Which of the following shows a car that is increasing in speed

Answer:

The minimum force the climber must exert is about 439N.

Explanation:

We use the relationship between friction and normal force to answer this question:

[tex]F_{friction} = \mu_{static} \cdot F_{normal}\implies F_{normal}=\frac{F_{friction}}{\mu_{static}}[/tex]

We are given the static coefficients of friction but need to determine the friction force. To do that we consider the totality of forces acting on this hapless gentleman stuck in a chimney. There is the gravity acting downward (+), then there are two friction forces acting upward (-), namely through his shoes and his back. The horizontal force exerted by the climber on both walls of the chimney is the same and is met with equally opposing normal force. Since the climber is not falling the net force in the vertical direction is zero:

[tex]F_{net} = 0 = F_g - F_{shoes}-F_{back}= mg - \mu_{shoes}F_{norm}-\mu_{back}F_{norm}\\F_{norm}=\frac{mg}{\mu_{shoes}+\mu_{back}}=\frac{64.5kg\cdot 9.8\frac{m}{s^2}}{0.8+0.64}\approx 438.96N\\[/tex]

The normal force in this equilibrium is about 439N and  because we are told that the static friction forces are both at their maximum, this value is at the same time the minimum force needed for the climber to avoid starting slipping down the chimney.

The climber must exert normal forces with his shoes and back to stay stationary in the chimney, counteracting his weight through friction. Assuming an even distribution for simplicity, a normal force of at least 439.24 N at each point would be necessary to maintain his position.

Minimum Normal Force by a Climber

To determine the minimum normal force the climber must exert to stay stationary in the chimney, we first need to consider the forces acting on the climber. There are two frictional forces that counteract the climber's weight: the friction on the shoes and the friction on the back. Since we are ignoring the climber's grip on the rope, these frictional forces are the only forces preventing the climber from falling.

The climber's weight (W) is calculated by the formula W = m × g, where 'm' is the mass of the climber (64.5 kg) and 'g' is the acceleration due to gravity (9.8 [tex]m/s^2[/tex]). For the climber to remain stationary, the friction forces (f) on both the shoes and the back must equal the weight. The maximum friction force is given by f = μ × N, where 'μ' is the coefficient of friction and 'N' is the normal force.

The total normal force exerted by the climber is the sum of the normal forces from the shoes and the back. To find the minimum normal force, we set the two friction forces equal to the climber's weight:

[tex]f_{shoes} = \mu_{shoes} \times N_{shoes}\\f_{back} = \mu_{back} \times N_{back}\\W = f_{shoes} + f_{back}[/tex]

Solving for [tex]N_{shoes}[/tex] and [tex]N_{back}[/tex] gives us the total normal force required, which must be the sum of the two since they happen at different points on the climber's body.

The static coefficients of friction given are 0.80 for the shoes and 0.64 for the back. We can use these to find the normal force exerted at each point if we knew the distribution of weight between the climber's shoes and back, which isn't provided. If we assume an even distribution for simplicity, though it's not necessarily accurate, the calculation would be as follows:

W = 64.5 kg × 9.8 [tex]m/s^2[/tex] = 632.1 N

[tex]F_{shoes} + F_{back} = W\\0.80 \times N_{shoes} + 0.64 \times N_{back} = 632.1 N[/tex]

If [tex]N_{shoes}[/tex] = [tex]N_{back}[/tex] (even distribution), then [tex]N_{shoes}[/tex] = [tex]N_{back}[/tex] = 632.1 N / (0.80 + 0.64)

[tex]N_{shoes}[/tex] = [tex]N_{back}[/tex] = 632.1 N / 1.44

[tex]N_{shoes}[/tex] = [tex]N_{back}[/tex] = 439.24 N

Therefore, the climber must exert a normal force of at least 439.24 N with each his shoes and back in an ideal even distribution scenario to not fall.

Answer:

1. A graph is defined as " A Diagram represents a system of connections or interrelations among two or more things by a number of different dots, lines etc".

2. In simple words "Graph is a representation of any object or a physical structure by dots, lines, etc.

Answer:

The pressure on the ground is about 9779.5 Pascal.

