The volume V of a cube with sides of length x in. is changing with respect to time. At a certain instant of time, the sides of the cube are 7 in. long and increasing at the rate of 0.3 in./s. How fast is the volume of the cube changing (in cu in/s) at that instant of time

Answer:

1. Concave mirror.

2. 4.17 m or 417 cm.

Explanation:

The following data were obtained from the question:

Object distance (u) = 5 m

Magnification (M) = 5

Focal length (f) =..?

1. Identification of the mirror.

To determine whether or not the mirror is concave or convex, we must first of all calculate the image distance.

This can be obtained as follow:

Object distance (u) = 5 m

Magnification (M) = 5

Image distance (v) =.?

Magnification (M) = image distance (v) /object distance (u).

M = v/u

5 = v/5

Cross multiply

v = 5 x 5

v = 25 m

Since the image distance obtained is positive, the mirror is said to be a concave mirror.

2. Determination of the focal length of the mirro.

This can be obtained as follow:

Object distance (u) = 5 m

Image distance (v) = 25 m

Focal length (f) =...?

1/f = 1/v + 1/u

1/f = 1/25 + 1/5

1/f = 0.04 + 0.2

1/f = 0.24

Cross multiply

f x 0.24 = 1

Divide both side by 0.24

f = 1/0.24

f = 4.17 m

Converting the focal length of cm, we have:

1 m = 100 cm

Therefore, 4.17 m = 4.17 x 100 = 417 cm

Therefore, the focal length of the mirror is 4.17 or 417 cm.

Answer:

200 Watts.

Explanation:

Power is defines as the amount of work expended per unit time. Mathematically, it is expressed as Power = Workdone/Time

Given parameters

Energy used up 100Joules

Distance moved by brick = 1 meters

Time taken by the machine = 0.5 secs

Power can also be written as Energy/Time

Required

We need to calculate the amount of power used up.

Power = 100J/0.5s

Power = 100/(1/2)

Power = 100 * 2/1

Power = 200Watts.

This shows that the machine would expend 200Watts of power

Answer:

e_{r} = Δa /a + Δd /Δ d + Δg / g

Explanation:

The error or uncertainty of a quantity is given by several factors, the most direct error is the absolute one that is given by the appreciation of the instruments, when some quantities obtained by a mathematical formula we must know how each error is programmed in the total error, we can see this with the relative error

the calculated quantity is Z

its relative error is

            [tex]e_{r}[/tex] = ΔZ/Z = 1/Z  (dZ /da Δa + dZ /dd Δd + dZ /dg Δg)

            e_{r} = 1 / Z (d /g  Δa + a /g  Δd + ad !1/g²! Δg)

            e_{r} = Δa /a + Δd /Δ d + Δg / g

notice that we take the worst case.

The measured quantities have absolute errors Da, Dd, Dg

Answer:

Flexibility Increases

Pre-breathe time decreases

Mass of suit decreases.

Explanation:

Spacesuits are designed for space shuttles when a person goes to explore the galaxy. The spacesuits shuttle era are pressurized at 4.3 pounds per inch. The gas in the suit is 100% of oxygen and there is more oxygen to breathe when the altitude of 10,000 is reached. This will decrease the breathing time and mass of suit.

Answer:

It is a finite resource.

Explanation:

A nonrenewable resource is a natural substance that is not replenished with the speed at which it is consumed. Fossil fuels such as oil, natural gas, and coal are examples of nonrenewable resources.

Answer:

Coal, oil, natural gas.

Explanation:

Non renewable resource -A non-renewable resource (also called a finite resource) is a natural resource that cannot be readily replaced by natural means at a quick enough pace to keep up with consumption.

Coal, oil, and natural gas are all examples of non-renewable resources and cannot be readily replaced to keep up with consumption.

Answer:D

Explanation:

Apex

Explanation:

In case the resistors are in series

R =R1 + R2

R = 40 ohm + 40 ohm

R = 80 ohm

In case the resistors are in parallel

R = 1/R1 + 1/R2

R = 1/40 + 1/40

R = 2/40 ohm

R = 1/20 ohm or R = 0.05 ohm

dont forget to mark brainliest

Answer:

dtwtwerEtbWt

Explanation:

bwtrbtWbTW4TBW4tbW4T4t

Answer:

Explanation:

A ) Let the angle be θ between magnetic field and velocity of charged particle

Force created on charged particle F

= Bqv sinθ, B is magnetic field , q is charge , v is velocity of charged particle

F = .05 x 2 x 10⁻⁶ x 10⁸ x sinθ

8 = 10 sinθ

sinθ = .8

θ =  53°.

