a child pulls on a string that is attached to a car. if the child does 80.2 J of work while pulling the car 25.0 m, with what force is the child pulling?

Answer: 760 cW/microgram

2 significant figures

Explanation: solution attached:

Answer:

760 [tex]\frac{cW}{micrograms}[/tex]

Explanation:

You have to know that:

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

So:

[tex]x=\frac{c*b}{a}[/tex]

In this case, you have [tex]\frac{760 GW}{1 kg}[/tex]

In this case, the rule of three is applied as follows: if 1 gigawatt [GW] = 100000000000 centiwatt [cW], 7.600 GW how many cW are they?

[tex]\frac{7.600 GW}{kg} *\frac{100000000000 cW}{1 GW} *\frac{1 kg}{1000000000 micrograms}=760 \frac{cW}{micrograms}[/tex]

Answer:

A. 1.11[mL/g]

Explanation:

We have to remember the expression to calculate the density, which says it's the relationship between mass and volume.

We can calculate the different densities for each of the samples.

density1 = m/V = 200/180 = 1.11[mL/g]

density2 = m/V = 300/270 = 1.11[mL/g]

density3 = m/V = 400/270 = 1.11[mL/g]

According to the initial data, we can determine that the density corresponds to 1.11 [mL/g]

Answer:

the answer is helium you already know that because im in college on my way to the military next week bless me

Explanation:

Answer:

the electron.

Explanation:

the atom has 3 types of particles: protons, neutrons, and electrons. protons have a positive charge, neutrons have a neutral charge, and they are both located in the nucleus. the electron is negatively charged, and it's located in the electron cloud, outside the nucleus.

Answer:

D

Explanation:

the answer is d because gravitational force is what allows them to rotate

hope this was helpful

Answer:

Original length = 2.97 m

Explanation:

Let the original length of the pendulum be 'L' m

Given:

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

Original time period of the pendulum (T) = 3.45 s

Now, the length is shortened by 1.0 m. So, the new length is 1 m less than the original length.

New length of the pendulum is, [tex]L_1=L-1[/tex]

New time period of the pendulum is, [tex]T_1=2.81\ s[/tex]

We know that, the time period of a simple pendulum of length 'L' is given as:

[tex]T=2\pi\sqrt{\frac{L}{g}}[/tex]-------------- (1)

So, for the new length, the time period is given as:

[tex]T_1=2\pi\sqrt{\frac{L_1}{g}}[/tex]------------ (2)

Squaring both the equations and then dividing them, we get:

[tex]\dfrac{T^2}{T_1^2}=\dfrac{(2\pi)^2\frac{L}{g}}{(2\pi)^2\frac{L_1}{g}}\\\\\\\dfrac{T^2}{T_1^2}=\dfrac{L}{L_1}\\\\\\L=\dfrac{T^2}{T_1^2}\times L_1[/tex]

Now, plug in the given values and calculate 'L'. This gives,

[tex]L=\frac{3.45^2}{2.81^2}\times (L-1)\\\\L=1.507L-1.507\\\\L-1.507L=-1.507\\\\-0.507L=-1.507\\\\L=\frac{-1.507}{-0.507}=2.97\ m[/tex]

Therefore, the original length of the simple pendulum is 2.97 m

The period of a simple pendulum can be calculated with the formula T = 2π√(L/g). When the length of the pendulum is shortened by 1.0m, the period becomes 2.81 seconds. By solving a system of equations related to the period and the length of the pendulum, we can get the original length and the acceleration.

The subject matter relates to physics, specifically kinematics, and the topic is the period of a simple pendulum. The formula to calculate the period of a simple pendulum is T = 2π√(L/g), where T is the period, L is the length of the pendulum, and g is the acceleration due to gravity. We know that when the length of the pendulum was shortened by 1.0m, its period became 2.81 seconds. We can plug these values into our formula and solve for the original length (L).

To find the original length, we first let L0 be the original length and L1 be the shortened length. Therefore, L1 = L0 - 1m. Now we have two equations, T0 = 2π√(L0/g) and T1 = 2π√(L1/g). Plug in the known values and solve the system of equations, you can get the original length and the acceleration. Note, that the typical value for acceleration due to gravity on Earth is g = 9.8 m/s².