The pressure can be reduced by distributing the weight over a larger area using, for example, a thin plate with an area larger than the circular area of the barrel's bottom side.  See more details further below.

Explanation:

Start with the formula for pressure

(pressure P) = (Force F) / (Area A)

In order to determine the pressure the barrel exerts on the floor area, we need the calculate the its weight first

[tex]F_g = m \cdot g[/tex]

where m is the mass of the barrel and g the gravitational acceleration. We can estimate this mass using the volume of a cylinder with radius 30 cm and height 1m, the density of the water, and the assumption that the container mass is negligible:

[tex]V = h\pi r^2=1m \cdot \pi\cdot 0.3^2 m^2\approx 0.283m^3[/tex]

The density of water is 997 kg/m^3, so the mass of the barrel is:

[tex]m = V\cdot \rho = 0.283 m^3 \cdot 997 \frac{kg}{m^3}= 282.151kg[/tex]

and so the weight is

[tex]F_g = 282.151kg\cdot 9.8\frac{m}{s^2}=2765.08N[/tex]

and so the pressure is

[tex]P = \frac{F}{A} = \frac{F}{\pi r^2}= \frac{2765.08N}{\pi \cdot 0.3^2 m^2}\approx 9779.5 Pa[/tex]

This answers the first part of the question.

The second part of the question asks for ways to reduce the above pressure without changing the amount of water. Since the pressure is directly proportional to the weight (determined by the water) and indirectly proportional to the area, changing the area offers itself here. Specifically, we could insert a thin plate (of negligible additional weight) to spread the weight of the barrel over a larger area. Alternatively, the barrel could be reshaped (if this is allowed) into one with a larger diameter (and smaller height), which would achieve a reduction of the pressure.  

Answer: 9 m

Explanation:

Work is said to be done when an unbalanced force causes displacement of the body.

Force is the product of mass (m) and acceleration (a).

Work = Force × Displacement

⇒W = F.s = ma.s

It is given that mass of the dresser is, m = 250 kg

work done, W = 126 J

Force acting on the dresser, F = 14 N

we need to find displacement, s

⇒126 J = 14 N × s

⇒ s = 126 J/ 14 N = 9 m

Hence, Laurie is able to move the dresser to about 9 m.

Answer:

9 m

Explanation:

When an object moves or displaces along the direction of the applied force application of force, it is said that work is done.

We know the formula of work:

Work = force x displacement

where force = mass x acceleration

So this formula can be further broken down to :

Work = mass x acceleration x d

Putting in the given values to get:

126 = 14 x d

d = 126/14

d = 9 m

Therefore, the dresser was moved by 9m.

A: holding open a door

Answer:

1385 N/m^2

Explanation:

The pressure exerted by the brick on the ground is given by:

[tex]p=\frac{F}{A}[/tex]

where F is the weight of the brick and A is the area of its largest face.

The area of the largest face is given by the two largest sides of the brick, therefore:

[tex]A=(0.19 m)(0.095 m)=0.01805 m^2[/tex]

The force exerted by the brick is the weight:

[tex]F=25 N[/tex]

So, the pressure is

[tex]p=\frac{25 N}{0.01805 m^2}=1385 N/m^2[/tex]

The pressure exerted by the brick when resting on its largest face is calculated by dividing the weight of the brick (25 N) by the area of the largest face (0.01805 [tex]m^2[/tex]), resulting in a pressure of 1385 [tex]N/m^2[/tex].

The question seeks to calculate the pressure exerted by a brick on the ground when it is resting on its largest face. To find the pressure, we use the formula Pressure (P) = Force (F) / Area (A). Here, the force is the weight of the brick, which is given as 25 N.

Since pressure is force per unit area, we need to identify the area of the largest face of the brick. The dimensions of the brick are 0.19 m, 0.07 m, and 0.095 m. The largest face would be the one formed by the sides measuring 0.19 m and 0.095 m. Thus, the area is A = 0.19 m × 0.095 m = 0.01805 [tex]m^2[/tex].