B )

acceleration = force / mass

= 8 / 10⁻²⁰

= 8 x 10²⁰ m / s²

Answer:

(a) The projectile takes approximately 4.420 seconds to reach the water, (b) The horizontal scope of the projectile is 1591.2 meters, (c) The remaining height to descend after 2 seconds of being launched is 63.624 meters.

Explanation:

The projectile experiments a parabolic motion, where horizontal speed remains constant and accelerates vertically due to the gravity effect. Let consider that drag can be neglected, so that kinematic equation are described below:

[tex]x = x_{o}+v_{o,x} \cdot t[/tex]

[tex]y = y_{o} + v_{o,y}\cdot t +\frac{1}{2}\cdot g \cdot t^{2}[/tex]

Where:

[tex]x_{o}[/tex], [tex]y_{o}[/tex] - Initial horizontal and vertical position of the projectile, measured in meters.

[tex]v_{o,x}[/tex], [tex]v_{o,y}[/tex] - Initial horizontal and vertical speed of the projectile, measured in meters per second.

[tex]t[/tex] - Time, measured in seconds.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

[tex]x[/tex], [tex]y[/tex] - Current horizontal and vertical position of the projectile, measured in meters.

Given that [tex]x_{o} = 0\,m[/tex], [tex]y_{o} = 80\,m[/tex], [tex]v_{o,x} = 360\,\frac{m}{s}[/tex], [tex]v_{o,y} = 0\,\frac{m}{s}[/tex] and [tex]g = -9.807\,\frac{m}{s^{2}}[/tex], the kinematic equations are, respectively:

[tex]x = 360\cdot t[/tex]

[tex]y = 80-4.094\cdot t^{2}[/tex]

(a) If [tex]y = 0\,m[/tex], the time taken for the projectile to reach the water is:

[tex]80 - 4.094\cdot t^{2} = 0[/tex]

[tex]t = \sqrt{\frac{80}{4.094} }\,s[/tex]

[tex]t \approx 4.420\,s[/tex]

The projectile takes approximately 4.420 seconds to reach the water.

(b) The horizontal scope is the horizontal distance done by the projectile before reaching the water. If [tex]t \approx 4.420\,s[/tex], the horizontal scope of the projectile is:

[tex]x = 360\cdot (4.420)[/tex]

[tex]x = 1591.2\,m[/tex]

The horizontal scope of the projectile is 1591.2 meters.

(c) If [tex]t = 2\,s[/tex], the height that remains to descend is:

[tex]y = 80-4.094\cdot (2)^{2}[/tex]

[tex]y = 63.624\,m[/tex]

The remaining height to descend after 2 seconds of being launched is 63.624 meters.

Answer:

if it's velocity u talking of.....

Explanation:

then it's displacement/ time

Answer: 14000 N

Explanation: i just did it on khan academy

Answer:

  1.9 km​

Explanation:

The equation for vertical motion is ...

  h(t) = -4.9t^2 +26t +20

This will have a zero near t = 5.988 seconds.*

The horizontal distance traveled in that time is ...

  (310 m/s)(5.988 s) ≈ 1856 m ≈ 1.9 km

_____

* The root of a quadratic can be found numerous ways. We choose the quick and easy: let a graphing calculator show it to you.

Answer;

Motion: A body is said to be in motion if it changes its position with respect to its surroundings.

Explanation:

Rest and motion are the relative terms because they depend on the observer's frame of reference. So if two different observers are not at rest with respect to each other, then they too get different results when they observe the motion or rest of a body .

one example for each. Rest: If a body does not change its position with respect to its surroundings, the body is said to be at rest. ... Motion: A body is said to be in motion if it changes its position with respect to its surroundings.

Answer:

a = 85.9 m / s²

Explanation:

For this exercise we can use Newton's second law in the most compressed part

             F - W = m a

force is the spring elastic force

             F = - k Δx

          k Δx - m g = m a

          a = k/m  Δx - g

         Δx = x₀ -[tex]x_{f}[/tex]

         ΔX = 46 - 5 = 41cm (1m / 100cm) = 0.41  m

let's calculate

          a = 1.4 10⁴/60 0.41 - 9.8

          a = 85.9 m / s²

Answer:

acceleration is the answer

Answer:

Acceleration

Explanation:

Answer:

5.23 C

Explanation:

The current in the wire is given by I = ε/R where ε = induced emf in the wire and R = resistance of wire.

