A wrench is accidentally dropped at the top of an elevator shaft in a tall building. (a) How many meters does the wrench fall in 1.5s

Answer:

W = 41.45 Kcal

Explanation:

Given that,

The mass of a person, m = 75 kg

He climbs 248 steps to the top of the Cape Hatteras lighthouse, a total climb of 59 m.

We need to find how many calories does he or she burn.

Work done = Fd

d is displacement

⇒ W = 75 ×9.8 ×59

= 43365  J

Let the efficiency is 0.25.

[tex]W=\dfrac{43365}{0.25}\\\\=173460\ J\\\\\text{or}\\\\=41.45\ kcal[/tex]

So, 41.45 Kcal is burned by the person.

Answer:

Explanation:

The force engine exert on the car can be found by using the formula

[tex]f = \frac{w}{d} \\ [/tex]

w is the workdone

d is the distance

From the question we have

[tex]f = \frac{520}{260} = 2 \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

Explanation:

The momentum of an object can be found by using the formula

momentum = mass × velocity

From the question we have

momentum = 12 × 24

We have the final answer as

Hope this helps you

Answer:

The evidence that the universe is expanding comes with something called the red-shift of light. Light travels to Earth from other galaxies. As the light from that galaxy gets closer to Earth, the distance between Earth and the galaxy increases, which causes the wavelength of that light to get longer. Distant galaxies are getting further away hinting at a point of origin. The composition of all observed matter in this universe points at a common origin point for all matter in the universe.

The three crucial evidences that supported the Big Bang theory are the CMB or cosmic microwave background, the expanding universe, the abundance of elements in the universe.

Big Bang theory is one of the important theory scientists used in earliest to describe the origin of universe and the phenomenon of evolution.

Here,

2. The Big Bang theory described the origin of universe as an expansion from an atmosphere of high density and extreme temperature which lead to a huge explosion of matter known as the  'Big Bang' and thus creation of  the universe.

The three crucial evidences that supported the Big Bang theory are:

The CMB or cosmic microwave background, the expanding universe, the abundance of elements in the universe.

3.(a) Light spectra was an important factor that supported the Big Bang theory mainly by the phenomenon called Doppler shift. Doppler shift occurs when stars move away, they get shifted to longer wavelength. This phenomenon is called red-shift or Doppler's Red shift. This was applicable in the case of Big Bang theory such that the theory claimed that, as a result of explosion which is the Big Bang, the material particles move away. This was similar to the red shift.

(b) The motion of distant galaxies was an evidence of the expansion of universe and soo the Big Bang theory. It was explained in such a way that, as the galaxies move away from us, it shows the more expansion of universe and the time duration since the origin of universe.

(c) The composition of matter in the universe was an important evidence that supported the Big Bang theory. The composition of universe that there is high abundance of hydrogen and helium in the atmosphere was claimed by the Big Bang theory.

Hence,

The three crucial evidences that supported the Big Bang theory are the CMB or cosmic microwave background, the expanding universe, the abundance of elements in the universe.

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Answer:

77000 J

Explanation:

Formula for the heat energy is;

Q = m•c•Δt

We are given;

mass; m = 2 kg

Change in temperature; Δt = 110 - 10 = 100 °C

From online values, specific heat capacity of copper is; c = 385 J/kg.°C

Thus;

Q = 2 × 100 × 385

Q = 77000 J

Answer:

heat = 20 Kcal

Explanation:

Answer:

Explanation:

The weaker force is pulling to direction East(450 newton)

the net force is (500-450=50 newton) and will move toward west ( in 500 newton direction)

Answer:

E = 4.7 x [tex]10^{-19}[/tex] Joules

Explanation:

Solution:

The wavelength of a particular color of violet light = 417 nm

What is the energy = ?

In order to calculate energy, we will use the following formula:

E = hf

where, f = frequency = 1/wavelength = c/λ

where c = speed of light = 299 792 458 m / s or 3 x [tex]10^{8}[/tex] m/s

where h = Plank's constant = 6.62x [tex]10^{-34}[/tex] [tex]m^{2}[/tex] kg / s

So,

λ = 417 nm

1 nm = [tex]10^{-9}[/tex] m

so,

λ = 417 x [tex]10^{-9}[/tex] m

Now, just plug in the values to calculate the energy of this wavelength of light.

E = hc/λ

E = ( 6.62x [tex]10^{-34}[/tex] ) (299 792 458) / (417 x [tex]10^{-9}[/tex] )

E = 0.047 x[tex]10^{-17}[/tex]

E = 4.7 x [tex]10^{-19}[/tex] Joules

Answer:

i think b

Explanation:

Answer:

50m

Explanation:im just smart thank me later

The range is 80 meter and  the stone is 4.04 second in air​.

