What is at the very center of our galaxy? This question is difficult to answer because the center is completely obscured to our eyes behind a large amount of dust. On the basis of what you know about dust from previous chapters, what can be done to improve our view of the galaxy’s center?

Answer:

The total frictional force equals 60 N

Explanation:

We know that F - f = ma where F is the applied force, f is the frictional force, m the mass of the object and a its acceleration.

Now, since the cart moves with constant velocity, its acceleration is zero. So, a = 0.

So F - f = ma

F - f = m(0) = 0

F - f = 0

So, F = f

From the above, we see that the frictional force equals the applied force which is equal to 60 N.

So, f the total frictional force equals 60 N

Answer:

a) tangent ; b) 153.88 yds ; c) No , less than or equal to 45° ; D) 45°

Explanation:

Given the following ;

From the triangle sketch :

Base length = 50 yards

Angle of elevation = 72°

a. Which trigonometric ratio would you use to calculate how high the blimp will be above the 50 yard line?

Using trigonometry :

The height of the blimp will be calculated using :

Tangent :

Tan θ = opposite / Adjacent

B.) How high above the ground is the blimp?

Using :

Tan θ = opposite / Adjacent

Θ = 72° ; adjacent = 52, opposite = height(h)

Tan 72° = h / 50

h = 3.0776835 * 50

h = 153.88 yds

C.) In order to be able to read the advertisement on the side of the blimp the highest the blimp can be is 150 feet. Will the fans be able to read the advertisement?

1 yard = 3 Feets

153.88 yards = 3 * 153.88

= 461.65 feets

No, because the height of the blimp is 461.65 Feets which is greater than 150 Feets.

To make viewing possible, the angle of elevation should be:

50 yards is equivalent to (3 * 50) = 150 feets

Max imum Height of blimp = 150 Feets

From pythagoras ;

Tanθ = 150 Feets / 150 Feets

Tanθ = 1

θ = tan^-1(1)

θ = 45°

To make viewing advertisement possible, angle of elevation should not exceed 45°

d.)If height of blimp is 150 Feets, then the exact angle of elevation will be 45°

Answer:

D. Displacement

Explanation:

got it right on edge

Average velocity is different than average speed because calculating average velocity involves Displacement, therefore the correct option is option D.

The total displacement covered by any object per unit of time is known as velocity. It depends on the magnitude as well as the direction of the moving object.  It can also be represented by the infinitesimal rate of change of displacement with respect to time. The unit of velocity is meter/second.

The mathematical expression for velocity is given by

velocity= displacement  / time taken

In the displacement time graph the slope of the curve represent the velocity of the object ,the rate of change of velocity is known as the acceleration of the object .

In the velocity time graph the slope of the curve represent the acceleration of the body, The unit of acceleration is metre per second Square

The total distance traveled by an object is different than the total displacement covered by it because the displacement is a vector quantity and it is calculated on the basis of the shortest distance traveled by the body or object.

The main difference between the distance and the displacement is that displacement can be positive or negative or zero but distance can never be negative.

Let’s understand understand with example of average velocity ,suppose an object is moving with 200 m displacement covered in a time of 15 seconds then the average velocity of the object is 13.33 m/s.

Thus, average velocity is different than average speed because calculating average velocity involves Displacement, therefore the correct option is option D.

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Answer:

Package's vertical displacement(s) = 22.12 meter

Explanation:

Given:

Speed of plane = 120 m/s

Total distance = 255 m

Find:

Package's vertical displacement(s)

Computation:

Time taken = Distance / Speed

Time taken = Total distance / Speed of plane

Time taken = 255 / 120

Time taken = 2.125 s

Acceleration due to gravity(g) = 9.8 m/s²

Initial velocity (u) = 0

So,

Package's vertical displacement(s) = ut + (1/2)gt²

Package's vertical displacement(s) = (0)(2.125) + (1/2)(9.8)(2.125)²

Package's vertical displacement(s) = 22.12 meter

Answer: -22.1

Explanation:

I just did the Khan Academy and that was the answer, not the one provided by that one person. :)))

Answer:

False

Explanation:

Total internal reflection is a condition that occurs when light travels from dense medium to less dense medium.

