A driver in a 2000 kg Porsche wishes to pass to pass a slow-moving school bus on a four-lane road. What is the average power in watts required to accelerate the sports car from 30 m/s to 60 m/s in 9 seconds

The work done by friction is -560 J

Explanation:

According to the work-energy theorem, the work done by the force of friction on the runner is equal to his change in kinetic energy. Therefore:

[tex]W=\frac{1}{2}mv^2-\frac{1}{2}mu^2[/tex]

where

W is the work done by friction

m is the mass of the runner

v is his final velocity

u is the initial velocity

Here we have:

m = 70 kg is the mass

u = 4 m/s is the initial velocity

v = 0 is the final velocity

Solving for W,

[tex]W=0-\frac{1}{2}(70)(4)^2=-560 J[/tex]

And the sign is negative because the direction of the force of friction is opposite to the motion of the runner.

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1) Distance: 14 km

2) Speed: 3.5 km/h

3) Displacement: 7.6 km at [tex]23.2^{\circ}[/tex] north of west

4) Velocity: 1.9 km/h at [tex]23.2^{\circ}[/tex] north of west

Explanation:

1)

Distance is a scalar quantity, and it corresponds to the total length of the path covered by an object during its motion, regardless of its direction.

Here we have the following motion:

[tex]d_{y1}=5 km[/tex] North

[tex]d_x = 7 km[/tex] west

[tex]d_{y2}=2 km[/tex] south

So, the distance covered is:

[tex]d=d_x + d_y = 5 + 7 +2 = 14 km[/tex]

And since it is a scalar, distance has no direction.

2)

Speed is a scalar quantity telling "how fast" an object is moving. It is calculated as:

[tex]speed=\frac{d}{t}[/tex]

where:

d is the distance

t is the time taken

In this problem, we have

d = 14 km (distance)

t = 4 h (time taken)

Substituting,

[tex]speed=\frac{14 km}{4 h}=3.5 km/h[/tex]

And since it is a scalar, it has no direction.

3)

Displacement is a vector quantity connecting the initial position to the final position of motion. The magnitude is the short distance in a straight line between the initial and final position of motion.

Here we have the following motions:

[tex]d_{y1}=5 km[/tex] North

[tex]d_x = 7 km[/tex] west

[tex]d_{y2}=2 km[/tex] south

So the net displacement in the north-south direction is

[tex]d_y = 5 - 2 = 3 km[/tex] North

[tex]d_x, d_y[/tex] are at right angle, so they form the sides of a right triangle, of which the hypothenuse corresponds to the displacement. Therefore, we can find the magnitude of the displacement by using Pythagorean's theorem:

[tex]d=\sqrt{d_x^2+d_y^2}=\sqrt{7^2+3^2}=7.6 km[/tex]

And the direction is given by

[tex]\theta=tan^{-1}(\frac{d_y}{d_x})=tan^{-1}(\frac{3}{7})=23.2^{\circ}[/tex] north of west.

4)

Velocity is a vector quantity, given by:

[tex]velocity=\frac{d}{t}[/tex]

where

d is the displacement

t is the time taken

In this problem, we have

d = 7.6 km (displacement)

t = 4 h (time taken)

So, the velocity is

[tex]velocity=\frac{7.6 km}{4h}=1.9 km/h[/tex]

And being a vector, velocity has also a direction, which is the same of the displacement: so, [tex]23.2^{\circ}[/tex] north of west.

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Answer:

The formula for potential energy is, P.E = mgh joules

The formula for kinetic energy is K.E = ½  mv² joules

Explanation:

                                      P.E = mgh joules

                                      K.E = ½  mv² joules

Answer:

955.36 seconds

Explanation:

Power is the rate of doing work over time

[tex]P=\frac{W}{t}[/tex]

We have

[tex]P=5.60* 10^7\ Watt[/tex]

[tex]W=5.35* 10^{10}\ Joule[/tex]

So the time taken is

[tex]t=\frac{W}{P}[/tex]

[tex]t=\frac{5.35* 10^{10}}{5.60*10^7} =955.36\ sec[/tex]

Answer:

The frequency of the wave is, f = 1 Hz

Explanation:

The half-wavelength of the wave can be found from the successive compression or rarefaction.

This is equal to the successive crest or trough.

The one wavelength is the wave that completes one cycle of vibration.

