A weight lifter lifts a 1470N barbell above his head from the floor the a height of 2m. he holds the barbell there for 5 sec. how much work does he do?

Answer:

E = 75 J

Explanation:

First, we will calculate the total power consumed by the five lamps:

[tex]Total\ Power = P = (5)(Power\ of\ one\ lamp)\\P = (5)(3\ W)\\P = 15\ W[/tex]

Now, the energy supply can be calculated as follows:

[tex]E = Pt[/tex]

where,

E = Energy = ?

t = time = 5 s

Therefore,

E = (15 W)(5 s)

E = 75 J

Answer: a different one is a.b.c

Explanation: still for ape.x

The correct order to determine the age of the an object using carbon-14 is C, A, B. Thus, option D is correct.

The half-life time is defined as the time taken by the radioactive element to reduce one half of its initial value. It is denoted by t(1/2).

To measure the age of an object, a radioactive isotope called carbon-14 is used. The half-life of carbon-14 is 5,730 years. All the objects in the universe consumes carbon  in their lifetime and hence, carbon-14 is used to measure the age of the objects.

The process of determining the age of objects using carbon-14 is called Radiocarbon dating. All living organisms consume carbon in means of food and from atmosphere and when the plant and animals dies, the radioactive carbon atoms start decaying.

When it starts decaying, by using Carbon-14 the age of an object is calculated. The age is estimated by measuring the amount of carbon-14 present in the sample and comparing this carbon with the reference Carbon-14 isotope.

The amount of carbon in  preserved plants is identified by:

f(t) = 10e {₋ct}  

t = time in years when the plant dies( t= 0)

c = the amount of carbon-14 remaining in preserved plants.

The steps include to find the age of an object is :

1. Use the number of half-lives that have passed to determine the age of the object.

2. Use the half-life of carbon-14 to determine the number of half-lives that have passed.

3.Measure the ratio of parent nuclei to daughter nuclei.

Hence, from these steps the age of an object is determined. Therefore the correct solution is D) C, A, B.

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Answer:

150

Explanation:

P=F/A

10=15/A

10*15=15/A*15

150=A

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The following that describes an electric insulator are :

C. A material that has a high resistance and prevents charges from  moving freely.    

Thus, the correct answer is C.

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Answer:

Power = 4000watts

Energy = 22.22Joules

Explanation:

Power = I²R

I is the current

R is the resistance

t is the time

Given the following

I = 20Amps

R = 10ohms

t = 3miuntes = 180secs

Substitute

P = 20²*10

P = 400*10

P = 4000Watts

Hence the amount of power used is 4000Watts

Energy used = Power/time

Energy used= 4000/180

Energy used = 22.22Joules

Answer:

Explanation:

The center of gravity  will act at the middle point that is at 4.38 m from the end of the plank that is on boat . 16.35 x 9.8 N will act at this point .

The plank will turn around a point at 3.17 m from the end of plank that is on boat .

Suppose the weight required be W . It will be placed at the end of the plank that is on boat . The position of man is on the extreme end of the plank that is over water . So its distance from turning point will be 8.76 - 3.17 = 5.59 m .

Taking torque about turning point of all the forces like , weight of plank , weight of the person walking and force due to W

W   x 3.17 =  16.35 x ( 4.38 - 3.17 ) + 60.3 x ( 8.76 - 3.17 )

W   x 3.17 =  19.78  + 337.07 = 356.85

W = 112.57 kg .

Answer:

P = 9622.9 Pa = 9.62 KPa

Explanation:

First, we will calculate the mass of all three liquids:

m = ρV

where,

m = mass of liquid

ρ = density of liquid

V = Volume of liquid

FOR LIQUID 1:

m₁ = (2.8 x 10³ kg/m³)(2 x 10⁻³ m³) = 5.6 kg

m₂ = (1 x 10³ kg/m³)(1.5 x 10⁻³ m³) = 1.5 kg

m₃ = (0.6 x 10³ kg/m³)(1 x 10⁻³ m³) = 0.6 kg

The total mass will be:

m = m₁ + m₂+ m₃ = 5.6 kg + 1.5 kg + 0.6 kg

m = 7.7 kg

Hence, the weight of the liquids will be:

