Which of these statements are correct about laws and theories?

Laws become theories after experimentation.
Theories become laws after experimentation.
Laws and theories are universal truths which cannot be verified.
Theories cannot become laws and laws cannot become theories.

Answer:

b

Explanation:

Answer:

the correct answer is D,  acceleration of gravity

Explanation:

In a projectile launch problem it is described by the expressions

        v = v₀ - g t

         v² = v₀² - 2 g y

        y = v₀ t - ½ g t²

By examining these equations we can see that acceleration is the magnitude that appears constant in all expressions.

 This acceleration is the acceleration of gravity with a value of g = 9.8 m/s² and directed towards the center of the Earth

therefore the correct answer is D

Answer:

40.2336

Explanation:

a.

The heat the engine extracts from its heat source in each cycle is 3.79 × 10⁴ J

The efficiency of the Carnot engine, ε = W/Q where W = work done per cycle = 2.5 × 10⁴ J and Q = heat extracted in each cycle.

Making Q subject of the formula, we have

Q = W/ε

Since ε = 66% = 0.66, we substitute the values of the variables into the equation for Q.

So, Q = W/ε

Q = 2.5 × 10⁴ J/0.66

Q = 3.79 × 10⁴ J

So, the heat the engine extracts from its heat source in each cycle is 3.79 × 10⁴ J

b.

The temperature of its heat source is 588.76 °C

Also, the efficiency of the Carnot engine, ε = 1 - T/T' where T = temperature of exhaust heat = 20° C = 273 + 20 = 293 K and T' = temperature of heat source.

Making T' subject of the formula, we have

T' = T/(1 - ε)

Since ε = 66 % = 0.66

Substituting the values of the variables into the equation, we have

T' = T/(1 - ε)

T' = 293 K/(1 - 0.66)

T = 293 K/0.34

T = 861.76 K

We convert this to Celsius.

T(K) = T(°C) + 273

T(°C) = T(K) - 273

T(°C) = 861.76 - 273

T(°C) = 588.76 °C

So, the temperature of its heat source is 588.76 °C

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The correct answer is option 3 i.e., 5.50 Kg and 120 N had lowest acceleration among all options given.

What connection exists between force and mass of acceleration?

Mass times acceleration, or F=m x a, equals force. This means that in order to move an object at the same speed as an object with smaller mass, a stronger force is required. Newton's Second Law of Motion is this.

Acceleration = Force / Mass

Given, as per question in all the 4 options Force = 120 N same for all

So as per formula if we assume Force is constant

Then, if mass is increased then acceleration will be lowest as both are inversely proportional.

1. Acceleration= 120 / 4.25 = 28.23 m/s²

2. Acceleration= 120 / 3.25 = 34.28 m/s²

3. Acceleration= 120 / 5.50 = 21.81 m/s²

4. Acceleration= 120 / 4.50 = 26.66 m/s²

Hence answer is option number 3.

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(i) The total force acting on the train is the driving force minus the total resistance to motion. The total resistance to motion is the sum of the resistances of the three trucks. Therefore, the total force acting on the train is:

F = 37,000 N - (1,200 kg + 900 kg + 600 kg) ₓ 9.8 m/s² = 37,000 N - 25,740 N = 11,260 N

The acceleration of the train is given by the formula:

a = F / (m1 + m2 + m3) = 11,260 N / (1,200 kg + 900 kg + 600 kg) = 0.3 m/s²

Therefore, the acceleration of the train is 0.3 m/s².

(ii) The forces acting on truck Z are the driving force, the force in the coupling between trucks Y and Z, and the resistance to motion of truck Z. The diagram showing all the forces acting on truck Z in the line of its motion is:

Driving force ≥ Truck Z ≤ Force in coupling Y and Z ≤ Resistance to motion of truck Z

(iii) With the driving force removed and brakes applied, the total resistance to motion is the sum of the resistances of the three trucks and the additional resistance due to the brakes. Therefore, the total resistance to motion is:

R = (1,200 kg + 900 kg + 600 kg) ₓ 9.8 m/s²+ 11,000 N = 25,740 N + 11,000 N = 36,740 N

The total force acting on the train is the total resistance to motion. Therefore, the acceleration of the train is:

a = F / (m1 + m2 + m3) = 0 / (1,200 kg + 900 kg + 600 kg) = 0 m/s²

Therefore, the new acceleration of the train is 0 m/s².

(iv) When the brakes are applied to the engine, the force in the coupling between trucks Y and Z is equal to the resistance to motion of truck Z. Therefore, the force in the coupling between trucks Y and Z is:

F = 600 kg ² 9.8 m/s² + 11,000 N = 5,880 N + 11,000 N = 16,880 N

The force in the coupling between trucks Y and Z is a tension.

When the brakes are applied to truck Z, the force in the coupling between trucks Y and Z is equal to the resistance to motion of truck Z plus the resistance to motion of the engine and the trucks in front of truck Y. Therefore, the force in the coupling between trucks Y and Z is:

F = (600 kg + 900 kg + 1,200 kg) ