1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kolezko [41]
3 years ago
12

If a device uses 280 watts of power a day, about how many kilowatt-hours will it use in 30 days?

Physics
1 answer:
Novay_Z [31]3 years ago
6 0

Answer:C

Explanation:

Power=280watts=280/1000 kilowatts

Power=0.28 kilowatts

Device use 0.28 kilowatts in 1 day

1day=24hours

Device use 0.28 kilowatts in 24hours

30days=30 x 24=720 hours

For 720 hours=(0.28x720) ➗ 24

For 720 hours=201.6 ➗ 24

For 720 hours=8.4

You might be interested in
A sphere of radius r = 5cm carries a uniform volume charge density rho = 400 nC/m^3. Q. What is the total charge Q of the sphere
Tanzania [10]

Answer:

The total charge Q of the sphere is 2.094\times10^{-10}\ C.

Explanation:

Given that,

Radius = 5 cm

Charge density J= 400\ nC/m^3

We need to calculate the total charge Q of the sphere

Using formula of charge

q=\rho V

Where, \rho = charge density

V = volume

Put the value into the formula

q=\rho\times(\dfrac{4}{3}\pi r^3)

Put the value into the formula

q=\dfrac{4}{3}\times\pi\times400\times10^{-9}\times(5\times10^{-2})^3

q=2.094\times10^{-10}\ C

Hence, The total charge Q of the sphere is 2.094\times10^{-10}\ C.

6 0
3 years ago
Can someone please explain the quantum theory in simple terms
BaLLatris [955]
Quantum theory is the theoretical basis of modern physics that explains the nature and behavior of matter and energy on the atomic and subatomic level. The nature and behavior of matter and energy at that level is sometimes referred to as quantum physics and quantum mechanics.
6 0
3 years ago
Which word describes the maximum a point moves from its rest position when a wave passes?
Tom [10]

Answer:

Amplitude.

Explanation:

A wave can be defined as a disturbance in a medium that progressively transports energy from a source location to another location without the transportation of matter.

In Science, there are two (2) types of wave and these include;

I. Electromagnetic waves: it doesn't require a medium for its propagation and as such can travel through an empty space or vacuum. An example of an electromagnetic wave is light.

II. Mechanical waves: it requires a medium for its propagation and as such can't travel through an empty space or vacuum. An example of a mechanical wave is sound.

An amplitude can be defined as a waveform that's measured from the center line (its origin or equilibrium position) to the bottom of a trough or top of a crest.

Hence, an amplitude is a word that describes the maximum displacement a point moves from its rest position when a wave passes.

On a graph, the vertical axis (y-axis) is the amplitude of a waveform and this simply means that, it's measured vertically.

Mathematically, the amplitude of a wave is given by the formula;

x = Asin(ωt + ϕ)

Where;

x is displacement of the wave measured in meters.

A is the amplitude.

ω is the angular frequency measured in rad/s.

t is the time period measured in seconds.

ϕ is the phase angle.

6 0
3 years ago
When a cube is inscribed in a sphere of radius r, the length Lof a side of the cube is . If a positive point charge Qis placed a
Nana76 [90]

Answer:

  Ф_cube /Ф_sphere = 3 /π

Explanation:

The electrical flow is

      Ф = E A

where E is the electric field and A is the surface area

Let's shut down the electric field with Gauss's law

       Фi = ∫ E .dA = q_{int} / ε₀

the Gaussian surface is a sphere so its area is

        A = 4 π r²

the charge inside is

        q_{int} = Q

we substitute

       E 4π r² = Q /ε₀

       E = 1 / 4πε₀   Q / r²

To calculate the flow on the two surfaces

* Sphere

       Ф = E A

        Ф = 1 / 4πε₀  Q / r² (4π r²)

        Ф_sphere = Q /ε₀

* Cube

Let's find the side value of the cube inscribed inside the sphere.

In this case the radius of the sphere is half the diagonal of the cube

          r = d / 2

We look for the diagonal with the Pythagorean theorem

         d² = L² + L² = 2 L²

         d = √2 L

         

we substitute

          r = √2 / 2 L

          r = L / √2

          L = √2  r

now we can calculate the area of ​​the cube that has 6 faces

          A = 6 L²

          A = 6 (√2  r)²

          A = 12 r²

the flow is

          Ф = E A

          Ф = 1 / 4πε₀  Q/r²  (12r²)

          Ф_cubo = 3 /πε₀  Q

the relationship of these two flows is

         Ф_cube /Ф_sphere = 3 /π

8 0
4 years ago
Justin Bieber is thrown horizontally at 10.0 m/s from the top of a cliff 122.5 m high.
sveticcg [70]

===>  Distance fallen from rest in free fall =

                                         (1/2) (acceleration) (time²)

                               (122.5 m) = (1/2) (9.8 m/s²) (time²)

Divide each side by (4.9 m/s²):   (122.5 m / 4.9 m/s²)  =  time²

                                                           (122.5/4.9) s²  =  time²

Take the square root of each side:    5.0 seconds


===> (Accelerating at 9.8 m/s², he will be dropping at
                               (9.8 m/s²) x (5.0 s) = 49 m/s
when he goes 'splat'.  We'll need this number for the last part.)


===> With no air resistance, the horizontal component of velocity
doesn't change.

Horizontal distance = (10 m/s) x (5.0 s)  =  50 meters .

===>  Impact velocity =  (10 m/s horizontally) + (49 m/s vertically)

                                 = √(10² + 49²)  =  50.01 m/s  arctan(10/49)

                                 =    50.01 m/s   at  11.5° from straight down,
                                                           
away from the base of the cliff.  

7 0
3 years ago
Read 2 more answers
Other questions:
  • Which statement is not true?
    13·2 answers
  • What happens to the energy of gas particles when an elastic collision takes place?
    5·2 answers
  • After a car's engine has been running for a while, if you stand near the car's engine you can often feel heat coming from the en
    7·1 answer
  • A box slides down a frictionless ramp.if it starts at rest, what is it’s speed at the bottom?
    10·1 answer
  • Which statement best describes perigee?
    6·1 answer
  • A bullet of mass 50 g travelling with a speed of 15ms penetrates into a
    7·1 answer
  • A water balloon is thrown at 20 m/s from the top of a 20 m high building, what is its speed when it hits the ground? Does the an
    5·1 answer
  • Two forces, one four times as large as the other, pull in the same direction on a 10kg mass and impart to it an acceleration of
    7·1 answer
  • a 9.0-kg dog runs at 4.0 m/s and jumps onto a stationary skateboard the mas of the skateboard is 1.0 m/s what speed is the speed
    10·1 answer
  • a car with a mass of 2,00 kg travels a distance of 400 m as it moves from one stoplight to the next . as its fastest , the car t
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!