Therefore, the frequency of the wavelength is defined as the number of such vibrations per second. It is given by the formula

                                    f = 1 /T or v/λ   ( v - velocity of the wave)

                                      =  1 / 1

                                      = 1 Hz.

The unit of frequency is Hertz.

Answer:

Explanation:

In the above mentioned diagram it is shown that 2 compressions and 2 rarefactions are passing through a point in 1 second. Since a longitudinal wave is composed of 1 compression and 1 rarefaction therefore the frequency of the given wave is 2 Hz.

The man can survive, and he lands 12.1 m from the base of the cliff (into the lake)

Explanation:

The motion of the person is equivalent to the motion of a projectile, which consists of two separate motions:

- A uniform motion (constant velocity) along the horizontal direction

- An accelerated motion with constant acceleration (acceleration of gravity) in the vertical direction

We start by analyzing the vertical motion, to find the time it take for the person to reach the ground level. We can use the following suvat equation:

[tex]s=ut+\frac{1}{2}gt^2[/tex]

where

s = 50 m is the vertical distance covered (the height of the cliff)

u = 0 is the initial vertical velocity

[tex]g=9.8 m/s^2[/tex] is the acceleration of gravity

t is the time of flight

Solving for t,

[tex]t=\sqrt{\frac{2s}{g}}=\sqrt{\frac{2(50)}{9.8}}=3.19 s[/tex]

The person moved horizontally at a constant speed of

[tex]v_x = 3.8 m/s[/tex]

So, the horizontal distance covered by the man during his flight will be

[tex]d_x = v_x t = (3.8)(3.19)=12.1 m[/tex]

So, the man will land on the lake (which starts from 12 m), so he can survive.

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Answer:

Mathew, a farmer, cultivates monocultures of wheat. The negative effect that the monoculture farming have on Mathew’s land will be C. nutrients will not be recycled into the soil.

Explanation:

Monoculture farming is the practice of cultivating a single species of crop or plant at a time on farm. Growing the same crop again on the same land yearly destroys the nutrient of soil. It destroy the quality of soil and made farmers use more fertilizers.

The quality of the crop is degraded as it will not get the essential nutrients. But this practice is very popular as it increases the productivity of a particular species of crops. So by using this method, mathew will get these disadvantages.

Other options are incorrect as this practice will not cause water pollution. Neither it would produce greenhouse gases, nor it would decrease crop productivity.

Answer:

nutrients will not be recycled back into the soil

Explanation:

Plato :)

A chlorine atom can form an ionic bond by accepting an electron when reacting with sodium to form NaCl, and a covalent bond by sharing electrons when forming a [tex]Cl_2[/tex] molecule with another chlorine atom. This corresponds to option C.

The statement that best explains the behavior of chlorine in its reactions with sodium to form sodium chloride (NaCl) and with another chlorine atom to form chlorine molecule ([tex]Cl_2[/tex]) is: A chlorine atom can form ionic bonds by accepting an electron and covalent bonds by sharing electrons. This corresponds to option C.

When a chlorine atom reacts with a sodium atom, it forms an ionic bond by accepting an electron. The chlorine atom, which has seven electrons in its outer shell, gains one electron from the sodium atom, leading to the formation of a chloride ion ([tex]Cl^-[/tex]) with a net negative charge. The sodium atom loses an electron and becomes a sodium ion ([tex]Na^+[/tex]). These ions have opposite charges and are held together in a crystal lattice form of sodium chloride.

On the other hand, when a chlorine atom reacts with another chlorine atom, they share one electron each to complete their outer electron shells, forming a covalent bond to create the chlorine molecule, [tex]Cl_2[/tex].

the answer is b,c, and e

Answer:

BCE

Explanation:

Answer:

Nichrome has __High__melting piont​

Hope this helps

Answer:

high melting point

Nichrome is consistently silvery-grey in colour, is corrosion-resistant, and has a high melting point of about 1,400 °C (2,550 °F).

Explanation:

Answer:

0·2 m

Explanation:

The distance by which the axle of the wheel is rotated must be the same as the distance travelled by the plank, as it is mentioned that there is no slipping anywhere because if the distance is not same then there will be slipping between them as friction will be acting

Let the angle by which the wheel is rotated when it rolls by 1 m be β

∴ 1 = (outer radius of the wheel) ×β

1 = 0·25 × β

∴ β = 4 radians

The angle by which the wheel's axle is rotated will  be the same as the angle rotated by the wheel as both are attached

∴ Wheel's axle will also be rotated by an angle β = 4 radians

Distance by which the axle of the wheel will get rotated = (radius of wheel's axle) × β

 = 0·05 × 4 =0·2 m

∴ Plank will move from original position by 0·2 m

Answer:

Once you reach adulthood, you will not experience peer pressure.