Now, ε = -ΔΦ/Δt where ΔΦ = change in magnetic flux = AΔB and A = area of loop and ΔB = change in magnetic field intensity = B₂ - B₁

B₁ = 0.670 T and B₂ = 0 T

ΔB = B₂ - B₁ = 0 - 0.670 T = - 0.670 T

A = πD²/4 where D = diameter of circular loop = 13.2 cm = 0.132 m

A = π(0.132 m)²/4 = 0.01368 m² = `1.368 × 10⁻² m²

ε = -ΔΦ/Δt = -AΔB/Δt = -1.368 × 10⁻² m² × (-0.670 T)/Δt= 0.9166 × 10⁻² Tm²/Δt

Now, the resistance R of the circular wire R = ρl/A' where ρ = resistivity of copper wire =  1.68 x 10⁻⁸ Ω.m, l = length of wire = πD and A' = cross-sectional area of wire = πd²/4 where d = diameter of wire = 2.25 mm = 2.25 × 10⁻³ m

R = ρl/A' = 1.68 x 10⁻⁸ Ω.m × π × 0.132 m÷π(2.25 × 10⁻³ m)²/4 = 0.88704/5.0625 = 0.1752 × 10⁻² Ω = 1.752 × 10⁻³ Ω

So, I = ε/R = 0.9166 × 10⁻² Tm²/Δt1.752 × 10⁻³ Ω  

IΔt = 0.9166 × 10⁻² Tm²/1.752 × 10⁻³ Ω = 0.5232 × 10 C

Since ΔQ = It = 5.232 C ≅ 5.23 C

So the charge is 5.23 C

The induced emf through wire depends on the current flow (indirectly with charge flow as well).

The value of charge moving past a point in the coil during its operations is 5.23 C.

The region in a space where a particle experiences some magnetic force, is known as the magnetic field.

Given data -

The diameter of the circular loop is, d = 13.2 cm = 0.132 m.

The change in magnetic field strength is, ΔB = 0.670 T.

The new diameter of the wire is, d' = 2.25 mm = 2.25 × 10³ m.

The resistivity of the wire is, [tex]\rho = 1.68 \times 10^{-8} \;\rm \Omega.m[/tex].

The current in the wire is given by the following expression,

I = ε/R

Here,

ε is the induced emf in the wire.

R is the resistance of the wire.

And the expression for the induced emf of the wire is given as,

ε = -ΔΦ/Δt

Here,

ΔΦ is the change in magnetic flux. And its expression is,

ε = A × ΔB

Here,

A is the area of the loop. And its value is, A = πd²/4.

Solving as,

A = π(0.132 m)²/4

A = 0.01368 m²
A = `1.368 × 10⁻² m²

Now, calculating the induced emf as,

ε = ΔΦ/Δt

ε = A × ΔB/Δt

ε = 1.368 × 10⁻² m² × (0.670 T)/Δt

ε = 0.9166 × 10⁻² Tm²/Δt

Now, the resistance R of the circular wire is,

R = ρ × L/A'

Here,

L is the length of the wire and its value is. L = πd .

And A' is the new cross-sectional area of wire,

A' = πd'²/4

So, the resistance is,

R = ρ × L/A'

R = 1.68 x 10⁻⁸  ×( π × 0.132 m) ÷ π(2.25 × 10⁻³ m)²/4 =

R = 0.88704/5.0625

R = 0.1752 × 10⁻² Ω

R = 1.752 × 10⁻³ Ω

Now, the current flow (I) in the wire is given as,

I = ε/R

I = 0.9166 × 10⁻² Tm²/Δt1.752 × 10⁻³ Ω  

And obtaining the value of charge from the expression of current as,

Q = IΔt
Q = 0.9166 × 10⁻² Tm²/1.752 × 10⁻³ Ω

Q = 0.5232 × 10 C

Q = 5.23 C

Thus, we can conclude that the value of charge moving past a point in the coil during its operations is 5.23 C.

Learn more about the resistance of a wire here:

https://brainly.com/question/15067823

Answer:

Time seem to flow only in one direction because if it started to go in backward direction that would break the second law of thermodynamics. We do not find time to be moving in any direction because time is not an object that can move nor is it a force that can move any object.