From the table given in the question above,

Refractive Index of Whale oil = 1.460

Refractive Index of vacuum = 1

From the above, we can see that the whale oil has a higher Refractive Index than vacuum. This implies that the whale oil is denser than the vacuum.

Therefore, total internal reflection will occur when light travels from whale oil to vacuum because the whale oil is denser than the vacuum.

Answer:

1666.7 ETB (birr)

833.3 ETB (birr)

2083.3 ETB (birr)

Explanation:

The first worker

5000*1/3=1666.7

The second worker

5000*1/6=833.3

The third worker

5000*5/12=2083.3

Hope this helps :) ❤❤❤

Answer:

Hydrogen used in fuel cells has the energy to weight ratio ten times greater than lithium-ion batteries. Consequently, it offers much greater range while being lighter and occupying smaller volumes. It can also be recharged in a few minutes, similarly to gasoline vehicles.

Answer:

Explanation:

just use the gravational force equation which is G x m of earth x m of object divided by r squared (which is radius of earth)

The current does not change.

All three resistors are connected directly to the power source, and are unaware of each other.

Answer:

a)4500V

b)750V

Explanation:

Given:

Distance between the plate=

6.00 cm

We need to convert to m

Then the Distance between the plate=

0.06m

electric field strength between two parallel plates =

7.50 × 104 V/m .

Then E= 7.50 × 104 V/m .

(a) What is the potential difference between the plates?

potential difference between the plates can be calculated using the formula below

Δ Vab=ED

Where E is the given electric field strength

D= The Distance between the plate

ΔVab=7.50 × 10⁴V/m ×

0.06m

= 4500V

(b) The plate with the lowest potential is taken to be zero volts. What is the potential 1.00 cm from that plate and 6.00 cm from the other?

the potential 1cm from the zero volt plate

Then the 1cm must be converted to m

= 0.01m

Let us say plate A as the plate at 0 volts:

The potential increases linearly going from plate A (0 V) to plate B (4500V).

Therefore,if the potential difference between A and B, separated by 6 cm, is 4500 V, then the potential difference between A and a point located at 1 cm from A is can be calculated also

If the plate with Lowest potential is taken to be zero then

=ΔVab=Vab-Vb=Va-0=Va=ED

Va=7.50 × 10⁴V/m × 0.01=750V

Answer:

λ₀ = 2 d n

Explanation:

A soap film is a layer where the lus is reflected on the surface and on the inside of the film, these two reflected rays can interfere with each other either constructively or destructively.

Let's analyze the general conditions of this interference,

* When the ray of light reaches the surface of the film it is reflected, as the index of refraction of the air is less than the index of the film, the reflected ray has a phase change of 180º

* When the ray penetrates the film, its wavelength changes due to the refractive index of the film.

          λ = λ₀ / n

where lick is the wavelength in the vacuum or air and n index of refraction of the film, in general this interference is observed perpendicular to the film, so the sine veils 1. the expression for constructive interference taking in what previous remains

         2d = (m + ½) λ

the expression for destructive interference remains

         2d = m λ

          2d = m λ₀ / n

When the film is placed on a glass plate whose index of refraction is greater than the index of refraction of the film, in the reflection in the lower part of the film another phase difference of 180º is created, for which we have a difference of total phase of 180 +180 = 360º, which is equivalent to no phase difference, therefore the two previous equations are interchanged.

Therefore where we had destructive interference now a cosntructive interference happens we can see the reflected light.