To calculate the pressure, we divide the force (weight) by the area:

P = F / A = 25 N / 0.01805 m2 = 1385 [tex]N/m^2[/tex]

Therefore, the pressure exerted on the ground by the brick resting on its largest face is 1385 [tex]N/m^2[/tex].

That is a Wave Length.

Properties that define the light is a wave are

1. Speed : speed of light is 300,000 Km /s, It is most fundamenta property of light to define light is a wave

2. Reflection: Light particles or photons reflect off the particles or masses are continue to travel at the same speed.

3. colour

Answer:

Properties that define the light is a wave are

1. Speed : speed of light is 300,000 Km /s, It is most fundamental property of light to define light is a wave

2. Reflection: Light particles or photons reflect off the particles or masses are continue to travel at the same speed.

3. color

Explanation:

1. protons 2. neutrons

Answer:

protons

neutrons

Explanation:

Causes of a severe storm are:

High winds

wildfires

hail

A severe thunderstorm includes winds of 58 MPH or greater

Answer:

The object exerts same amount of force in elastic and inelastic collisions.

Explanation:

The force an object exerts is not different between the two types of collisions. What changes from elastic to inelastic is the amount of energy transformed from kinetic to other type during an inelastic collision.

Answer: A ( 0)

      When the force is balanced then the object is accelerating and in the state that will be called "equilibrium".

       When the object is in equilibrium "Net force is zero"

                          Fnet = 0

Answer:

the correct answer is A

Explanation:

because i have this question a usatestprep and i choose C i got it wrong and the answer was A

Your most likely answer would be D, though, I'm not too sure on it.

However, conduction is present during this process, as well for convection. Convection started up the heating process, and it caused conduction within the pan.

I'm hoping this helps you out.

Answer:

Convection in Step 1 and conduction in Steps 2 and 3

Explanation:

Convection is the fire and the clue word that led me to conduction for steps 2/3 is "touches" it was either Radiation in Step 1 and conduction in Steps 2 and 3 OR Convection in Step 1 and conduction in Steps 2 and 3 and it is not radiation because there is no electromagnetic waves in the flame so its Convection in Step 1 and conduction in Steps 2 and 3, THE LAST ONE, D

Chemical to Electrical

its electrical because it runs on a battery

Answer:

C. Blue stars

c

Explanation:

For stars in the main sequence, the absolute brightness tends to increase with decreasing surface temperature. Therefore, blue stars, which are hotter, tend to have higher absolute brightness compared to red stars, which are cooler. So, the correct answer is:

C. Blue stars

A star with an absolute brightness of -3 and a surface temperature around 20,000°C would likely be a main sequence star. Main sequence stars are characterized by their stable fusion of hydrogen into helium in their cores, and they cover a wide range of temperatures and absolute brightnesses. The combination of a relatively high absolute brightness and a high surface temperature suggests that this star is likely in the main sequence phase of its life cycle.

C. Blue stars

Non-foliated metamorphic rocks are rocks that have been changed by heat and pressure into rocks with a non-layered or banded appearance. Some examples of non-foliated metamorphic rocks include quartzite, marble, amphibolite and hornfels.

Non-foliated metamorphic rocks are rocks that have been changed by heat and pressure into rocks with a non-layered or banded appearance. Some examples of non-foliated metamorphic rocks include quartzite, marble, amphibolite and hornfels.

Let say the ball is projected in air with speed "v" at an angle of 45 degree

now the two components of its velocity will be given as

[tex]v_x = vcos45 = 0.707 v[/tex]

[tex]v_y = vsin45 = 0.707 v[/tex]

now the maximum height reached by the ball is 49 m

so as it will reach to maximum height its velocity in y direction will become zero

so we can use kinematics in y direction

[tex]v_f^2 - v_i^2 = 2 a y[/tex]

[tex]0 - (0.707v)^2 = 2(-9.8)(49)[/tex]

[tex]0.5v^2 = 960.4[/tex]

[tex]v = 43.8 m/s[/tex]

so the speed with which ball is projected upwards must be 43.8 m/s

A negative to a negative charge will make a neutral charge.

Answer:

Any combination of positive and negative charges that are in balance, as well as additional neutral charges.