When a particle is hurled obliquely near the surface of the earth, it travels along a curved path while accelerating continuously in the direction of the planet's center (we assume the particle stays close to the surface of the globe). Such a particle's motion is known as projectile motion, and its route is referred to as a projectile.

Given that: maximum height obtained by the projectile; H = 20 m.

Let initial velocity = u

For maximum range:

H = u²/4g

u = √(4gH) = 28 m/s

and  the range  of the projectile = u²/g = 4H = 4 ×20 m = 80 m.

Total time of flight = √2· u/g = √2 ×28/9.8 = 4.04 second.

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Answer:

Its C

Explanation:

My teacher did it for me and it was right.

Answer:

air resistance and gravity.

Explanation:

When the ball is falling down at terminal velocity, the velocity is constant.

This means that the net force acting on the ball will be zero (there is no acceleration)

In this situation, there are only two forces that can act on the ball.

The gravitational force, that pulls the ball down.

The air resistance which opposes to the movement of the ball and increases in magnitude as the velocity of the ball increases.

Then there is a point where the velocity of the ball is such that the air resistance is equal in magnitude to the acceleration, and then the net force becomes zero.

Then the two forces that need to be included in this diagram are the air resistance and gravity.

Answer:

 Q = 4 Q₀

Explanation:

This is an exercise on capacitors, where the capacitance is

         C =  [tex]\epsilon_{o} \ \frac{A}{d}[/tex]

if we apply the given conditions

         C = \epsilon_{o} \    \frac{2A}{0.5d}

         C = 4 \epsilon_{o} \    \frac{A}{d}

let's call the capacitance Co with the initial values

         C₀ = \epsilon_{o} \    \frac{A}{d}

         C = 4 C₀

The charge on each plate of a capacitor is

           Q = C ΔV

If the potential difference is maintained, the new charge is

       Q = 4 C₀ ΔV

let's call

        Q₀ = C₀ ΔV

we substitute

        Q = 4 Q₀

Answer:

The average power delivered by the elevator motor during this period is 6.686 kW.

Explanation:

Given;

mass of the elevator, m = 636 kg

initial speed of the elevator, u = 0

time of motion, t = 4.5 s

final speed of the elevator, v = 2.05 m/s

The upward force of the elevator is calculated as;

F = m(a + g)

where;

m is mass of the elevator

a is the constant acceleration of the elevator

g is acceleration due to gravity = 9.8 m/s²

[tex]a = \frac{v-u}{t} \\\\a = \frac{2.05 -0}{4.5} \\\\a = 0.456 \ m/s^2[/tex]

F = (636)(0.456 + 9.8)

F = (636)(10.256)

F = 6522.816 N

The average power delivered by the elevator is calculated as;

[tex]P_{avg} = \frac{1}{2} (Fv)\\\\P_{avg} = \frac{1}{2} (6522.816 \ \times \ 2.05)\\\\P_{avg} = 6685.89 \ W\\\\P_{avg} = 6.68589 \ kW\\\\P_{avg} = 6.686 \ k W[/tex]

Therefore, the average power delivered by the elevator motor during this period is 6.686 kW.

Answer:

v = 24.49[m/s]    

Explanation:

We must remember that kinetic energy can be calculated by means of a mathematical expression, which relates kinetic energy to mass and velocity

[tex]E_{kin}=\frac{1}{2}*m*v^{2} \\[/tex]

where:

Ekin = kinetic energy = 12000 [J]

m = mass = 40 [kg]

v = velocity [m/s]

[tex]12000=\frac{1}{2} *40*v^{2}\\24000=40*v^{2}\\600=v^{2}\\v=\sqrt{600}\\v=24.49[m/s][/tex]

Answer:

3, it's the igneous rock, sedimentary rock, and metamorphic rock i believe

Explanation:

Answer:

igneous, sedimentary, and metamorphic.

Explanation:

Answer:

I believe it to be option A

Explanation:

Answer:

A faster because teens what to drink it more when. they see there parents do it

Research indicates that teenagers have a faster tendency compared to adults in these case.

Good behavior in pre-teens and teenagers starts with positive communication and warm relationships. This lays the foundation for guiding your child’s behavior in a positive way.

Here are some practical tips for putting this positive approach into action.

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Answer: 162500000

Explanation:

given data:

wire diameter = 1.8mm

wire length = 15cm

current = 260mA.

electron charge e = [tex]1.6*10^{-19} C[/tex]

Solution:

[tex]I = \frac{q}{t}[/tex]

where:

[tex]I = current\\\\q = charge\\\\t = time \\\\q=It\\\\q= 260mt[/tex]

[tex]q=ne\\\\n = \frac{q}{e} \\\\n= \frac{260*10^{-3} t}{1.6*10^{-19} } \\\\n= 162500000t\\\\\frac{n}{t} = 162500000[/tex]

number of electrons per seconds would be 162500000

Answer:

i think its D

Explanation:

Answer:

yes

Explanation:

Answer:

y e p  

Explanation:

Answer:

fixed pulley: A pulley system in which the pulley is attached to a fixed point and the rope is attached to the object. ... movable pulley: A pulley system in which the pulley is attached to the object; one end of the rope is attached to a fixed point and the other end of the rope is free.

