A branch falls from a tree. How fast is the branch moving after 0.28 seconds?
A. 2.7 m/s
B. 1.3 m/s
C. 4.4 m/s
D. 3.1 m/s

Answer:

1.  1, 2, 4 all show some form of refraction as the bending of a light ray when passing from one media to another.

Explanation:

Number 4 is the most accurate as it also shows some light being reflected and the bending of the refracted light ray in the correct direction for going from a medium of low refractive index (air) into a higher refractive index material (crown glass)

Answer:

TRUE

FALSE

TRUE

TRUE

TRUE

TRUE

Explanation:

1. Most EM waves has the same speed. True

2. EM waves travel at the speed of 4x108 m/s. False

3. Electromagnetic waves are transverse waves consisting of changing electric fields and changing magnetic fields. True

4. Electromagnetic waves transfer energy through a vacuum. True

5. A wave is a disturbance that transfers energy. True

Answer:

The distance traveled before takeoff is 1720 m

Explanation:

a = + 3.2 m/s²

t = 32.8 s

Vᵢ = 0 m/s

d = ?

Now,

d = Vᵢ × t + 0.5 × a × t²

d = (0 m/s) × (32.8 s) + 0.5 × (3.20 m/s²) × (32.8 s)²

d = 1720 m

Thus, The distance traveled before takeoff is 1720 m

-TheUnknownScientist 72

Answer:

speed of sound, speed at which sound waves propagate through different materials. In particular, for dry air at a temperature of 0 °C (32 °F), the modern value for the speed of sound is 331.29 metres (1,086.9 feet) per second

Answer:

What is the average force of collision?

Explanation:

The velocity of the combined mass after impact is found by conservation of momentum

0.480(75) + 0.240(0) = (0.480 + 0.240)v

v = 50 m/s

An impulse results in a change of momentum

FΔt = mΔv

F = mΔv/Δt

for the pigeon

F = 0.240(50 - 0)/0.015

F = 800 N

for the falcon

F = 0.480(50 - 75)/0.015

F = -800 N

The final speed(v) of the Peregrine falcons and pigeon is 50 m/s

The objective of this question is to determine the final speed(v) of the Peregrine falcons and pigeon

From the information given:

According to the conservation of momentum, we can say that the totality of momentum before and after the collision is the same. As such;

[tex]\mathbf{m_fv_f = (m_f+m_p) v}[/tex]

[tex]\mathbf{480 g \times 75 m/s = (480 + 240) \ g \times v}[/tex]

[tex]\mathbf{v = \dfrac{480 g \times 75 m/s}{(480 + 240) \ g}}[/tex]

[tex]\mathbf{v = \dfrac{36000 \ m/s}{ 720}}[/tex]

v = 50 m/s

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Answer:

The 10% must come off the energy, not the velocity

Explanation:

Change in height h = 1.89 + 2.20 = 4.09 m

Potential energy = mgh = m(9.81)(4.09) = 40.1m J

Friction losses 40.1m(0.10) = 4.01m J

Kinetic energy at end 40.1m - 4.01m = 36.1m J

KE = ½mv²

v = √(2KE/m)

v = √(2(36.1m)/m = √72.2

v = 8.4983...

v = 8.50 m/s

Answer:

Explanation:

The work will equal the increase in potential energy.

PE = mgh

m = PE/gh = W/gh = 201/(9.81(3.85)) = 5.32 kg

Answer:

Explanation:

The work of the brakes will equal the initial kinetic energy of the car

Fd = ½mv²

F = mv²/2d

F = 2457(18²) / (2(62))

F = 6,419.903...

F = 6.4 kN

Answer:

Explanation:

Step 1 of 4

CONCEPT:

The mathematical expression for magnetic field B at center of a coil:

Here,  is the current in the coil, N is the number of turns of the coil, is the permeability of the free space and  is radius of the coil.

Rearrange above equation for current in the coil.

Answer:

B. . by consuming plants or other animals

Answer:

No

Explanation:

Changing momentum of any kind requires work. Work is a force acting over a distance. While holding the weights at arms length and spinning will create a force (centripetal), there is no radial distance change incurred. Releasing the weights will reduce the force to zero, still no work done and no change in angular momentum.