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Answer:

100Kg.m/s

Explanation:

From the question, we obtained the following information:

M= Mass = 25kg

V = Velocity = 4m/s

Momentum =?

Momentum = MV = 25x4= 100Kg.m/s

Answer:

net force

Explanation:

The net force is the vector sum of all the forces that act upon an object. That is to say, the net force is the sum of all the forces, taking into account the fact that a force is a vector and two forces of equal magnitude and opposite direction will cancel each other out.

Answer:

mass

Explanation:

The gravitational force exerted on an object is called its weight. Weight can change based on the strength of the gravitational pull where the object is located. The weight is calculated by multiplying the object's mass by the gravitational acceleration.

The gravitational force exerted on an object is referred to as the object's Weight. This should not be confused with Mass, which is a measure of the amount of matter in an object and remains constant regardless of an object's location. Weight, however, can change depending on the gravitational pull of the surroundings. For instance, an object would weigh less on the moon than on Earth due to the moon's weaker gravitational pull.

Calculating the weight of an object is done by multiplying the mass of the object by the gravitational acceleration (approximately 9.8 m/s^2 on Earth). The typical unit of weight in the International System of Units (SI) is the Newton (N).

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Answer:4.0*10^5 joules

Explanation:

y= 2.52 - 14.10x

Explanation:

Form a table as shown below

  x          y        x²        y²        xy

13        17     169       289       221

20       19     400      361         380

22       23     484      529        506

18        16      324      256        288

19        20     361       400        380

11         10      121         100        110

10        11        100       121         110

15        18      225       324        270

128     134     2184      2383   2265        sum

The formula for correlation is given by;

y=a + bx

a= ( ∑y)(∑x²) - (∑x)(∑xy) / n (∑x²)-(∑x)²

a=(134)(2184) - (128)(2265) / 8 (2184)-(128²)

a=292656 - 289920 / 17472-16384

a=2.515

b= n (∑xy) -(∑x)(∑y) / n (∑x²)-(∑x)²

b=8 (226) -(128)(134) / 8 (2184) - 128²

b=1808-17152 / 17472-16384

b= -14.10

The equation is thus;

y= a+bx

y= 2.52 - 14.10x

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Final answer:

To find Spearman's rank correlation coefficient for the given data, rank the values of X and Y, calculate the differences and squared differences of these ranks, and apply the Spearman's coefficient formula. A direct calculation cannot be provided without these intermediate steps. Spearman's correlation is appropriate for non-linear relationships.

Explanation:

To calculate Spearman's rank correlation coefficient between X and Y for the provided set of data, we must first rank the values of X and Y separately from lowest to highest and then compute the differences between the ranks for each pair of X and Y. After finding the squared differences of the ranks, we utilize the formula for Spearman's rank correlation coefficient:

rs = 1 - ( (6 ∑ d2 ) / (n(n2 - 1)) )

where d is the difference between the ranks of each pair and n is the number of pairs of scores. However, with the given information and without the ordered ranks and the differences of ranks, we cannot proceed to calculate the coefficient directly. We also need to note that if the variables show a curvilinear relationship or no clear linear relationship, Spearman's correlation would be a better measure of correlation than Pearson's.

The student should rank the values, compute the differences, square those differences, and substitute into the above formula to find Spearman's rank correlation coefficient.

Answer: 2200J

Explanation:

M = 44kg

V = 10m/s

K.E =?

K.E = 1/2MV2 = 1/2 x 44 x (10)^2

K.E = 22 x 100

K.E = 2200J

Answer

B

Explanation:

i took that same test i'm pretty sure it's B

Nuclear decay forms new B) A radioactive particle

There are many types of nuclear decay:-

Alpha decay

beta decay

gamma decay

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Answer:

Vc = 60[v], I = 5[amp]; Vx = 20 [v]

Explanation:

To solve this problem we have to perform a mesh analysis, we identify the meshes of the circuit we can appreciate that they are two meshes, in each we suppose a direction of current and we make a sum of voltages equal to zero for each mesh. Remember that ohm's voltage by law is defined as the product of current by resistance.