Answer:

less

Explanation:

Sliding friction is always less than static friction. This is because in sliding friction, the bodies slide with each other and thus the effect of friction is not more. However, it does not happen in the case of static friction.

Answer:

V=-8.35v

Explanation:

Pls see attached file

Answer:

   f = 6.37 Hz,       T = 0.157 s

Explanation:

The expression you have is

       y = 5 sin (3x - 40t)

this is the equation of a traveling wave, the general form of the expression is

      y = A sin (kx - wt)

where A is the amplitude of the motion, k the wave vector and w the angular velocity

Angle velocity and frequency are related

         w = 2π f

         f = w / 2π

from the equation w = 40 rad / s

        f = 40 / 2π

        f = 6.37 Hz

frequency and period are related

       f = 1 / T

       T = 1 / f

       T = 1 / 6.37

       T = 0.157 s

Answer:

The object would weight 63 N on the Earth surface

Explanation:

We can use the general expression for the gravitational force between two objects to solve this problem, considering that in both cases, the mass of the Earth is the same. Notice as well that we know the gravitational force (weight) of the object at 3200 km from the Earth surface, which is (3200 + 6400 = 9600 km) from the center of the Earth:

[tex]F_G=G\,\frac{M_E\,m}{d^2} \\28\,\,N=G\,\frac{M_E\,m}{9600000^2}[/tex]

Now, if the body is on the surface of the Earth, its weight (w) would be:

[tex]F_G=G\,\frac{M_E\,m}{d^2} \\w=G\,\frac{M_E\,m}{6400000^2}[/tex]

Now we can divide term by term the two equations above, to cancel out common factors and end up with a simple proportion:

[tex]\frac{w}{28} =\frac{9600000^2}{6400000^2} \\\frac{w}{28} =\frac{9}{4} \\\\ \\w=\frac{9\,*\,28}{4}\,\,\,N\\w=63\,\,N \\[/tex]

Answer:

Explanation:

1. A parsec is defined as the distance from the Sun which would result in a parallax of_TWO____ arcsecond as seen from Earth when observed 6 months apart.

2. One parsecs is about_3.3____light years

3. The more distant a star, the_LESS ____its parallax.

4. The statement "we can measure stellar parallax for most stars in our galaxy" is__TRUE .___.

5. The closest stars have parallaxes smaller than_.002 _____arcsecond.

6. The first successful measurements of stellar parallax were made by_Friedrich Bessel_____in year_1838_____for the star named.

7. Star Fred has parallax four times greater than star Bob. Star Fred is__4____times_nearer_____than star Bob.

Answer:

v = 6t² + t + 2, s = 2t³ + ½ t² + 2t

59 m/s, 64.5 m

Explanation:

a = 12t + 1

v = ∫ a dt

v = 6t² + t + C

At t = 0, v = 2.

2 = 6(0)² + (0) + C

2 = C

Therefore, v = 6t² + t + 2.

s = ∫ v dt

s = 2t³ + ½ t² + 2t + C

At t = 0, s = 0.

0 = 2(0)³ + ½ (0)² + 2(0) + C

0 = C

Therefore, s = 2t³ + ½ t² + 2t.

At t = 3:

v = 6(3)² + (3) + 2 = 59

s = 2(3)³ + ½ (3)² + 2(3) = 64.5

Answer:

2000 cm³

Explanation:

Assuming the pressure is constant:

V / T = V / T

1000 cm³ / 300 K = V / 600 K

V = 2000 cm³

The only thing that mkes this question inconvenient is that it uses a mixture of units ... speed in km/hr, and acceleration in m/s².  You can't directly mash those together.

What's the speed when we express it in m/s ?

Speed = (90 km/hr) · (1,000 m/km) · (1 hr/3,600 sec)

Speed = (90 · 1,000 · 1 / 3,600) · (km-m-hr / hr-km-sec)

Speed = 25 m/s

OK great !  

-- The car is traveling at 25 m/s when the brakes are applied.

-- The brakes slow it down by 0.5 m/s every second.

-- So it takes (25/0.5) = 50 seconds to stop the car.

-- During that time, the car's average speed is (1/2)·(25m/s + 0) = 12.5 m/s .