If he was holding the weights at arms length while spinning and he pull his hands to his chest, there now exists both the centripetal force and a distance in the direction of that force (inward radial) this work will result in an increase in angular velocity as moment of inertia has decreased with the work done.

No, the skater doesn't succeed in changing his angular velocity.

The final angular velocity of the skater is determined by applying the principle of conservation of angular momentum as shown below;

Li = Lf

[tex]Ii\omega _i = I_f \omega _f[/tex]

where;

When the skater holds the weight, the momnet of inertia of both arms is the same. Also when the skater drops the weight, the moment of inertia of both arms is still the same. Thus, at any instant, the moment of inertia of the two arms is the same.

To change the angular speed, the initial and final moment of inertia of the two arms must be different. Thus, the skater doesn't succeed in changing his angular velocity.

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Answer:

Explanation:

½(75)v² = ½(0.008)390²

        v² = (0.008)390²/75

        v² = 16.224

         v = 4.027...

         v = 4.0 m/s

Answer:

The angle of incidence = The angle of reflection

Explanation:

For instance, the formula is <i = <r which means if the surface is smooth then the reflacted anglw will be equal according to the normal (dotted 90°) line.

Upon being reflected backwards the angle of incidence is simply the same, except from the other side

Answer:

Diffrent

Explanation:

Electrical energy is electrical charges moving. When you play soccer kinetic energy is used. Kinetic energy is the movement of atoms, objects, and electrons.

Answer:

Explanation:

Conservation of momentum

Let's say the first child was headed north

North momentum

75(0) + 20(2) + 15(3sin45) = (75 + 20 + 15)vn

vn = 0.6529 m/s

East momentum

75(0) + 20(0) + 15(3cos45) = (75 + 20 + 15)ve

ve = 0.28927 m/s

θ = arctan(0.28927/0.6529)

θ = 23.896...

θ = 24° east of north

Answer:

M1 + M2 = 0   total momentum before explosion = momentum after explosion where M1 is the lighter fragment

M1 V1 + 7 M1 V2 = 0

V2 = -V1 / 7      

The lighter fragment will slide 7 times as far - 39.2 mm because it must have 7 times as much velocity - assuming the distance slid is proportional to the original velocity

Answer:

a vacuum tube is NOT a solid state component

Answer:

equal

Explanation:

Answer:

Explanation:

v = at

t = v/a

t = 20 m/s / 9.8 m/s²

t = 2.0408163...

t = 2.0 s

Answer:

14. scolded

15. supporter

16. i am not sure but I think it is removes

17. comfortable

18. outdated

19. drink

20. it can be fantastic or wealthy

Answer:

14. Reicon's parents admonished him for breaking their antique collection,

15. I am an advocate of anti-corruption movement in the country.

16. The hotel abolishes its rice-all-you-can policy to avoid wastage of food.

17. The country has a very tropical climate where it only has dry and wet

seasons similar to other countries in Southeast Asia

18. The obsolete books and other references in the library resulted to the

removal in the shelves and inventory.

19. Beverages, such as juices, milk, beers and sodas, have increased in,due to low supply and importation issues.

20. The luxurious life of my cousin in an exclusive subdivision in Ta makes me inspired to dream and work hard for me to escape this unp.

Answer:

23

Explanation:

3x-4

The formula of force is F = ma.

Force: This can be defined as the product of mass and acceleration. The S.I unit of force is Newton (N).  Force is a vector quantity

Types of force

⇒ The formula of force is

⇒ Where:

Hence, the formula of force is F = ma.

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Before looking at the formula, Lets understand what is force?

The formula used to find force is:

[tex] \sf \nrightarrow \: F=m×a[/tex]

Where,

Equation in words:- Force applied on an object is directly proportional or equal to the product of the mass of object and the acceleration of object.

Answer:

The speed of sound varies with the material in which the waves travel.

Explanation:

knowledge and research

It can be concluded as per the given table that the speed of sound varies with the material in which the waves travel. The correct option is A.

Speed is the pace at which an object's position changes in any direction. The distance travelled in relation to the time it took to travel that distance is how speed is defined. Since speed simply has a direction and no magnitude, it is a scalar quantity.

It has a dimension of time-distance. As a result, the fundamental unit of time and the basic unit of distance are combined to form the SI unit of speed. Thus, the metre per second (m/s) is the SI unit of speed.

According to the given table, it can be inferred that the material in which the waves travel affects the speed of sound.