In the attached image, you can see the direction of the supposed current in each of the meshes, from this analysis we obtain two equations with the I & i2 currents

Mesh 1

[tex]60+(6*i)-(6*i_{2})+8*i = 0\\60+(14*i)-(6*i_{2})=0[/tex]

Mesh 2

[tex](12*i_{2}) + (6*i_{2})-(6*i)=0\\(18*i_{2})-(6*i)=0\\(18*i_{2})=(6*i)\\i = 3*i_{2}[/tex]

Now we can find the current i, replacing in the first equation.

[tex]60+(14*3*i_{2})-(6*i_{2})=0\\-60= (42-6)*i_{2}\\i_{2} = - 1.66666[amp]\\[/tex]

and

i = 3* (-1.66666)

i = -5 [amp]

Note: The negative sign means that the current has the opposite direction to the supposed originally.

Therefore:

Vc = 60 [v]

io = 5 [amp]

Now to determine the current in the resistance of 6 [ohms], we must know the current that passes through it, by means of a summation of currents in any of its nodes.

This current is equal to:

-1.66 = I + (-5)

I = 3.33[amp]

And using the ohm's law we can find the voltage

Vx = (3.33*6)

Vx = 20 [V]

Explanation:

According to gas equation  P₁V₁/T₁ = P₂V₂/T₂

Where P₁ is the initial pressure , V₁ is the initial volume and T₁ is the initial temperature

P₂ is the final pressure , V₂ is the final volume and T₂ is the final temperature

Thus P₁ = 15 atmosphere  , V₁ = 12 liters and T₁ = 273 + 20 = 293 K

P₂ = ? , V₂ = 8.5 liters , T₂ = 273 + 35 = 308 K

From gas equation P₂ = P₁V₁T₂/T₁V₂ = 15 x 12 x 308/ 293 x 8.5

= 22.3 atmosphere .

If the volume is doubled

The gas equation will be P₁V₁ = P₂V₂ ;  because temperature is constant

Here V₂ = 2 V₁  therefore  pressure P₂ = P₁/2 = 22.3/2 = 11.1 atmosphere

Answer:

Circuit breakers

Explanation:

This is an automatic device designed for stopping the flow of current in an electric circuit as a safety measure.

Ground Fault Circuit Interrupters (GFCIs), circuit breakers, and fuses are designed to interrupt the current flow of electricity when unsafe conditions arise.

Ground Fault Circuit Interrupters (GFCIs), circuit breakers, and fuses are all designed to interrupt the current flow of electricity when unsafe conditions arise. GFCIs are specifically designed to detect ground faults, which occur when current leaks to the ground, and they quickly shut off the power to prevent electric shocks. Circuit breakers monitor the current flowing through a circuit and trip when the current exceeds a certain threshold, protecting against overloads and short circuits. Fuses also protect against overloads and short circuits by melting and interrupting the current flow.

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Answer:

They have not erupted for a long time

Explanation:

They have not erupted for a long time is correct because dormant volcanoes are volcanoes that are active and have erupted once in the last 10,000 years. Because they are active, they will erupt again in the future.

Answer:

The net force on the frog is  zero Newton.

Explanation:

Balance forces are 2 forces that is acting in opposite directions on an object, and equal in size. Anytime there is a balanced force on an object, the object stays still or continues moving continues to move at the same speed and in the same direction

In Figure , the forces exerted on the frog is equal in magnitude and opposite in direction.

Hence

The force , F1 = 200 N and F2 =  -200 N since it is acting in opposite direction

Now the net force =F1 + F2 =  200 - 200 = 0

1) The ratio between the number of turns of the two electromagnets is 2

2) The ratio between the number of paper clips picked up is 2.2

Explanation:

1)

An electromagnet is a device consisting of a coil of wire wrapped around an iron core. Such a device is able to create a magnetic field, and in this problem this is used to attract and pick up the paper clips.

In this problem, we have two electromagnets:

- The first one has 50 turns

- The second one has 25 turns

Therefoore, the ratio of the number of turns of the 50-turn electromagnet to the number of turns of the 25-coil electromagnet is:

[tex]\frac{N_1}{N_2}=\frac{50}{25}=2[/tex]

2)

The strength of the magnetic field produced by an electromagnet is directly proportional to the number of turns in the coil wrapped on the electromagnet:

[tex]B\propto N[/tex]

This means that the electromagnet with more turns will produce a stronger magnetic field, and therefore it will be able to pickup more paper clips.