Explanation:

A particle will have a neutral charge if and only if its components (subparticles) comprise an equal number of positive and negative charges, plus any number of neutral charges.

Answer:

The energy depends on the object's mass, height above Earth's surface, and the gravitational acceleration constant.

Explanation:

The potential energy is a relationship as follows:

[tex]E_p = m\cdot g\cdot h[/tex]

where m is the mass of the object (kg), h is the height/altitude of the aboject measured in meters above Earth's surface, and g is the gravitational acceleration, typically take to be 9.8 m/s^2.

Gravitational potential energy is dependent on the object's mass, its height above a reference point, and the gravitational acceleration, encapsulated by the formula ΔPEg = mgh. This energy is associated with the state of separation between the object and the Earth. The difference in gravitational potential energy carries physical significance.

The gravitational potential energy that an object possesses is dependent on multiple factors. Key among these is the mass of the object, the height above the reference point (usually Earth's surface), and the gravitational acceleration (which is approximately 9.8 m/s² near the surface of the Earth). These variables relate based on the equation ΔPEg = mgh, where ΔPEg represents the change in gravitational potential energy, m is the mass, g is the gravitational acceleration, and h is the height increase.

For instance, when we lift an object, work is done against gravity and it becomes potential energy of the object-Earth system. This energy is associated with the state of separation between two objects that attract each other by the gravitational force. Notably, it is the difference in gravitational potential energy that holds physical significance.

To illustrate, consider a roller coaster car at the top of a hill. It has gravitational potential energy due to its elevated position above Earth's surface. As it descends, this stored energy is converted into kinetic energy, or energy of motion, propelling the car downwards.

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Answer:

C.The car appears to be moving 30 km/hr in the opposite direction of the bus.

Explanation:

There are two reference systems involved in this situation:

- Reference system S: this is the reference system where velocities are measured with respect to the ground. In this reference system, the car is parked, so its velocity is [tex]v=0[/tex]

- Reference system S': this is the reference system moving with the bus. This reference system is moving with a velocity of [tex]v_0 = +30 km/h[/tex] with respect to the reference system S

Calling [tex]v'[/tex] the velocity of the car in the reference system S', we have:

[tex]v=v_0 +v'[/tex]

From which

[tex]v'=v-v_0 = 0-(+30 km/h)=-30 km/h[/tex]

and the negative sign means that a passanger in the bus observes the car moving in the opposite direction.

Because the paint over the iron of the car helps to keep the iron from coming in contact with air, and that's why cars in junkyards are usually rusted, because the paint is chipped or gone.

Iron rusts because it can be contacted by water-or the moisture in the air- and the metal takes the oxygen from the water forming iron oxide-rust. Paint or plating (like chrome plating) prevents the H2O molecules from reaching the surface of the metal so it can't get the oxygen.

The unit of magnetic flux is 1 Weber (Wb).

The different types of radiation are defined by the the amount of energy found in the photons. Radio waves have photons with low energies, microwave photons have a little more energy than radio waves, infrared photons have still more, then visible, ultraviolet, X-rays, and, the most energetic of all, gamma-rays

hope this helps change it up a little

The energy of these spectral bands are related through the Einstein-Planck formula:

E = h * f

with h the Planck's constant and f the frequency of the electromagnetic wave.

Since the (frequency of infrared) is < (frequency of visible) < (frequency of ultraviolet), from the Einstein-Planck relationship it follows that the (energy of infrared) < (energy of visible) < (energy of ultraviolet).

The gravitational force an object exerts is influenced by its mass and distance. From the options, the moon exerts the most gravitational force because of its significant mass, despite being far away.

The factor that determines the gravitational force exerted by an object is both its mass and the distance from it. The equation for gravitational force is F = G * (m1 * m2) / r^2, where 'G' is the gravitational constant, 'm1' and 'm2' are the masses of the two objects, and 'r' is the distance between their centers.

In the options given: the remote control, the couch, TV actors, and the moon, despite the latter being far off, still, the moon exerts the strongest gravitational force on you. The magnitude of gravitational force exerted by the moon is larger due to its massive size compared to the rest, even though it's far away. The effect is noticeable in the ebb and flow of ocean tides caused by the moon's gravity.