Find us the wavelength that this constructive interference creates

           2d n = m λ₀

           λ₀ = 2 d n / m

To find the minimum wavelength, suppose we observe the first interference pattern m = 1

         λ₀ = 2 d n

where d is the thickness of the film and n the index of refraction of the same

Answer:

Explanation:

We shall apply law of conservation of momentum to know velocity after collision . Let it be v .

total momentum before collision = total momentum after collision

15 x 1.5 - 12 x .75 = ( 15 + 12 ) v

v = .5 m /s

kinetic energy before collision

1/2 x 15 x 1.5² + 1/2 x 12 x .75²

= 16.875 + 3.375

= 20.25 J

kinetic energy after collision

= 1/2 x ( 15 + 12 ) x .5²

= 3.375 J

Loss of energy = 16.875 J

This energy appear as heat and sound energy that is produced during collision .

Answer:

Q1 acceleration = 16m/s²

Q2 Net force = 9N North

Explanation:

Q1 Using the formula F=ma

Q2 R = F1 + F2

ANSWER

C 11.5 m/s

EXPLANATION

Answer:

11.5m/s south

Explanation:

Online classes

Answer:

Explanation:

For entropy change the formula is

ΔS = ΔQ / T

ΔQ = Δ H

ΔS = Δ H / T

Given

Δ H = + 162.8 kJ

We can take equilibrium temperature as average temperature of the whole process

So, T = 273 + 87 = 360 K

ΔS = Δ H / T

=  162.8 kJ  / 360

= +  0.508 kJ / K .

When the magnitude of the heat transfer for the process is 162.8 kJ, Then the entropy change for the mixing process, in kJ/K is = + 0.508 kJ / K

For The entropy change, the formula is

Then ΔS = ΔQ / T

After that ΔQ = Δ H

Then ΔS = Δ H / T

Given as per question are:

Then Δ H = + 162.8 kJ

Now We can take equilibrium temperature as average temperature of the whole process are:

So, T is = 273 + 87 = 360 K

Then ΔS = Δ H / T

After that = 162.8 kJ / 360

Therefore, = + 0.508 kJ / K.

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Answer:

tension is how much force is being exerted on each end of the string, whereas length is how long the string is. So assuming that the string has finite mass, then the tension on the string should increase proportionally to the string according to Newton's law f=ma.

Explanation:

Answer:

73.8 km/h

Explanation:

The velocity of object A relative to object B is:

v = va − vb

Let's say east is +x and north is +y, and angles are measured from +x.

The velocity of the first car in the x direction is:

18 km/h cos 135° = -9√2 km/h

The velocity of the first car in the y direction is:

18 km/h sin 135° = 9√2 km/h

The velocity of the second car in the x direction is:

60 km/h cos 270° = 0 km/h

The velocity of the second car in the y direction is:

60 km/h sin 270° = -60 km/h

The relative velocity in the x direction is:

vₓ = -9√2 km/h − 0 km/h = -9√2 km/h ≈ -12.7 km/h

The relative velocity in the y direction is:

vᵧ = 9√2 km/h − (-60 km/h) = 9√2+60 km/h ≈ 72.7 km/h

The speed, or magnitude of the velocity, is:

v = √(vₓ² + vᵧ²)

v = √((-12.7 km/h)² + (72.7 km/h)²)

v ≈ 73.8 km/h

Answer:

        v = √k/m    x

Explanation:

We can solve this exercise using the energy conservation relationships

starting point. Fully compressed spring

        Em₀ = [tex]K_{e}[/tex] = ½ k x²

final point. Cart after leaving the spring

        [tex]Em_{f}[/tex] = K = ½ m v²

        Em₀ = Em_{f}

        ½ k x² = ½ m v²

        v = √k/m    x

Answer:

The teacher should swim in a direction 29.24° North of East

Explanation:

Given that the there is a water  current across the lake, and the physics teacher intends to swim directly across the lake, the direction the physics teacher will have to swim is found as follows;

The speed of the water current is given by the speed of the floating leaf traveling with the water current  

Distance traveled by the leaf = 4.2 m South

Time of travel of the leaf = 5.0 s

Speed of leaf = 4.2/5 = 0.84 m/s = Speed of the water current

Swimming peed of the teacher, v = 1.9 m/s

To swim directly across the lake, the teacher has to swim slightly in the opposite direction of the water current, the y-component of the teacher's swimming speed should be equal to and opposite that of the speed of the water current.

