due west can be found using the arctangent of the y-component over the x-component:

θ = arctan(6.3 / 2.4) ≈ arctan(2.625) ≈ 69°

Therefore, Neil's velocity relative to Barbara is approximately 6.74 m/s at an angle of 69° north of west.

The correct answer would be letter d, 8.3.

Solution for the problem follows:

Given are:

B = 6i - 8j 

A is unknown; let A be = mi + nj 

A+B is along the x axis (therefore A+B = Ki + 0j, where K is unknown,

but then again the magnitude of A+B is the similar as the magnitude of A,

so mag(A+B)=K=sqrt(m^2+n^2), or K^2 = m^2+n^2. 

A+B, from simple vector addition, will be now (m+6)i + (n-8)j.

Ever since we previously know A+B = Ki + 0j, we now know that: 

m+6 = K 

n-8 = 0, which implies n=8. 

Thus, K^2=m^2+n^2 ====> (m+6)^2 = m^2 +8^2 

= m^2 + 12m + 36 = m^2 + 64 

= 12m = 28 

= m = 2.33333... 

Therefore, the magnitude of A is sqrt[(2.333...)^2 + 8^2] = 8.3333

The magnitude of [tex]\vec A[/tex] is [tex]8.3[/tex].

Further explanation:

A vector is a quantity having magnitude and direction both. It is represented as the product of magnitude and direction vector.

Given:

The vector is given as [tex]\vec B = 6\hat i - 8\hat j[/tex].

The direction of resultant vector is in the X- direction.

Concept used:

Consider a vector [tex]\vec A = a\hat i + b\hat j[/tex] which is added to [tex]\vec B[/tex] to get a resultant vector [tex]\vec C[/tex]. The resultant vector is directed in the positive X-direction which means that the y- component of the vector is zero.

The expression for the resultant vector is given as.

[tex]\vec C = \vec A + \vec B[/tex]

Substitute [tex]6\hat i - 8\hat j[/tex] for [tex]\vec B[/tex] in the above expression.

[tex]\begin{gathered}\vec C = \left( {a\hat i + b\hat j} \right) + \left( {6\hat i - 8\hat j} \right) \\= \left( {a + 6} \right)\hat i + \left( {b - 8} \right)\hat j \\ \end{gathered}[/tex]

The resultant vector is represented as.

[tex]\vec C = x\hat i + 0\hat j[/tex]

Compare the above two expression of resultant vector.

[tex]x = a + 6[/tex]                                         …… (1)

[tex]\begin{aligned}0&=b-8\\b&=8\\\end{aligned}[/tex] 

The magnitude of resultant vector is equal to the magnitude of [tex]\vec A[/tex].

The expression for the magnitude of [tex]\vec A[/tex] is given as.

[tex]\left| {\vec A} \right| = \sqrt {\left( {{a^2}} \right) + \left( {{b^2}} \right)}[/tex]                           …… (2)

The expression for the magnitude of [tex]\vec C[/tex] is given as.

[tex]\left| {\vec C} \right| = \sqrt {{{\left( {a + 6} \right)}^2}}[/tex]

Compare the above two expressions.

[tex]\sqrt {\left( {{a^2}} \right) + \left( {{b^2}} \right)}= \sqrt {{{\left( {a + 6} \right)}^2}}[/tex]

Substitute 8 for [tex]b[/tex]  in above expression.

[tex]\begin{aligned}\sqrt {\left( {{a^2}} \right) + \left( {{8^2}} \right)}&=\sqrt {{{\left( {a + 6} \right)}^2}}\\{a^2} + 64&={a^2} + 36 + 12a \\12a&=28 \\a&=2.33 \\ \end{aligned}[/tex]

Substitute 2.33 for a and 8 for b in equation (2).

[tex]\begin{aligned}\left| {\vec A} \right|&=\sqrt {{{\left( {2.33} \right)}^2} + {{\left( 8 \right)}^2}}\\&=8.33 \\ \end{aligned}[/tex]

Thus, the magnitude of vector A is [tex]8.33[/tex].

Learn more:

1.  Motion under friction https://brainly.com/question/7031524.

2.  Conservation of momentum https://brainly.com/question/9484203.

3. Circular motion https://brainly.com/question/9575487.

Answer Details:

Grade: College

Subject: Physics

Chapter: Vectors

Keywords:

Vectors, product, magnitude, direction, resultant vector, adding vector, subtraction of vector, 2.33, 8, 8.33, 8.3, 8.33.

The electric flux through this area:

This is defined as the number of electric field lines that intersect a given area.

Electric flux(φ)= EA cos θ

where θ = angle between the directions of E and A is the surface area.

When the electric field is perpendicular to the surface,  θ = 0°.

φ = EA cos(0°)  = (6.20 x 10⁵ N/C)*(3.2 m²) × 1 = 1.984 x 10⁶ Nm²/C

When the electric field is parallel to the area, then θ = 90°, and

φ = EA cos(90°) = 0 as result of cos 90° being zero.

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Without the given Figure, precise answers can't be provided. Generally, acceleration is calculated as the slope of the velocity-time graph, and position is provided by the integral (or area under the graph) of the velocity-time graph. The object's speed is lowest when its velocity is minimal, and it is farthest from x= 0 when the accumulated area under the graph is maximum.

Unfortunately, without the given Figure P2.50, it's impossible to accurately calculate the object's acceleration, position at different times, or specify when the object is moving with the lowest speed or is farthest from x = 0.

However, I can explain the general method to determine this information. Acceleration is calculated from the slope of the velocity-time graph. The position is generally obtained by calculating the area under the velocity-time graph from the beginning of the interval to the end. The object is moving with the lowest speed when the velocity is lowest (either positively or negatively). The object is farthest from x = 0 when the accumulated area under the velocity-time graph (counting areas below the time axis as negative) is a maximum. The total distance the object has moved is equal to the absolute sum of all the areas (both positive and negative) on the velocity-time graph.

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Answer:B,C, They cannot tell the difference between people and other objects. & They will wait for crossing pedestrians even if signaled to keep driving.

Explanation: i just did it on edg

Driverless cars can disrupt traffic due to slow speeds and over-caution, struggle to differentiate between people and objects, unexpectedly move to avoid hazards, and may not allow human control in emergency situations.

Driverless cars, or autonomous vehicles, have several disadvantages that might affect their performance and usability. Firstly, these vehicles often operate at safer, slower speeds than typical road traffic, which can disrupt normal traffic flow. Secondly, while they use advanced sensors to detect their surroundings, they might struggle to differentiate between people and other objects. This could potentially lead to harmful incidents. Additionally, they might be overly cautious and halt for crossing pedestrians even when it's unnecessary, causing further disruption.

Moreover, unpredictable actions like veering off the road to circumvent hazards could pose risks to passengers or other vehicles. Lastly, a key issue is if these vehicles don't permit the human driver to override control manually in crisis situations, which can decrease the human's ability to avert dangerous situations.

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Final answer:

The question requires calculating the rate at which two individuals are moving apart by using their speeds and applying principles of kinematics. It involves converting time into seconds, calculating the total distance each person traveled, and then finding the distance between them 15 minutes after the woman starts walking.

Explanation:

The question involves calculating the rate at which two people are moving apart from each other, given their speeds and initial positions. It requires an understanding of relative motion and the ability to apply the principles of kinematics to solve real-world problems.

The man starts walking north from a point P at 2 ft/s, and five minutes later, a woman starts walking south from a point 500 ft due east of P at 6 ft/s. To find the rate at which they are moving apart 15 minutes after the woman starts walking, we must consider the distance each has traveled in their respective directions by that time.

The man walks for a total of 20 minutes (15 minutes after the woman starts), while the woman walks for 15 minutes. The distance the man walks is 2 ft/s × 1200 s = 2400 ft and the woman walks 6 ft/s × 900 s = 5400 ft. Since they start 500 ft apart east to west, and move in north-south directions, the distance between them after 15 minutes can be found using the Pythagorean theorem: √(24002 + (500 + 5400)2) = √(5760000 + 32400000) = √38160000, which gives the distance between them. The rate of separation is the derivative of this distance with respect to time, assuming constant speeds.

Answer: decomposers

Explanation: they are microorganisms that are responsible for the decay and break down of dead organism into nutrients that are available for the plant

1. lifts it chest high

The force opposing to this action is the force due to gravity. Therefore the work done is:

W1 = m g d

where m is mass of the barbell, g is gravity and d is displacement

2. holds it for 30 seconds

Work is a product of force and displacement, since there is no displacement, therefore work done is zero.

W2 = 0

3. puts it down slowly

If the barbell was dropped, then it would simply be a free fall. But since it was not, so the work done here is also equal to the weight of the barbell times displacement:

W3 = m g d

We can see that W1 = W3, and since W2 = 0, therefore the answer is:

w3 = w1 > w2

Final answer:

In the context of a weight lifter lifting, holding, and lowering a barbell, work is done during the lifting (w1) and lowering (w3) phases due to the movement over a distance against a force. Holding the barbell stationary (w2) involves no work as there is no displacement. Thus, ranking in terms of work done would be w1 = w3 > w2, assuming equal force and displacement for lifting and lowering.

Explanation:

To answer the student's question effectively, we need to apply the concept of work from physics. Work is defined as the transfer of energy, and mathematically, it is the product of force and displacement in the direction of the force. Thus, work requires both force and movement in the direction of that force.

w1: Lifting the barbell chest high involves applying a force that moves the weights over a distance, hence work is done here.

w2: Holding the barbell in place does not involve movement. As there is no displacement, no work is done in the physics sense during this action. Therefore, w2 is zero.

w3: Lowering the barbell slowly back down also involves work since force is applied in controlling the movement against gravity over a distance.

Given the above understanding, w1 and w3 involve doing work, with w2 being zero due to no displacement. However, without specific values for force and displacement, it's challenging to directly compare the magnitude of work done between w1 and w3 precisely.

Conceptually, if the distance and force applied are the same for lifting and lowering, then w1 = w3 > w2. This scenario assumes identical distances and forces are applied in lifting up and lowering down the weights,

The most reactive element of this list is Chlorine, the next most reactive is bromine, and the least reactive is iodine.

All of these three elements are group 7 elements in the periodic table. It is known that the reactivity of group 7 elements decreases down the group. The most reactive element in this group is Flourine  with reactivity decreasing down the group.

The reason for this decrease in reactivity is that as you go down the group, the distance between the positive nucleus that attracts valence electrons increases, decreasing the electrostatic attraction between the nucleus and the outer electrons. The other reason is that the electrons in lower energy levels closer to the nucleus repel and shield the electrons in the outermost shell or energy level of the atom.

Chlorine>Bromine>Iodine.

Answer: The order of reactivity of non-metals from most reactive to least reactive is [tex]\text{Chlorine}>\text{Bromine}>\text{Iodine}[/tex]

Explanation:

Reactivity of a non-metal is defined as the tendency of an element to gain electrons. The reactivity increases as we move across a period and it  decreases as we move down the group.

When the size of an element increases, the valence electrons gets away from the nucleus and the tendency of an element to gain electrons decreases.

In a group, the size of an element increases because there is an addition of new shell and electron is added in that shell.

The given elements belong to the same group which is Group 17.

Chlorine has the smallest size, then bromine and then iodine.

Hence, the order of reactivity of non-metals from most reactive to least reactive is [tex]\text{Chlorine}>\text{Bromine}>\text{Iodine}[/tex]

Final answer:

Large bodies of water like oceans contribute to more moderate climates in coastal areas due to their thermal properties. Global warming is leading to sea level rise through glacial meltwater and thermal expansion, which affects coastal communities. Oceans also impact global weather patterns, including precipitation and climate, due to heat transport and storage.

Explanation:

Large bodies of water, like oceans and large lakes, have a significant impact on the climate of coastal communities. The thermal properties of water, which heats and cools more slowly than land, lead to moderate climates in coastal areas. These regions typically experience smaller temperature fluctuations both daily and seasonally, in comparison to interior landmasses. Additionally, global warming is causing sea levels to rise due to glacial meltwater and thermal expansion, further complicating the climate effects on coastal communities. The warmth of oceanic currents is transported across vast distances, affecting the weather patterns far inland as well.

As the planet warms, the rise in sea levels can lead to the inundation of shorelines, which poses challenges for coastal cities. This rising sea level can increase the impact of storm surges, putting infrastructure at risk. The warming of oceans also contributes to the continued melting of polar ice, which can disrupt the supply of freshwater and bring about long-term changes to global precipitation and climate patterns. Hence, the oceans play a crucial role in moderating global climate and the long-term implications of climate change.

Answer:

Acceleration is the rate of change in velocity.

Explanation:

Velocity,v-

"It is the change in a body's displacement or change in speed,d over the time,t."

Acceleration,a-

"When the body has a varying velocity,v across a given time frame,t is called as the acceleration,a."

Solution, colloids and suspension are distinctive sort of mixtures.

Air and dust are not solutions.

There is an uncertainty about whether air and dust form a colloid or a suspension.

Colloids don't partitioned, while suspension's segments do isolated. In the event that the residue is sufficiently little it will stay in air sufficiently long to be considered  a colloid for all efects.

At that point, the most satisfactory assessment is that the  blend of air and dust is a colloid.

So, option c. a colloid is the answer.

Colloid is a heterogeneous mixture in which molecule estimate is middle of genuine arrangement and suspension. Smoke from a fire is case of colloidal framework in which small particles of strong buoy in air. Some basic cases of colloids are jewel stones, smoke, cheddar, drain, cleanser foam and froth.

The pressure of the gas in this mercury manometer ( Figure 1 ) is about 864 mmHg

[tex]\texttt{ }[/tex]

The basic formula of pressure that needs to be recalled is:

Pressure = Force / Cross-sectional Area

or symbolized:

[tex]\large {\boxed {P = F \div A} }[/tex]

P = Pressure (Pa)

F = Force (N)

A = Cross-sectional Area (m²)

Let us now tackle the problem !

[tex]\texttt{ }[/tex]

In this problem , we will use Ideal Gas Law as follows:

Given:

height of mercury column = h = 89 mm

atmospheric pressure = Po = 775 mmHg

Asked:

the pressure of the gas = P = ?

Solution:

We will use Hydrostatic Pressure formula to solve this problem as follows:

[tex]P = Po + \rho g h[/tex]

[tex]P = 775 \texttt{ mmHg} + 89 \texttt{ mmHg}[/tex]

[tex]P = 864 \texttt{ mmHg}[/tex]

[tex]\texttt{ }[/tex]

The pressure of the gas in this mercury manometer ( Figure 1 ) is about 864 mmHg

[tex]\texttt{ }[/tex]

[tex]\texttt{ }[/tex]

Grade: High School

Subject: Physics

Chapter: Pressure

Answer:

Gamma rays

Explanation:

Trust me bro

The car's original speed can be calculated by utilizing the kinematic equation which is a principle in physics. Given that the car came to a stop with constant deceleration in a certain distance, the estimated initial speed was approximately 26.9 m/s.

The subject of the question involves concepts in physics specifically related to the equations of motion. To solve this, we can utilize the kinematic equation which relates initial velocity, acceleration, and distance: v2 = u2 + 2as, where 'v' is the final velocity, 'u' is the initial velocity, 'a' is acceleration and 's' is distance. Since the car comes to a stop, our final velocity v = 0 m/s. We know that the distance s = 30m and the acceleration is given as a = -3.50 m/s2 (negative because it's deceleration). From these, we can find the initial velocity 'u'. When we substitute these values into the equation, we can solve for 'u' as √(v2 - 2as), which equals approximately √(0 - 2*-3.50*30) ≈ 26.9 m/s. Therefore, the car's original speed was approximately 26.9 m/s.

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