W = mg = (7.7 kg)(9.81 m/s²) = 75.54 N

Now, we calculate the base area:

A = πr² = π(0.05 m)²

A = 7.85 x 10⁻³ m²

Now the pressure will be given as:

[tex]P = \frac{F}{A}\\\\P = \frac{75.54\ N}{7.85\ x\ 10^{-3}\ m^2}[/tex]

P = 9622.9 Pa = 9.62 KPa

Answer:

(D) energy from one place to another

Answer:

I think it's A

Explanation:

It's definitely not B on edge

The correct option for the given question about Einstein's general

theory of relativity is Option A) Mars, Venus, Uranus, Neptune.

As a Conclusion, we can state that the planets who would cause curvature in space time from the least amount of curvature to the greatest will be in order Mars, Venus, Uranus, Neptune.

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Answer: C-  The intensity increases by a factor 9

Explanation: The intensity of a sound wave follows an inverse square law, that means that it is inversely proportional to the square of the distance: so  the new distance is the intensity will increase by a factor 9.

My sentence- I hope that helped!

Intensity of a sound wave decreases by a factor of 9, if the distance from the source is increased by a factor of 3. Hence option B is correct.

Intensity of Sound is inversely proportional to the square of the distance from the sound source. Since sound waves carry its energy though a two-dimensional or three-dimensional medium, the intensity of the sound wave decreases with increasing as second power of distance form the source.

Mathematically,

Intensity I ∝ 1/D²

If the distance from the source is increased by a factor of 3, Then

I ∝ 1/3² ∝ 1/9

Intensity ∝  1/9

Hence option B is correct.

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Answer:

40

Explanation:

Answer:

3,000 meters = 3 kilometers

Explanation:

Answer:

42.6083 mi/h

Explanation:

Given: A car travels 8km in 7 minutes.

To find: Find the speed of the car.

Formula: [tex]Speed = \frac{Distance}{Time}[/tex]

Solution: Since the formula for the speed of an object (which is the car) is speed = distance ÷ time, divide the distance (8km) by the time (7min)

Speed = 42.6083 miles per hour

Answer: If the magnification is positive, the image is upright compared to the object; if m is negative, the image is inverted compared to the object.

(I think, I was also stuck on this question for a bit)

The positive sign indicate about the image that

b) The image is on the same side of the mirror as the object.

d) The image is upright.

Magnification  is a quantification of comparing the size of the image with respect to the size of the object. It gives us information about the image in terms of how large or small is the image formed.

magnification   = height of image / height of object

since , height of object  is always positive as it is always kept upright hence , in order to make m positive ,  height of image  need to be positive

also magnification    = -(v/u )

v = image distance

u = object distance

u is always positive hence , in order to make m positive , v needs to be negative , which implies on the same side of the mirror as the object

correct option

b) The image is on the same side of the mirror as the object.

d) The image is upright.

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Answer:

Definimos momento como el producto entre la masa y la velocidad

P = m*v

(tener en cuenta que la velocidad es un vector, por lo que el momento también será un vector)

Sabemos que el peso de la paca de heno es 175N, y el peso es masa por aceleración gravitatoria, entonces.

Peso = m*9.8m/s^2 = 175N

m = (175N)/(9.8m/s^2) = 17.9 kg

Ahora debemos calcular la velocidad de la paca justo antes de tocar el suelo.

Sabemos que la velocidad horizontal será la misma que tenía el avión, que es:

Vx = 36m/s

Mientras que para la velocidad vertical, usamos la conservación de la energía:

E = U + K

Apenas se suelta la caja, esta tiene velocidad cero, entonces su energía cinética será cero y la caja solo tendrá energía potencial (Si bien la caja tiene velocidad horizontal en este punto, por la superposición lineal podemos separar el problema en un caso horizontal y en un caso vertical, y en el caso vertical no hay velocidad inicial)

Entonces al principio solo hay energía potencial:

U = m*g*h

donde:

m = masa

g = aceleración gravitatoria

h = altura  

Sabemos que la altura inicial es 60m, entonces la energía potencial es:

U = 175N*60m = 10,500 N

Cuando la paca esta próxima a golpear el suelo, la altura h tiende a cero, por lo que la energía potencial se hace cero, y en este punto solo tendremos energía cinética, entonces:

10,500N = (m/2)*v^2

De acá podemos despejar la velocidad vertical justo antes de golpear el suelo.