Y-component of v = v×sin(θ), where θ is the angle of the direction, the teacher should swim

Therefore;

1.9 × sin(θ) = 0.84

sin(θ) = 0.84/1.9 = 0.44

θ = 26.24°

That is the teacher should swim in a direction 29.24° North of East.

To cross the lake the teacher has to swim in a direction 29.24° North of the East

The speed of the water current can be derived from the speed of the floating leaf :

The distance traveled by the leaf L = 4.2 m South

Time taken T = 5s

So, the speed of the leaf is:

u = 4.2/5

u = 0.84 m/s South

So, the speed of the current is 0.84 m/s South

Now, it is given that the speed of the teacher is, v = 1.9 m/s East

To cross the lake the speed of the teacher must be in a Northeast direction so that the North component of the speed of the teacher cancels out the speed of the current which is directed towards the South.

Let, the speed of the teacher makes an angle of θ from the EAST.

So, the North component is given by:

v(north) = vsinθ

it must be equal to the speed of the current:

vsinθ = u

1.9 × sinθ = 0.84

sinθ = 0.84/1.9

sinθ = 0.44

θ = 26.24°

The teacher should swim in a direction 29.24° North of East.

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Answer:

Because ocean tides are the effect of ocean water responding to a gravitational gradient, the moon plays a larger role in creating tides than does the sun. But the sun's gravitational gradient across the earth is significant and it does contribute to tides as well.

i hope this help i

i try to explain and like i sayed i hope this help u.

Answer:

the moon

Explanation:

ive passed the grade you learned this in

Answer:

[tex]\boxed{\mathrm{Density = 1.1 \ g/cm^3}}[/tex]

Explanation:

Volume of fresh water:

Volume = Mass / Density

Volume = 1600/1

[tex]V_{1}[/tex] = 1600 cm³

Volume of sea water:

Volume = Mass / Density

Volume = 1200/1.2

Volume = 1000 cm³

So,

Total Volume when they are mixed = 1600+1000

Total Volume when they are mixed = 2600 cm³

And,

Total Mass when they are mixed = 1600+1200

Total Mass when they are mixed = 2800 g

Now, Measuring the density of the mixture:

Density = Mass / Volume

Density = 2800/2600

Density = 1.1 g/cm³

Answer:

[tex]\mathrm{1.086 \: g/cm^3 }[/tex]

Explanation:

Volume of fresh water ⇒ 1600 cm³

Density of fresh water ⇒ 1 g/cm³

Volume of sea water ⇒ 1200 cm³

Density of sea water ⇒ 1.2 g/cm³

[tex]density=\frac{mass}{volume}[/tex]

[tex]mass=density \times volume[/tex]

Calculate mass of fresh water.

[tex]m=1600 \times 1[/tex]

[tex]m=1600 \: g[/tex]

Calculate the mass of sea water.

[tex]m=1200 \times 1.2[/tex]

[tex]m=1440 \: g[/tex]

Find the density of the mixture.

[tex]density=\frac{mass}{volume}[/tex]

[tex]\rho = \frac{1600+1440}{1600 + 1200}[/tex]

[tex]\rho = \frac{3040}{2800}[/tex]

[tex]\rho= 1.0857...[/tex]

Answer:

Explanation:

Load ( L ) = 500 N

Effort ( E ) = 200 N

Load distance ( LD ) = 3 m

Effort distance ( ED ) = ?