In this problem, in fact:

- The electromagnet with 50 turns can pick up 13 paper clips

- The electromagnet with 25 turns picks up 6 paper clips

Therefore, the ratio of the number of paper clips picked up is:

[tex]\frac{p_1}{p_2}=\frac{13}{6}=2.2[/tex]

And we see that this ratio is approximately equal to the ratio of the number of turns, which is 2.

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Answer:

the answer ia A

Explanation:

The wavelength of the given data will be 30 cm since the unit of wavelength is meter or centimeter.

The distance between two successive troughs or crests is known as the wavelength. The peak of the wave is the highest point, while the trough is the lowest.

The wavelength is also defined as the distance between two locations in a wave that have the same oscillation phase.

The length of a wave is measured in its propagation direction. The wavelength is measured in meters, centimeters, nanometers, and other units since it is a distance measurement.

The relationship between the wave's wavelength, frequency, and speed is given as

[tex]\rm wavelength = \dfrac{speed of light} { frequency}[/tex]

Hence the wavelength of the given data will be 30 cm

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Answer:

weathering

Explanation:

A) Displacement after 6.0 s 43.2 m uphill.

B) Displacement after 9.0 s 43.2 m uphill.

Explanation:

A car moving upwards in a hill is [tex]12 ms^{-1}[/tex].

Its uniform backward acceleration is [tex]-1.6ms^{-2}[/tex]. (since backward acceleration is a negative acceleration, it is mentioned in negative)

We need to find the displacement of the car after some time.

Using the equation of the motion formula, we know can identify the displacement.

D=[tex]vt+\frac{1}{2} at^2[/tex].

a) Displacement after 6.0 seconds,

D = [tex]12(6.0)+\frac{1}{2}(-1.6)(6.0)^2[/tex].

=[tex]72+\frac{1}{2} (36)(-1.6).[/tex]

=[tex]72+\frac{1}{2}(-57.6).[/tex]

=72-28.8.

D=43.2 m.

b) Displacement after 9.0 seconds,

D= [tex]12(9.0)+\frac{1}{2}(-1.6)(9.0)^2[/tex].

=[tex]108+\frac{1}{2} (81)(-1.6).[/tex]

=[tex]108+\frac{1}{2}(-129.6).[/tex]

= 108-64.8.

D=43.2 m.

The car's displacement after 6.0 s is 14.4 m and after 9.0 s is 43.2 m.

To find the displacement of the car after a given time, we can use the equation:
Displacement (d) = Initial velocity (v) * time (t) + (1/2) * acceleration (a) * time^2

a. After 6.0 s:
Initial velocity (v) = 12 m/s
Acceleration (a) = -1.6 m/s^2 (negative because it's a backward acceleration)
Substituting the values into the equation:
d = (12 m/s) * (6.0 s) + (1/2) * (-1.6 m/s^2) * (6.0 s)^2 = 72 m - 57.6 m = 14.4 m

b. After 9.0 s:
Using the same equation and substituting the new time, we can calculate the displacement:
d = (12 m/s) * (9.0 s) + (1/2) * (-1.6 m/s^2) * (9.0 s)^2 = 108 m - 64.8 m = 43.2 m

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Final answer:

To find the final speed of the roller coaster at the second hill, we can use the conservation of energy equation. Substituting the given values into the equation, we find that the final speed of the roller coaster at the bottom of the first hill is approximately 14.14 m/s. Assuming negligible friction, this will be the speed of the roller coaster at the top of the second hill.

Explanation:

To find the final speed of the roller coaster at the second hill, we can use conservation of energy. At the top of the first hill, the roller coaster has gravitational potential energy which is converted into kinetic energy at the bottom of the first hill.

Using the conservation of energy equation: mgh = (1/2)mv², where m is the mass of the roller coaster, g is the acceleration due to gravity, h is the height of the hill, and v is the final velocity, we can solve for v. Plugging in the values, we have (150 kg)(9.8 m/s²)(50 m) = (1/2)(150 kg)v².

Solving this equation, we find that the final speed of the roller coaster at the bottom of the first hill is approximately 14.14 m/s. Since the work done by frictional forces is negligible, we can assume that the roller coaster will maintain this speed as it goes up the second hill.