Thus, the correct option is A.

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This question involves the concepts of dynamic pressure, volume flow rate, and flow speed.

It will take "5.1 hours" to fill the pool.

First, we will use the formula for the dynamic pressure to find out the flow speed of water:

[tex]P=\frac{1}{2}\rho v^2\\\\v=\sqrt{\frac{2P}{\rho}}[/tex]

where,

v = flow speed = ?

P = Dynamic Pressure = 55 psi[tex](\frac{6894.76\ Pa}{1\ psi})[/tex] = 379212 Pa

[tex]\rho[/tex] = density of water = 1000 kg/m³

Therefore,

[tex]v=\sqrt{\frac{2(379212\ Pa)}{1000\ kg/m^3}}[/tex]

v = 27.54 m/s

Now, we will use the formula for volume flow rate of water coming from the hose to find out the time taken by the pool to be filled:

[tex]\frac{V}{t} = Av\\\\t =\frac{V}{Av}[/tex]

where,

t = time to fill the pool = ?

A = Area of the mouth of hose = [tex]\frac{\pi (0.015875\ m)^2}{4}[/tex] = 1.98 x 10⁻⁴ m²

V = Volume of the pool = (Area of pool)(depth of pool) = A(1.524 m)

V = [tex][\frac{\pi (9.144\ m)^2}{4}][1.524\ m][/tex] = 100.1 m³

Therefore,

[tex]t = \frac{(100.1\ m^3)}{(1.98\ x\ 10^{-4}\ m^2)(27.54\ m/s)}\\\\[/tex]

t = 18353.5 s = 305.9 min = 5.1 hours

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Answer:

D. Tungsten

Explanation:

W - Wolfram

The distance r between the pions when the criteria are satisfied is 1.45 × 10⁻¹⁶ m

If we consider the potential energy (U) between the pions, then (U) can be expressed as:

[tex]\mathbf{U = \dfrac{kq^2}{r} ---- (1)}[/tex]

Given that at some instance, the potential energy becomes negligible compared to the final K.E.

As such the conservation of the total energy in the system can be given as:

Again, if we consider the ratio of the potential energy to the kinetic energy to be about 0.01, then:

[tex]\mathbf{\dfrac{U}{K}= 0.01} \\ \\ \mathbf{U = 0.01 K----(2)}[/tex]

∴

Equating both equations (1) and (2) together, we have:

[tex]\mathbf{\dfrac{kq^2}{r} = 0.01 K}[/tex]

[tex]\mathbf{\dfrac{kq^2}{r} = 0.01 \Bigg [ m_{o \pi}c^2 \Big [\dfrac{1}{\sqrt{1 - \dfrac{v_{\pi}^2}{c^2} }} \Big ] \Bigg] }[/tex]

[tex]\mathbf{r =\dfrac{kq^2}{ 0.01 \Bigg [ m_{o \pi}c^2 \Big [\dfrac{1}{\sqrt{1 - \dfrac{v_{\pi}^2}{c^2} }} \Big ] \Bigg] }}[/tex]

where:

Replacing their values in the  above equation, the distance (r) between the pions is calculated as:

[tex]\mathbf{r =\dfrac{(9\times 10^9 \ N.m^2/C^2) (1.6022 \times 10^{-19} \ C)^2}{ 0.01 \Bigg [ (2.5 \times 10^{-28\ kg } )\times (3\times 10^8 \ m/s)^2 \Big [\dfrac{1}{\sqrt{1 - \dfrac{(2.97 \times 10^8 \ m/s)^2}{(3 \times 10^8 \ m/s)^2} }} \Big ] \Bigg] }}[/tex]

distance (r) = 1.45 × 10⁻¹⁶ m

Therefore, we can conclude that the distance r between the pions when the criteria are satisfied is 1.45 × 10⁻¹⁶ m

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Explanation:

the speed of sound is affected by temperature and humidity

[tex] \large★·.·´¯`·.·★ {Answer}★·.·´¯`·.·★[/tex]

As we know that Kinetic Energy is the Energy that is possessed by a moving object. and if the object is at rest then it doesn't have velocity therefore there is no kinetic Energy.

In the numerical terms we can express it as : -

[tex]꧁  \:  \large \frak{Eternal \:  Being } \: ꧂[/tex]