Now, Let's find the Effort distance ( ED )

We know that,

Output work = Input work

i.e L × LD = E × ED

plug the values

[tex]500 \times 3 = 200 \times ED[/tex]

multiply the numbers

[tex]1500 = 200 \times ED[/tex]

Swipe the sides of the equation

[tex]200 \: ED \: = 500[/tex]

Divide both sides of the equation by 200

[tex] \frac{200 \: ED}{200} = \frac{500}{200} [/tex]

Calculate

[tex]ED\: = 2.5 \: m[/tex]

Hope this helps..

best regards!!

Answer:

20 m

Explanation:

Given:

v = 0 m/s

a = -10 m/s²

t = 4 s / 2 = 2 s

Find: Δy

Δy = vt − ½ at²

Δy = (0 m/s) (2 s) − ½ (-10 m/s²) (2 s)²

Δy = 20 m

Answer:

8996kg*m/s/s

Explanation:

Given:

a=26m/s/s

m=346kg

Required:

f=?

Formula:

f=m*a

Solution:

f=346kg*26m/s/s

f=8996kg*m/s/s

Hope this helps ;) ❤❤❤

Answer:

[tex]\boxed{F = 8996 \ Newton}[/tex]

Explanation:

Given:

Mass = m = 346 kg

Acceleration = a = 26 m/s²

Required:

Force = F = ?

Formula:

F = ma

Solution:

F = 346 * 26

F = 8996 Newton

Answer:

3.5 kg

Explanation:

use the equation; (m1v1i) + (m2v2i) = (m1v1f) + (m2v2f)

= m1(0) - m1v1f = m2v2f - m2(0)

= (-2.0)(15)/-20

= 1.5 kg

then add the other piece (2.0kg)

1.5 + 2.0 = 3.5 kg

The mass of firework before explosion is 3.50kg.

mass flying to right  m1 = 2kg

                                v1  = 15 m/s

mass flying to left m2  = ?

                                v2 = - 20m/s

 initial velocity u = 0

by conservation of linear momentum

m1v1+ m2v2 = (m1+m2 ) u

2x 15- m2x 20 = 0

                 m2 = 1.50kg

therefore mass of firework before explosion

                   m1+m2

                     2+ 1.50

                  = 3.50kg

Mass is the amount of matter in a physical body. It  also measures the body's inertia, the resistance to acceleration when a net force is applied. The mass of an object also determines  its gravitational force on other objects. The basic SI  unit of mass is the kilogram.

Body mass is always constant. One way to calculate mass:

mass = volume × density. Weight is a measure of the gravitational force acting on a mass. The SI unit of mass is the "kilogram".

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Answer: 43.2 J

Explanation:

Work = change in KE

initial KE = 0

final KE = 1/2mv^2 = 1/2(0.370 kg)(15.2778 m/s)^2 = 43.2 J

i'm not sure about sig figs though

Answer:

Explanation:

Given,

Force ( f ) = 30 N

Acceleration(a) = 7.6 m/s

Now, Let's find the mass of the ball

Using the Newton's second law of motion:

We get:

[tex]force \: = mass \: \times acceleration[/tex]

plug the value

[tex]30 \: = m \: \times 7.6[/tex]

Use the commutative property to reorder the terms

[tex] 30 = 7.6 \: m[/tex]

Swap the sides of the equation

[tex]7.6m = 30[/tex]

Divide both sides of the equation by 7.6

[tex] \frac{7.6 \: m}{7.6} = \frac{30}{7.6} [/tex]

Calculate

[tex]m = 3.94 \: kg[/tex]

Hope this helps..

Best regards!!