Answer:

18 mV

Explanation:

The maximum emf is:

ε = N B A ω

where N is the number of turns in the coil,

B is the strength of the magnetic field,

A is the area of the coil,

and ω is the angular velocity.

The number of turns N is equal to the length of the wire divided by the circumference of the coil.

N = L / (2πr)

Area of the coil is:

A = πr²

The angular velocity in rad/s is:

ω = rpm × 2π / 60 s

Therefore:

ε = (L / (2πr)) B (πr²) (rpm × 2π / 60 s)

ε = L B r (rpm × π / 60 s)

Plugging in values:

ε = (1.6 m) (0.071 T) (0.032 m) (93 × π / 60 s)

ε = 0.018 Tm²/s

ε = 18 mV

To find the maximum emf for a rotating coil in a magnetic field, use Faraday's law. The given wire length, rotation speed, and magnetic field strength can be used to calculate the emf after determining the number of turns and the coil area. The calculation results in an approximate maximum emf of 18 mV.

To find the maximum emf induced in a rotating coil within a magnetic field, we can use Faraday's law of electromagnetic induction which states that the emf (ε) induced in a coil is directly proportional to the rate of change of magnetic flux through the coil. Mathematically, ε = NABωsin(ωt+φ), where N is the number of turns, A is the area of the coil, B is the magnetic field strength, ω is the angular velocity, and ωt+φ is the phase angle. In this scenario, the coil is rotating at 93 RPM (revolutions per minute), which we can convert to radians per second (rad/s) since 1 revolution is equal to 2π radians: 93 RPM * 2π rad/rev * 1 min/60 s = 9.735 rad/s. The area (A) of the coil with radius (r = 3.2 cm = 0.032 m) can be found using the formula for the area of a circle: A = πr².

As the wire length is 1.6 m, we need to calculate the number of turns (N) by dividing the length of the wire (L = 1.6 m) by the circumference of the coil (C = 2πr), yielding N = L/C. Finally, to find the peak or maximum emf, we consider that sin(ωt+φ) is 1 at maximum. Plugging in the values, we get the maximum emf:

N = 1.6 m / (2π * 0.032 m) ≈ 7.958 turns (approx. 8 turns since a coil cannot have a fraction of a turn).
A = π * (0.032 m)² ≈ 0.0032 m².
ε(max) ≈ 8 turns * 0.0032 m² * 9.735 rad/s * 7.1 x 10⁻² T.

Calculating this givesapproximately 18 mV as the maximum emf, which should be provided in millivolts (mV) and rounded to two significant figures according to the question, resulting in 18 mV.

The final speed of a body after 2.23 s with a positive acceleration of 2.64 m/s² is 12.988 m/s. With a negative acceleration of -2.64 m/s², the speed after 2.23 s is 1.212 m/s.

To find out the speed of a body after 2.23 s when it accelerates uniformly, we need to use the formula for calculating final velocity (v) which is:
v = u + at, where:

For the first scenario with an acceleration of 2.64 m/s², we have:

v = 7.1 m/s + (2.64 m/s² × 2.23 s) = 7.1 m/s + 5.888 m/s = 12.988 m/s.

For the second scenario with an acceleration of -2.64 m/s² (which indicates deceleration), we have:

v = 7.1 m/s + (-2.64 m/s² × 2.23 s) = 7.1 m/s - 5.888 m/s = 1.212 m/s.

Therefore, the final speed after 2.23 s with a positive acceleration of 2.64 m/s² is 12.988 m/s, and with a negative acceleration (deceleration) of -2.64 m/s², the final speed is 1.212 m/s.

Answer: D

Explanation:

The graph that represents an object increasing its position with a constant velocity is Graph B because a straight, diagonal line indicates the object is moving with a constant velocity, and a positive slope means it is increasing its position. Hence, option (D) is correct.

The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction. SI unit of velocity is meter/second.

Mathematically:

velocity = ( final position - initial position)/time interval

Hence,

Final position = initial position + velocity ×time interval

Hence, the x-t graph of a  object with constant velocity, is linear in nature with a positive slope. Hence, graph (B) is the correct option.

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