Explanation:

We tend to believe that self-control comes from within, but many of our attitudes depend as much on friends and family as on ourselves. That's because at any stage of our life (even the adult stage) our friends and our family have the power to influence us, sometimes that influence is good and sometimes bad, it's up to us to reason about them.

The people around us have the power to make us fat, consume more alcohol, worry less about the environment and expose ourselves to the sun without proper protection, among many other things.

It is not simply about peer pressure, where you deliberately act in a certain way to suit the group. It is, in fact, largely an unconscious attitude. Without your awareness, your brain is constantly picking up cues from people around you to dictate your behavior. And the consequences can be serious.

Answer:

its B :)

Explanation:

Answer: Option C. Radio waves

Explanation:

Bluetooth technology primarily uses radio waves, a type of low-energy and invisible electromagnetic radiation, to enable wireless communication between devices.

Bluetooth is a technology that enables wireless devices to communicate with each other by transferring data and information. This is accomplished using low-energy radio waves. Among the wave types listed in your options, Bluetooth devices primarily use radio waves to establish communication. Radio waves are a form of electromagnetic radiation, similar to X-rays, red light and UV radiation, but are distinguished by their longer wavelength and lower frequency, which gives them their low energy characteristics. Because of their low energy, they are non-ionizing and safe to use. Also, radio waves are invisible to the human eye which meets the visibility requirement for Bluetooth technology.

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Answer:

The change in volume for a metallic dental filling due to the temperature difference is 0.1143 mm.

Explanation:

Given:

Temperature of the body is, [tex]T_1=37\ \°C[/tex]

Temperature of the ice-cream is, [tex]T_2=-6.2\ \°C[/tex]

Initial volume of the filling is, [tex]V=21.0\ mm^3[/tex]

Coefficient of thermal expansion is, [tex]\alpha =42.0\times 10^{-6}\ K^{-1}[/tex]

We know that the coefficient of volume expansion is related to thermal expansion as:

[tex]\gamma=3\alpha=3\times 42.0\times 10^{-6}=126\times 10^{-6}\ K^{-1}[/tex]

Now, change in volume for a metallic dental filling is given as:

[tex]\Delta V=V\gamma(T_1-T_2)\\\Delta V=21\times 126\times 10^{-6}(37-(-6.2))\\\Delta V=2646\times(37+6.2)\times 10^{-6}\\\Delta V=2646\times 43.2\times 10^{-6}\\\Delta V=0.1143\ mm^3[/tex]

Therefore, the change in volume for a metallic dental filling due to the temperature difference is 0.1143 mm.

The changes in volume for a metallic dental filling due to the difference between body temperature will be 0.1143 mm.

The expansion of any material due to the thermal application is known as thermal expansion.

The given data in the problem is;

Δv is the change in the volume =?

T₂ is the body temperature = 37.0°C

T₁  is the temperature of ice cream you ate (-6.2°C)

α is the expansion coefficient= 42.0 x 10⁻⁶ K⁻¹ mm

The coefficient of the volume expansion is given by;

[tex]\gamma = 3 \alpha \\\\ \gamma = 3 \times 42.0 \times 10^{-6} \\\\ \gamma = 126 \times 10^{-6}[/tex]

The change in the volume due to the thermal expansion is given by;

[tex]\triangle v = V \gamma (T_2-T_1) \\\\ \triangle v = 21 \times 126 \times 10^{-6} (37-(-6.2))\\\\ \triangle v = 2646 \times (37+6.2)\times 10^{-6} \\\\ \triangle v = 0.0143\ mm^3[/tex]

Hence the changes in volume for a metallic dental filling will be -18,62784 mm³.

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Answer:

18N & 360W

Explanation:

Here,

Velocity of car (v) = 72 ∗ 1000 / 60∗60 = 20m/s

weight of car = 1200N

We have,

μr = Fs / R

Fs = μr ∗ R = 0.015 ∗ 1200 = 18N

Power developed by the engine = 18 ∗ 20 =360W

Answer:

The current in the circuit will be [tex]5\times 10^{-3}\ Ampere[/tex].

