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The info below shows a kettle with its powers and the time they take to boil 500cm3 of water. If electricity costs 9p per unit, how much does it cost to boil 500cm3 of water using the 1.4kW kettle?

Kettle1= 1.4kW =4.5minutes

Answer:

An open system.

Explanation:

An isolated system allows the exchange of neither energy nor matter with the surroundings. A closed system allows the exchange of energy, but not matter. An open system allows the exchange of both energy and matter.

Notice that in this question, light (electromagnetic wave) is a form of energy. The entry and exit of light allows this system to exchange energy with its surroundings- just as how the earth receives energy from the sun. Additionally, this system could exchange energy with its surroundings through the exchange of matter (in particular, air) with its surroundings.

Thus, the system in this question is an open system.

Answer:

você tem um camping de em Rio do Rio de Janeiro ou em lojas em SP e SP e RJ e região metropolitana de Porto Velho de Porto Velho Rio

Long distance running is the physical activity I engage in now, and there are a number of items and programs that can greatly improve my performance.

A GPS powered watch is one such item which I think is quite useful. I can monitor my speed, distance, heart rate and other important information while running with this device. This data lets me change my pace, track my effort, and make sure I stay within my desired heart rate range. The watch also provides post-run analysis, which I can use to identify my weaknesses and modify my training appropriately. In my opinion, GPS running watches have changed the game by allowing me to run harder and push my physical limits.

A strength training program designed for runners has also been very helpful in enhancing my performance. The program's primary emphasis is on functional workouts that target the major running muscle groups, such as the core, glutes and legs.

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The constant G in Newton's equation makes the units of measurement consistent was measured by Newton shows gravity to be a relatively huge force produces equilibrium makes the units of measurement consistent.

The three fundamental laws of classical mechanics known as Newton's laws of motion describe how an object's motion and the forces acting on it interact.

Newton's first law, an object will not change its motion unless a force acts on it.

Newton's second law, the force on an object is equal to its mass times its acceleration.

Newton's third law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction.

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The time needed for the hammer to reach the surface of the Earth is 3.54 s.

The time of motion is calculated as follows;

t = √(2h/g)

where;

t = √(2 x 10 / 1.6)

t = 3.54 s

Thus, the time needed for the hammer to reach the surface of the Earth is 3.54 s.

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The speed of the boat is 4 m/s.

The system for pace is speed = distance ÷ time.

To work out what the devices are for pace, you want to understand the gadgets for distance and time. In this case, distance is in meters (m) and time is in seconds (s), so the gadgets could be in meters according to second (m/s).

To resolve for speed or price use the components for pace, s = d/t which means that pace equals distance divided through time.

The pace is a manner of measuring how quickly something is transferring or being performed, or something moving speedily. An example of speed is a vehicle being driven 45 miles in keeping with the hour. An instance of velocity is a person cleaning a room in 10 minutes. An example of velocity is how quickly a jaguar runs.

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Answer:

The hair dryer will transfer 640J of energy usefully to Nora’s hair.

Explanation:

Efficiency = output/input × 100%

Data

Efficiency = 64%

Energy input = 1000J

Energy output = ?

Efficiency = Energy output/Energy input × 100%

64% = Energy output /1000J × 100%

Divide both sides by 100%

0.64 = Energy output/1000J

Energy output = 0.64 × 1000J

Efficiency output = 640J

Therefore the hair dryer will transfer 640J of energy usefully to Nora’s hair.

The time taken by the pulse to travel from one support to the other is 0.208 s.

The mass of the cord is m = 0.65 kg.

The distance between the supports is, d = 8.0 m.

The tension in the cord is T = 120 N.

The time taken by the pulse to travel from one support to the other is given as,

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

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

Here, v is the linear velocity of a pulse. Its value is,

[tex]v=\sqrt{\frac{T d }{m} }[/tex]

[tex]v=\sqrt{\frac{120 * 8}{0.65} }[/tex]

[tex]v= 38.43 m/s[/tex]

Then,

[tex]t=\frac{8}{38.43}[/tex]

[tex]t=0.208 s[/tex]

Thus, the time taken by the pulse to travel from one support to the other is 0.208 s.