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It could prevent the key from sinking because the wood would float.

It floats because it weighs less than amount of water it would have to push out of the glass if it sank. Wood, cork, and ice are all less dense than water, and they float; rocks are more dense, so they sink. A key would also be more dense causing it to sink.

Hope this helps,

Davinia.

Attaching the key to a piece of wood could prevent the key from sinking

because the weight of a piece of wood is light when compared to that of the

key.

The wood will however float because the weight of the wood is less than the amount of water that will be displaced.

On the other hand, the key will sink as a result of the weight of the key being

more than the amount of water that will be displaced. Attaching the key to the wood will thereby prevent it from sinking

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An object moving in a circle is accelerating. Accelerating objects are objects which are changing their velocity - either the speedor the direction. An object undergoing uniform circular motion is moving with a constant speed.

Uniform circular motion occurs when an object moves along a circular path at a constant speed, involving constant centripetal acceleration due to the continuous change in direction, despite the speed being unchanged.

What circular motion occurs when an object is traveling with constant speed in a circle? The answer is uniform circular motion. This phenomenon occurs when an object moves along a circular path with a constant speed. Despite the speed being constant, the direction of the motion changes continuously, leading to a change in velocity. Since velocity is a vector quantity that depends on both speed and direction, its alteration signifies the object is accelerating. This type of acceleration is known as centripetal acceleration, which is always directed towards the center of the circle.

Three critical constants in uniform circular motion include the radius of the circular path, the magnitude of acceleration, and the speed of the object. These constants ensure the motion is uniform, meaning the object covers equal distances along the circle in equal intervals of time. While the speed remains unvaried, the acceleration involved is necessitated by the need to continuously change the direction of the velocity vector.

In summary, uniform circular motion is characterized by constant speed but changing velocity due to continual directional changes. The consistent change in direction necessitates centripetal acceleration, making the motion unique in its dynamics and effects, such as those felt on a roller coaster during rapid turns. Understanding this concept is fundamental in explaining various phenomena in physics and related fields.

Answer:North-South

Explanation:

The freely suspended bar magnet will always lie in a north-south direction. Therefore, the swinging bar magnet will come to rest in north -south direction.

A bar magnet is a rectangular piece of object which exhibits permanent magnetic properties.  A bar magnet is made of iron, steel or other ferromagnetic substances.

A bar magnet have two poles, a north pole and a south pole. The two opposite poles of two magnets will attracts each other whereas, two like poles will repel each other.

The south pole of a bar magnet is aligned towards the geographic north pole. When a bar magnet is suspended freely, the magnet will aligns itself so that the north pole is pointing to the geographic north pole. Thus  option d is correct.

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If it produces 20J of light energy in a second, then that 20J is the 10% of the supply that becomes useful output.

20 J/s = 10% of Supply

20 J/s = (0.1) x (Supply)

Divide each side by 0.1:

Supply = (20 J/s) / (0.1)

Supply = 200 J/s  (200 watts)

========================

Here's something to think about:  What could you do to make the lamp more efficient ?  Answer:  Use it for a heater !

If you use it for a heater, then the HEAT is the 'useful' part, and the light is the part that you really don't care about.  Suddenly ... bada-boom ... the lamp is 90% efficient !

The lamp is 10% efficient which means it converts only 10 % of its input energy into output. Hence, it will produce  20 J/s when an energy of 200 J/s is applied.

Electrical energy is a form of energy generated by the movement of free electrons from the valence band to the conduction band. Electrical energy can be converted to other forms of energy such as light energy, mechanical energy etc.

The efficiency of an electric device is its ratio of the input energy to the output energy. No device can be 100 % efficient because the a significant portion of the applied energy is lost in the form of heat energy.

Given that the efficiency of the lamp is 10%. Thus, it converts only 10 % of its input energy to the output. The output energy is 20 J/s. Which is 10% of 200J/s. Therefore, the energy applied here is 200 J/s.

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That is might thick wire. I'm not sure I've seen anything with 1/5 inch diameter.

The answer is A.

That is the exact diameter attributed to AWG 4 wire.