Explanation:

Answer:

4. 10.0 m/s²

Explanation:

I) if initial velocity is 'v₀', the final velocity is 'v', the accelaration is 'a', the distance is 'L' and elapsed time if 't', then:

[tex]1. \ a=\frac{v-v_0}{t};[/tex]

[tex]2. \ L=\frac{at^2}{2}.[/tex]

II) using these two equations after substitution v₀=0; v=30 and L=45:

[tex]\left \{{{45 =\frac{at^2}{2}} \atop {a=\frac{30-0}{t} }} \right.[/tex]

[tex]\left \{ {{at^2=90} \atop {at=30}} \right. \ <=> \ \left \{ {{a=10} \atop {t=3}} \right.[/tex] [tex]=> \ a=10\frac{m}{s^2}[/tex]

Explanation:

u = Initial velocity = 20m/s

v = Final velocity = 0m/s

a = Acceleration = -5m/s²

We wish to find s, the displacement of the car.

Using Kinematics, we have v² = u² + 2as.

Therefore (0)² = (20)² + 2(-5)s, and s = 40m.

Answer:

4:1

Explanation:

Given that the initial speed of the first car, u = 2v while the initial speed of the second car, u = v. To find the distance travelled, we are going to apply one of the equations of motion. The equation chosen is

v² = u² - 2as, where

s = the distance needed

a = acceleration due to gravity

u = initial velocity which is v & 2v

v = final velocity which is 0

For the first car with initial velocity, 2v, on substituting into the equation, we have

v² = u² - 2as(1)

0 = 4v - 2as(1)

4v = 2as(1)

2v = as(1), making s(1) subject of formula we have

s(1) = 2v/a

Taking the second car, we have u = v

v² = u² - 2as(2)

0 = v - 2as(2)

v = 2as(2), making s(2) subject of formula, we have

s(2) = v/2a

Not, ratio of s1 : s2 =

2v/a : v/2a

s1/s2 = 2v/a ÷ v/2a

s1/s2 = 2v/a * 2a/v

s1/s2 = 4av/av

s1/s2 = 4/1

Therefore, the ratio of the first car to the second car is 4:1

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Answer:

Nuclear Fusion reactions power the Sun and other stars. In a fusion reaction, two light nuclei merge to form a single heavier nucleus. The process releases energy because the total mass of the resulting single nucleus is less than the mass of the two original nuclei.

Explanation:

The sun's energy comes in the form of a nuclear reaction due to the Two nuclei joining to form a larger nucleus. Thus option A is correct.

A nuclear fusion is a reaction in which 2 or more atomic nuclei combine to form one or more atomic nuclei and is manifested by the release or the absorber of energy.

This is due to the differeces in the nuclear binding energy due to the force of nuclei before and after the reaction. The process releases energy as single declines less than the mass of the original nuclei.

Find out more information about the nuclear reaction.

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Answer:

27.91ohms

Explanation:

From the question we are given the following

Voltage across the inductor VL = 120V

Current in the inductor I = 4.3A

Required

Inductive reactance XL

Using two formula

VL =IXL

XL = VL/I

XL = 120/4.3

XL = 27.91ohms

Hence the inductive reactance is 27.91ohms

Answer:

5×10¯⁴ m².

Explanation:

From the question given above, the following data were obtained:

Pressure (P) = 200 N/m²

Weight = Force (F) = 0.1 N

Area (A) =?

Pressure, force and area are related by the following equation:

Pressure (P) = Force (F) / Area (A)

P = F / A

With the above formula, we can obtain the area of the coin as follow:

Pressure (P) = 200 N/m²

Weight = Force (F) = 0.1 N

Area (A) =?

P = F / A

200 = 0.1 / A

Cross multiply

200 × A = 0.1

Divide both side by 200

A = 0.1 / 200

A = 5×10¯⁴ m²

Thus, the area of the coin is 5×10¯⁴ m².

Answer:

y = 160t - 16t²

Explanation:

Using y = ut -1/2gt² where y = height of heavy rock above the ground, u = initial launch velocity of rock = 160 ft/s, g = acceleration due to gravity = 32 ft/s² and t = time.

So, substituting the values of the variables into y, we have

y = (160 ft/s)t -1/2 × 32 ft/s² × t²

y = (160 ft/s)t - (16 ft/s²)t²

y = 160t - 16t²

So, the height function is y = 160t - 16t²