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D.  The movement that will require the greatest amount of work to be

done is a force of 15n moving an object a distance of 5.0m (75 J).

Work is said to be done when an applied force moves an object over a given distance.

W = Fd

where;

W = 10 x 3 = 30 J

W = 10 x 5 = 50 J

W = 15 x 3 = 45 J

W = 15 x 5 = 75 J

Thus, the movement that will require the greatest amount of work to be

done is a force of 15n moving an object a distance of 5.0m (75 J).

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The normal force is 2820.48N in the negative y direction.

Force = mass × acceleration

F = m×A

Note that rocket takes off from Earth's surface, accelerating straight up at 31.2 m/s² .

The rocket accelerates upwards, hence the acceleration will be negative because it defies gravity's law (it keeps going into space without coming down)

Acceleration of the rocket = -31.2m/s²

Mass of the astronaut = 90.4kg

Normal force acting on the astronaut = -31.2 × 90.4kg

                                                                 = -2820.48N

Therefore, the normal force is 2820.48N in the negative y direction.

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The net force (magnitude and direction) of the system given in the question is 40 N horizontal to the right

Case 1 (Net force between up and downward force)

F1 = Fu - Fd

F1 = 50 - 30

F1 = 20 N up

Case 2 (Net force between right and left)

F2 = Fr - Fl

F2 = 60 - 20

F2 = 40 N right

SUMMARY

From the above, the net force between right and left (i.e 40 N) is greater than the net force between up and down (i.e 20 N)

Thus, the net force of the system will be 40 N horizontal to the right

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Answer:

1.8 = relative density (there are no units for relative density)

Explanation:

It displaces water equal to it's volume and gets buoyancy equal to that amount of water

2.7 - 1.2  = 1.5  N  of buoyancy

density of water = 1 gm /cc

 1.5 N = m (9.81)

    m of water displaced = .1529 kg

             152.9 cc of water will produce this buoyancy....this is the volume of the object

find mass of object     2.7 = m (9.81)     shows m = .2752 kg = 272.5 gm

density = mass/ volume = 272.5 / 152.9 = 1.8 gm / cc

Relative to water (which is 1 gm / cc) the relative density is 1.8

  ====> it is 1.8 times denser than water and will sink when in water....

The charge on each of the equally charged drops of hairspray willl be 7 × 10 ⁻¹³ C

The force of attraction between two charges, according to Coulomb's law, is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

Similar charges repel each other, whereas charges that are opposed attract each other.

Given data;

Electric force,F = 9 × 10 ⁻⁹ N

Distance between charges,d = 7 × 10⁻⁴ m

Chrge,q₁ = q₂ =q C

From Columb's law;

[tex]\rm F = K \frac{q_1q_2}{d^2} \\\\ 9 \times 10^{-9} = 9 \times 10^9 \frac{q^2}{(7 \times 10^{-4})^2} \\\\ q^2 = 4.9 \times 10^{-25} \\\\ q = 7 \times 10^{-13} \ C[/tex]

Hence the charge on each of the equally charged drops of hairspray willl be 7 × 10 ⁻¹³ C

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Answer: Two children are riding on a marry-go-round. Child A is at a greater distance from the axis of rotation than child B. Thus, the child A, located at a greater distance from the axis of rotation have a larger tangential speed.

Explanation: To find the correct answer we have to know more about the Angular velocity of a rotating body.

                              [tex]w=V/r[/tex]

                               [tex]V=wr[/tex]

Thus, we can conclude that, child A with greater distance will have larger tangential speed.

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The car will skid at 80m

As we know that In mechanics, acceleration is the rate of change of the velocity of an object with respect to time.

It is a vector quantity

The velocity is the distance covered by an object per unit time

Given

Initial velocity (u) = 15m/s

Final Velocity (v) = 0m/s

Distance (s) = 20 m

Deceleration (a) =?