-- Moving at an average speed of 12.5 m/s for 50 sec, the car travels

(12.5 m/s) · (50 s)  =  625 meters

Answer:

1 j

2 C

3 H

4E

5A

Explanation:

Answer:

a)  v = 2.21 10⁷ m / s, b)  B = 6.04 10⁻⁴ T , c)  f = 1.69 10⁷ Hz , d)     T = 5.9 10⁻⁸ s

Explanation:

a) For this exercise, let's start by using the concept of kinetic energy

           K = ½ m v²

           v = √ 2K / m

Let's reduce the magnitudes to SI units

          E = K = 1.39 kev (1000 eV / 1 keV) (1.6 10⁻¹⁹ J / 1 eV) = 2,224 10⁻¹⁶ J

          r = 20.8 cm (1 m / 100 cm) = 0.208 m

let's calculate

          v = √ (2 2,224 10⁻¹⁶ / 9.1 10⁻³¹)

          v = √ (4.8879 10¹⁴)

          v = 2.21 10⁷ m / s

b) let's use Newton's second law where the force is magnetic

              F = m a

where the acceleration is centripetal

              a = v² / r

the magnetic force is

              Fm = q v x B = q v B sin θ

since the circle is perpendicular to the magnetic field, the angle is 90º and the sine is equal to one, let's substitute

          qv B = m v² / r

          B = m v / rq

let's calculate

          B = 9.1 10⁻³¹ 2.21 10⁷ / (0.208  1.6 10⁻¹⁹)

          B = 6.04 10⁻⁴ T

c) Linear and angular variables are related

          v = w r

          w = v / r

          w = 2.21 10⁷ / 0.208

          w = 1.0625 10⁸ ras / s

    angular velocity and frequency are related

          w = 2π f

          f = w / 2π

          f = 1.0625 10⁸ / (2π)

          f = 1.69 10⁷ Hz

d) the frequency is the inverse of the period

          f = 1 / T

          T = 1 / 1.69 10⁷

           T = 5.9 10⁻⁸ s

Answer:

Length contraction

A moving object traveling at a velocity approaching the speed of light will appear to be shorter or to have undergone contraction.

The proportion by which the object is observed to have contracted is given by Lorentz transformation as follows;

[tex]L = L_{0}\cdot \sqrt{1 -\dfrac{v^{2}}{c^{2}}}= \dfrac{L_{0}}{\gamma }[/tex]

Time dilation

As the relative speed of motion of an object approaches the speed of light, the clock in the frame in motion will be observed to be moving slowly or dilated in a proportion given by Lorentz transformation as follows;

[tex]T = \dfrac{T_{0}}{\sqrt{1 -\dfrac{v^{2}}{c^{2}}}}[/tex]

Explanation:

Example of length contraction example

Two square boxes of side length L which are travelling at a velocity of 0.9 × c, are going to arranged in a single box of side side length  L according to length contraction Lorentz transformation, to  stationary observer we have

[tex]2 \times L\cdot \sqrt{1 -\dfrac{(0.9 \cdot c)^{2}}{c^{2}}}= 0.8 \cdot L[/tex]

To the stationary observer, the 2 boxes of length L will fit side by side in the single box of length L, while to those on the space ship carrying the boxes, the size of the single box is  [tex]L\cdot \sqrt{1 -\dfrac{(0.9 \cdot c)^{2}}{c^{2}}}= 0.4 \cdot L[/tex], which will not contain half of one box

Example of of time dilation example

Twin A of two twins, twin A and B went on a space journey at the speed of 0.87·c for 5 years, the number of years past for twin B when they meet again will be [tex]T = \dfrac{5}{\sqrt{1 -\dfrac{(0.87\cdot c)^{2}}{c^{2}}}} = 10.14 \ years[/tex]

Answer:

radio waves, micro wave, x-rays

Explanation:

Explanation:

A MAGNET IN WHICH MAGNETIC FIELD IS PRODUCED BY ELECTRIC CURRENT IS CALLED ELECTROMAGNET.

THE ELECTROMAGNETS ARE HAVE 3 TYPES. THERE ARE:

◇ ROBUST ONES

◇ THE SUPERCONDUCTORS

◇ HYBRIDS.

Answer:

Explanation:

We shall apply work energy theorem to calculate the initial velocity just after the collision .

Their kinetic energy will be equal to work done by friction .

force of friction = μ mg , where μ is coefficient of friction , m is total mass and g is acceleration due to gravity

force = .463 x 3210 x 9.8

= 14565.05 N

work done = force x displacement

= 14565.05 x 14.54 = 211775.88 J

now applying work energy theorem

1/2 m v² = 211775.88 , m is composite mass , v is velocity just after the collision

.5 x 3210 x v² = 211775.88

v² = 131.94

v  11.48 m /s