√(10,500N*(2/ 17.9 kg)) = 34.25 m/s

La velocidad vertical es 34.25 m/s

Entonces el vector velocidad se podrá escribir como:

V = (36 m/s, -34.25 m/s)

Donde el signo menos en la velocidad vertical es porque la velocidad vertical es hacia abajo.

Reemplazando esto en la ecuación del momento obtenemos:

P = 17.9kg*(36 m/s, -34.25 m/s)  

P = (644.4 N, -613.075 N)

We/Wm = ge/gm = 120N/1.2N

or

gm = ge/100 = 0.1 m/s^2

density = mass/volume = 3M/(4pir^3)

Re-arranging this equation, we get

M/r^2 = (4/3)×pi×(density)×r

From Newton's universal law of gravitation, the acceleration due to gravity on the moon gm is

gm = G(M/r^2) = G×(4/3)×pi×(density)×r

Solving for density, we get the expression

density = 3gm/(4×pi×G×r)

= 3(0.1)/(4×3.14×6.67×10^-11×2.74×10^6)

= 130.6 kg/m^3

Answer:

A. The shorter the distance the greater the force, so now the force would have increased because they haven't moved away from each other.

B. The force would decrease because they are now further apart.

C. the force wouldn't be as great as before but the force would still be high because they are not far apart from each other.

I hope this helps you( ◜‿◝ )♡

Answer:

The right answer is "1010 V/m".

Explanation:

The given values are:

Intensity,

[tex]I=1350 \ W/m^2[/tex]

[tex]c = 3.00\times 108 \ m/s[/tex]

[tex]\mu_0= 4\pi\times 10^{-7} \ T.m/A[/tex]

Now,

The electric field's maximum value will be:

=  [tex]\sqrt{2\times u\times c\times I}[/tex]

On substituting the values in the above formula, we get

=  [tex]\sqrt{2\times 4\times \pi\times 10^{-7}\times 3\times 10^8\times 1350}[/tex]

=  [tex]\sqrt{32400\times 3.14\times 10^{-7}\times 10^8}[/tex]

=  [tex]1010 \ V/m[/tex]

The maximum value of the electric field associated with this radiation is :

Given data :

Intensity ( I ) = 1350 W/m²

C = 3.00 * 10⁸ m/s

The maximum value of the electric field can be calculated using the equation below

[tex]E_{max} = \sqrt{2*u*c*I}[/tex]  ----- ( 1 )

where :  I = 1350 W/m²,  μ =  4π * 10⁻⁷,  c = 3.00 * 10⁸

Insert values into equation ( 1 )

∴ [tex]E_{max}[/tex] = 1010 V/m.

Hence we can conclude that the maximum value of the electric field is 1010 V/m .

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Answer:

a=vf - vi/t

vf=final velocity

vi= initial velocity

t=time period

Now The bicycle went from 3ms to 1ms...

1.. It decelerated

2... Since it went from 3 to 1... 1 is the final velocity while 3 is the initial Velocity

Applying the Formula

a= 1-3/2

= -2/2

a= -1ms-²

Option D

Answer: 0 m/s. that is your answer i hope this help sorry if i am wrong

Explanation:

What does the area under the curve on a velocity-versus-time graph represent? ... then slows down to travel the last 40 miles in three hours. ... 20. A bicyclist travels the first 700 m of a trip at an average speed of 8 m/s, travels the ... to complete the trip at an average speed, for the entire trip of 440 km/h. ... 125) v1= 0 m/s.

Answer:

The work done by you on the two cart system is 2 N-m

Explanation:

Work done is the product of force and displacement.