Now we know that ,

v² = u² + 2as

Substituting the value

0² = 15² + (2)*(a)*(20)

0 = 225 + 40a

Collecting the  like terms

0 – 235 = 40a

–225 = 40a

To find the value of a divide  both side 40

a = –225 / 50

a = –5.625 m/s²

Determination of the distance

Deceleration (a) = –5.625 m/s²

Initial velocity (u) = 30 m/s

Final velocity (v) = 0 m/s

Distance (s) =?

v² = u² + 2as

0² = 30² +(2 × –5.625 × s)

0 = 900 – 11.25s

Collecting  like terms

0 – 900 = –11.25s

–900 = –11.25s

To find the value of s divide both side by –11.25

s = –900 / –11.25

s = 80 m

Hence the car will skid 80 m

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The time required to accelerate this car from rest to a speed of 100 km/h at full power on a level road is 7.73 seconds.

Mass of the engine = 1500 kg

Power rating = 75 kW = 75,000 W

Final speed = 100 km/hr =  = 27.78 m/s

v₁ = 0

Power = Work done ÷ Time

Work done = Final energy - Initial energy

=1/2 x 1560 x 27.78^2 = 1/2 x 1560 x 0^2\

= 578703.72 J

Thus,

75,000 = 578703.70 ÷ time=7.72 seconds.

Work is done every time a force moves something over a distance. By multiplying the force by the distance traveled in the direction of the force, you can calculate the energy transferred or the work done. Energy transmitted = work completed = force x distance traveled in the direction of the force.

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Step 1 of 6

Diameter of the blimp,

Length of the blimp,

Rope tension,

The velocity of the wind,

Step 2 of 6

The drag force acting on the blimp can be calculated using the formula given below,

(1)

Where,  is the drag coefficient is the density of air.

A is the frontal area of the blimp.

V is the velocity of the wind.

Step 3 of 6

The frontal area of the parachute,

Here,

Substitute the value in the above equation.

The drag coefficient for the balloon is,

Step 4 of 6

From the table properties of air,

The density of air at 1atm pressure and  is,

The velocity of air,

Step 5 of 6

Now, substitute all the known values in equation (1)

Step 6 of 6

Now, rope tension is the sum of rope tension due to the buoyancy effect and the force due to the wind blowing.

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Answer:

[tex]\huge\boxed{\sf V_i=60 \ m/s}[/tex]

Explanation:

Final speed = [tex]V_f[/tex] = 40 m/s

Time = t = 5 s

Acceleration = a = -4 m/s²

Initial velocity = [tex]V_i[/tex] = ?

[tex]\displaystyle a = \frac{V_f-V_i}{t}[/tex]

Put the givens in the above formula

[tex]\displaystyle -4=\frac{40 - V_i}{5} \\\\Multiply \ -5 \ to \ both \ sides\\\\-4 \times 5 = 40 - V_i\\\\-20 =40-V_i\\\\Subtract \ 40 \ to \ both \ sides\\\\-20-40=-V_i\\\\-60\ m/s=-V_i\\\\60 \ m/s = V_i\\\\V_i=60 \ m/s\\\\\rule[225]{225}{2}[/tex]

Magnitude of force experienced by the 90Kg passenger is 450N.

To find the answer, we need to know about the pseudo force.

Pseudo force= 90×5=450N.

Thus, we can conclude that the force experienced by the passenger is 450N.

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The impulse is 13.5 N-s.

As we know that impulse is a sudden force acting on a body for a short time interval is called Impulse.

                                Δp = FΔt  

Mathematically, the change in momentum will equal impulse.

                                Δp = mΔv

                   →           Δp =  0.145(49-(-44))

                   →           Δp = 0.145(93)

                               Δp =  13.5 Newton-second

Thus, option (e) is correct.

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With the use of the second equation of motion formula, the speed the car travelled when the rockets were fired is 12 m/s.

Linear motion depicts movement in a straight line. While speed is the distance travelled per time taken.

Given that In a test run, a rocket-powered car is driving down a test track at a constant speed when the rockets are fired. it then accelerates at 4 m/s2 for 8.0 s covering a distance of 224 m.

The given parameters are;

The speed the car travelled when the rockets were fired can be calculated by using the below formula

s = ut + 1/2a[tex]t^{2}[/tex]

Substitute all the parameters into the formula

224 = 8u + 1/2 x 4 x [tex]8^{2}[/tex]

224 =8u + 2 x 64

224 = 8u + 128

224 - 128 = 8u

8u = 96

u = 96/8

u = 12 m/s

Therefore, the speed the car travelled when the rockets were fired is 12 m/s.