Explanation:

Given:

Voltage difference = V = 5 V

Resistance              = R = 1000 ohms

To Find:

Current, I = ?

Solution:

Ohm's Law:

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

i.e  I ∝ V

∴ V = I × R

Where, I = current

           V = voltage

           R = resistance

Substituting the values of V and R we get

∴ 5 = I × 1000

[tex]I = \frac{5}{1000} \\I=0.005\ Ampere\\I=5\times 10^{-3}\ Ampere[/tex]

Therefore, the current in the circuit will be [tex]5\times 10^{-3}\ Ampere[/tex].

The current in the circuit can be found using Ohm's Law (I=V/R). The given values for voltage and resistance result in a current of 5 milliamperes.

The subject matter in the question falls under the field of Physics, particularly Electricity. The problem is asking for the current in a circuit, based on given values for voltage and resistance. One can solve this by employing Ohm's Law, which describes the relationship between voltage (V), resistance (R), and current (I). Ohm's Law is represented by the formula I = V/R.

Substituting the given values into the formula, the current I is calculated as 5V / 1000Ω, which equals 0.005 Amperes, or 5 Milliamperes (mA). Thus, the current flowing in the circuit is 5 mA.

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Answer: 51kg

Explanation:

Mass of the bicycle = 10 kg

Total force exerted = 176.9N

acceleration =  2.9 m/s2

Naoki's mass = ?

Total mass = mass of the bicycle + Naoki's mass

Recall : Force = mass x acceleration

Total force exerted = Total mass x acceleration

Let the Total mass be y , that is

176.9 = y x 2.9

176.9/2.9 = y

Therefore :

y = 61

Therefore , the total mass is 61kg , but the mass of the bicycle is 10kg , therefore , Naoki's mass = 61 - 10

= 51kg

The mass of Naoki is 51 kg.

Explanation:

According to second law of motions from Newton, external unbalanced force applied on an object will be equal to the product of mass and acceleration of the object.

As Naoki is sitting on a bicycle, the combined mass will be acting on the acceleration leading to the force of 176.9 N. So, the total mass of Naoki and bicycle can be determined from the mathematical representation of Newton’s second law of motion as below:

                [tex]\text {Force}=\text {Mass} \times \text {Acceleration}[/tex]

Thus,

               [tex]\text { Total Mass }=\frac{\text { Force }}{\text { Acceleration }}[/tex]

               [tex]\text { Total Mass }=\frac{176.9}{2.9}=61 \mathrm{kg}[/tex]

As the mass of the bicycle is given as 10 kg, so subtract the mass of the bicycle from the total mass to obtain the mass of Naoki.

Thus, mass of Naoki is

                    Total Mass-Mass of bicycle = Mass of Naoki

                     61-10 = 51 kg

So, the mass of Naoki is 51 kg.

14250. I just took it

Answer:

14,250 N

Explanation:

Weight = 14,700 N

Acceleration = -0.30m/s²

[tex]Acceleration = -0.30m/s2[tex]Weight=Fg\\\\Fg=mg\\\\Fg=14,700N\\m=?\\g=9.8m/s^{2} \\\\14,700N=m(9.8m/s^{2} ) \\\\14,700N/9.8ms^{2} =1500kg(mass)\\\\m=1500kg\\a=-0.30m/s^{2}\\\\f=ma\\f=(1500kg)(-0.30m/s^{2} )\\=-450N (net force)\\\\-450N=-14,700N+(Ft)\\14,250N=Ft[/tex]

2352 Joules is the “Gravitational potential energy” that a skater has.

Explanation:

"Gravitational potential energy" of an object is defined as the energy stored in the object which is at a height. Everybody at a height has some energy that is calculated by using the potential energy formula. Mathematically, "Gravitational potential energy" (GPE) is mass (m) times acceleration due to gravity (g) times height (h) of an object. Therefore, GPE = m × g × h.

From the given question,

Mass of the skater is 60 kg

The height at which skater is located is 4 m

“g” is acceleration due to gravity 9.8 [tex]m/s^2[/tex]

Substitute the given values in the GPE = m × g × h

Gravitational potential energy = 60 × 9.8 × 4

Gravitational potential energy = 2352 J .