W = F * D

Substituting the given values we get -

W =

[tex]4 * (0.17+0.33)\\= 2[/tex]

The work done by you on the two cart system is 2 N-m

Answer:

n = 1.56 x 10¹⁷ electrons

Explanation:

First of all, we will calculate the current passing through wire:

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

where,

I = current = ?

q = charge = 9 mC = 0.009 C

t = time = 3.6 s

Therefore,

[tex]I = \frac{0.009\ C}{3.6\ s}\\\\I = 0.0025\ A = 2.5\ mA[/tex]

Now, for the same current in 10 s time the charge will be:

q = It = (0.0025 A)(10 s)

q = 0.025 C

Now, the number of electrons can be given as:

[tex]q = ne\\\\n = \frac{q}{e}\\\\[/tex]

where,

n = no. of electrons = ?

q = charge = 0.025 C

e = charge on single electron = 1.6 x 10⁻¹⁹ C

Therefore,

[tex]n = \frac{0.025\ C}{1.6\ x\ 10^{-19}\ C}[/tex]

n = 1.56 x 10¹⁷ electrons

Answer:

[tex]\boxed {\boxed {\sf 2.40 \ meters}}[/tex]

Explanation:

Work is the product of force and distance, so the formula is:

[tex]W= F \times d[/tex]

The work is 6.00 Joules, but

The force is 2.50 Newtons.

The known values are:

Substitute the values into the formula.

[tex]6.00 \ N*m= 2.50 \ N *d[/tex]

We are solving for distance, so we must isolate the variable, d. It is being multiplied by 2.50 Newtons and the inverse of multiplication is division. Divide both sides by 2.50 N.

[tex]\frac {6.00 \ N*m}{2.50 \ N}=\frac{2.50 \ N * d}{2.50 \ N}[/tex]

[tex]\frac {6.00 \ N*m}{2.50 \ N}=d[/tex]

The units of Newtons cancel out.

[tex]\frac {6.00 m}{2.50 }=d[/tex]

[tex]2.40 \ m =d[/tex]

The force was applied to the rock over a distance of 2.40 meters and choice C is correct.

Answer:

[tex]380697.33\ \text{N/m}[/tex]

[tex]0.138\ \text{m}[/tex]

Explanation:

m = Mass rocket = 1070 kg

v = Velocity of rocket = 3.75 m/s

a = Acceleration of rocket = 5g

g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]

The energy balance of the system is given by

[tex]\dfrac{1}{2}kx^2=\dfrac{1}{2}mv^2\\\Rightarrow kx=\dfrac{mv^2}{x}\\\Rightarrow kx=\dfrac{1070\times 3.75^2}{x}\\\Rightarrow kx=\dfrac{7250}{x}[/tex]

The force balance of the system is given by

[tex]ma=kx\\\Rightarrow m5g=\dfrac{7250}{x}\\\Rightarrow x=\dfrac{7250}{1070\times 5\times 9.81}\\\Rightarrow x=0.138\ \text{m}[/tex]

The distance the spring must be compressed is [tex]0.138\ \text{m}[/tex]

[tex]k=\dfrac{7250}{x^2}\\\Rightarrow k=\dfrac{7250}{0.138^2}\\\Rightarrow k=380697.33\ \text{N/m}[/tex]

The force constant of the spring is [tex]380697.33\ \text{N/m}[/tex].

False

Explanation:

Called an asteroid for many years, Ceres is so much bigger and so different from its rocky neighbors that scientists classified it as a dwarf planet in 2006. Even though Ceres comprises 25 percent of the asteroid belt's total mass, tiny Pluto is still 14 times more massive.

Answer: 5

Explanation: B is for sure 60°, c* cosB = 10*1/2 =5

Answer:

Option C and D only

Explanation:

Option A is incorrect  because refractive index of a material is the ratio of speed of light in vacuum to the speed of light in a any given medium

Option B is correct as the speed of light in vacuum is always greater than the speed of light in any given medium.

Option C is correct

Option D is incorrect

Option E is incorrect because the denser the medium the more is the refractive index. Water is denser than air, hence it should have more refractive index as compared to that of air.