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Answer:

follow me for legitimate answer… oh? U don’t like the feeling of people stealing ur points huh?! Well theirs a taste of your own medicine

Explanation:

The speed with which the ball must be thrown vertically from ground level to rise to a height of 50 m is 31.305 m/s.

Given values:

Maximum height reached from ground level, h_max = 50 m

Final velocity of the ball, v = 0 m/s

Calculation of initial speed of the ball:

Step 1:

Using Newton's third equation of motion, we get:

v² = u² + 2as

where, v is the final velocity of ball

           u is initial velocity of the ball

           a is acceleration of ball

           s is the maximum height attained by the ball

Step 2:

Here, the acceleration of the ball will be given as:

a = -g

  = -9.8 m/s²

where, g is acceleration due to gravity

Applying this value in above equation we get:

v² = u² - 2gh_max

Re-arranging above equation, we get:

u² = v² + 2gh_max

u  =√(v² + 2gh_max)

Step 3:

Applying values in above equation we get:

u  =√((0 m/s)² + 2(9.8 m/s²)(50 m)

   =√980

   = 31.305 m/s

Therefore, the speed with which the ball must be thrown from ground level is 31.305 m/s in order to reach a maximum vertical height of 50 m.

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Answer: 0.000115 seconds

Explanation: how I got this is by first converting the meters to kilometers then I had 160 km/h and 0.0184 km away so then you do 0.0184 divided by 160 (0.0184 / 160) and get 0.000115 seconds.

Due to the Composition, different asteroids reflect different percentages of the light falling on them.

What are Asteroids:

Composition of Asteroids:

We determine reflectivity of asteroids by comparing the brightness of light in the visible spectrum to the brightness of light in the infrared spectrum. The light shining from asteroids is reflected sunlight.

Hence we can say that,

Due to the Composition, different asteroids reflect different percentages of the light falling on them.

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Answer:

The Average Velocity is 2.22m/s.

Explanation:

Average Velocity = displacement(m) ÷ time(s)

8km = 8000m

8km/hr = 2.22m/s

Finding Time

Time = distance÷speed

Time = 8000m ÷ 2.22m/s = 3603.6s = 3604s

Finding Average Velocity

Average Velocity = displacement ÷ time

Average Velocity = 8000m ÷ 3604s

Average Velocity = 2.22m/s

Therefore the Average Velocity is 2.22m/s.

Answer:

The surface tension of plain water can cause a needle to float.

Evidently, the addition of detergent to the water reduces the surface tension of the liquid causing the needle to sink.

When we add detergent to water, the surface tension of water immediately decreases, then the surface tension cannot balance the blade and it will sink.

Surface tension is defined as the phenomenon that occurs when the surface of a liquid is in contact with another phase which may also be a liquid. Liquids obtain the least possible surface area while the surface of the liquid behaves like an elastic sheet.

Surface tension depends not only on the forces of attraction between particles within a given liquid but also on the forces of attraction of the solid, liquid or gas in contact with it where energy is responsible for the occurrence of surface tension, which can be thought of as approximately equal to the work or energy required to remove a surface layer of molecules in a unit area.

When we add soap to water, the surface tension of the water decreases to the point where the surface tension is no longer strong enough to "float" the needle.

Thus, when we add detergent to water, the surface tension of water immediately decreases, then the surface tension cannot balance the blade and it will sink.

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Answer:

Erosion of the surface of Mars.

Explanation:

The surface of Mars have features which were formed as a result of the erosion of the surface of the Mars.

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Answer:

D) 623 N

Explanation:

The vectors' direction is in the North And when we try to take Y and X components Cos(90°) is Zero ... So the X (West) component will be zero

Answer:

-50N/m

Explanation:

Force , F = 15N

Displacement , x = 0.3m

Spring constant , K = ?

K = -F/x

K = -15N/0.3m

K = -50N/m

Answer: 50 N/m

Explanation:

Edge 2022