Answer:

Mass and height

Explanation:

Gravitational potential energy is energy an object possesses because of its position in a gravitational field. The most common use of gravitational potential energy is for an object near the surface of the Earth where the gravitational acceleration can be assumed to be constant at about [tex]9.8 m/s2.[/tex]

Which is represented as;

[tex]PE_g=mgh[/tex]

[tex]PE_g[/tex] stands for gravitational potantial energy,

m stands for mass of object,

g is the gravitational constant and

h is the height.

Here we see that mass of object and height is directly proportional to the gravitational potential energy.

That means increasing in mass and height will result in increasing gravitational potential energy.

Answer:  

X: radius  

Y: tangential speed  

Explanation:  

Just took the test and got it right

In the table for centripetal acceleration equations, X refers to the radius of the circular path, and Y denotes the tangential speed of the object in circular motion.

The quantities that belong in cells X and Y in the student's table for the equations for centripetal acceleration are as follows:

In the context of circular motion, the variable r represents the radius of the circular path, and the variable v is the tangential speed or linear speed along the circular path. The variable ac stands for centripetal acceleration, which points toward the center of the circular path and is dependent on both r and v. The variable T represents the period, which is the time it takes to complete one full circle along the path.

Answer:

The correct answer is option A).

Explanation:

The given reaction is a nuclear reaction.

We know that in a nuclear reaction , the indices on both the sides are conserved , i.e the  total number of nucleons (A) and the total number of protons (Z) should be the same on the L.H.S and the R.H.S-

Total number of nucleons on L.H.S = 241+4 = 245.

Total number of nucleons on R.H.S =  A+1

∴ A+1 = 241+4 = 245

∴ A=244

Total number of protons on L.H.S = 95+2 = 97.

Total number of protons on R.H.S = Z+0

∴ Z+0 = 97.

Z = 97.

Thus the element having A=244 and Z=97 should be the  product of this nuclear reaction.

∴   ₉₇²⁴⁴Bk (option A) should be the required product of this reaction.

Answer: 0 newtons

Explanation: If you push a cart to the right with 5 newtons of force to the right and a friend pushes the cart 5 newtons to the left, there will be no motion.

To understand this further, take a look at the image I provided. I provided two arrows one of the left and on on the right. If two people are pushing on the cart with the same amount of force, the net force will be 0 so it will be a balanced force. When we have a balanced force, there's no motion.

Answer:

Reference Point

Explanation:

Answer: Line graph

Explanation:

Allison needs to graph the yearly average snowfall in Alaska. She should use a:

pie chart

pictograph

bar graph

line graph

Answer:

Option a

Explanation:

The action of the rapid rubbing of the hands are a result of chemical reaction and responses that takes place inside our body.

When we rub our hands together, that shows the mechanical motion of the body or we can say that while rubbing hands chemical energy gets converted to mechanical energy (here, Kinetic energy).

While rubbing, due to friction, heat is produced and hence we can say that this mechanical energy has transformed to heat energy.

Thus the conversion here is from chemical to mechanical to heat energy.

Answer:

The answer is option B, horn.

Explanation:

The landform horn was formed because when glaciers erode down to form a sharp peak which is called a horn. All of the other options are false because none of those land forms are formed because of the erosion of glaciers

Answer:

i think a delta

Explanation:

I might be wrong but I think it leaves behind a delta.

Answer:

90km

Explanation:

every hour you travel 30km and you are traveling 3 hours 30×3

The coefficient of friction is 0.363

Explanation:

There are two forces acting on the scooter in the horizontal direction:

- The applied force, F = 1850 N, forward

- The frictional force, [tex]F_f[/tex], backward

Since the scooter is moving at constant speed, the acceleration is zero, so the net force acting on the scooter must be zero. Therefore we can write:

[tex]F-F_f = 0\\F_f = F = 1850 N[/tex]

The frictional force can be written as

[tex]F_f = \mu R[/tex] (1)

where

[tex]\mu[/tex] is the coefficient of friction

R is the normal reaction of the ground on the scooter

For a flat horizontal surface, there is equilibrium along the vertical direction, so the normal reaction is equal to the weight:

[tex]R = W = mg[/tex]

where

m = 520 kg is the mass

[tex]g=9.8 m/s^2[/tex] is the acceleration of gravity

Substituting into (1),

[tex]F_f = \mu mg = 1850 N[/tex]

and solving for [tex]\mu[/tex],

[tex]\mu=\frac{F_f}{mg}=\frac{1850}{(520)(9.8)}=0.363[/tex]

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