Answer:

[tex]\displaystyle \boxed{\mathrm{3.95 \: kg }}[/tex]

Explanation:

[tex]\mathrm{force \: (N) = mass \: (kg) \times acceleration \: (m/s^2)}[/tex]

[tex]\mathrm{force = 30N}[/tex]

[tex]\mathrm{acceleration = 7.6 \: m/s^2 }[/tex]

[tex]\mathrm{Find \: the \: mass.}[/tex]

[tex]\mathrm{30 = m \times 7.6}[/tex]

[tex]\displaystyle \mathrm{m =\frac{30}{7.6} }[/tex]

[tex]\displaystyle \mathrm{m = 3.947... }[/tex]

Answer:

88 %

Explanation:

The rate of heat loss by a conducting material of thermal conductivity K, cross-sectional area,A and thickness d with a temperature gradient ΔT is given by

P = KAΔT/d

The total heat lost by the styrofoam wall is P₁ = K₁A₁ΔT₁/d₁ where K₁ =thermal conductivity of styrofoam wall 0.033 W/m-K, A₁ = area of styrofoam wall = 17 m², ΔT₁ = temperature gradient between inside and outside of the wall and d₁ = thickness of styrofoam wall = 0.20 m

The total heat lost by the glass window is P₂ = K₂A₂ΔT₂/d₂ where K₂ =thermal conductivity of glass window pane wall 0.96 W/m-K, A₂ = area of glass window pane = 0.15 m², ΔT₂ = temperature gradient between inside and outside of the window and d₂ = thickness of glass window pane = 7 mm = 0.007 m

The total heat lost is P = P₁ + P₂ = K₁A₁ΔT₁/d₁ + K₂A₂ΔT₂/d₂

Now, since the temperatures of both inside and outside of both window and wall are the same, ΔT₁ = ΔT₂ = ΔT

So, P = K₁A₁ΔT/d₁ + K₂A₂ΔT/d₂

Since P₂ = K₂A₂ΔT₂/d₂ = K₂A₂ΔT/d₂is the heat lost by the window, the fraction of the heat lost by the window from the total heat lost is

P₂/P = K₂A₂ΔT/d₂ ÷ (K₁A₁ΔT/d₁ + K₂A₂ΔT/d₂)

= 1/(K₁A₁ΔT/d₁÷K₂A₂ΔT/d₂ + 1)

= 1/(K₁A₁d₂÷K₂A₂d₁ + 1)

= 1/[(0.033 W/m-K × 17 m² × 0.007 m ÷ 0.96 W/m-K × 0.15 m² × 0.20 m) + 1]

= 1/(0.003927/0.0288 + 1)

= 1/(0.1364 + 1)

= 1/1.1364

= 0.88.

The percentage is thus P₂/P × 100 % = 0.88 × 100 % = 88 %

The percentage of heat lost by window of the total heat is 88 %

Answer:

W =1562.53 N

Explanation:

It is given that,

Radius of the aluminium ball, r = 24 cm = 0.24 m

The density of Aluminium, [tex]d=2698.4\ kg/m^3[/tex]

We need to find the thrust and the force. The mass of the liquid displaced is given by :

[tex]m=dV[/tex]

V is volume

Weight of the displaced liquid

W = mg

[tex]W=dVg[/tex]

So,

[tex]W=dg\times \dfrac{4}{3}\pi r^3\\\\W=2698.4\times 10\times \dfrac{4}{3}\times \pi \times (0.24)^3\\\\W=1562.53\ N[/tex]

So, the thrust and the force is 1562.53 N.

Explanation:

The kinetic energy of an object is given by :

[tex]E=\dfrac{1}{2}mv^2[/tex]

m is mass of the object

v is the speed of the object

It is clear from the above relation that the kinetic energy of the object is directly proportional to the product of mass and velocity.

The hypothesis can be :

If the speed of the object increased then its kinetic energy increase because kinetic energy is directly proportional to ist speed.

The kinetic energy of an object is given by :

m is mass of the object

v is the speed of the object

It is clear from the above relation that the kinetic energy of the object is directly proportional to the product of mass and velocity.

The hypothesis can be :

If the speed of the object increased then its kinetic energy increase because kinetic energy is directly proportional to its speed.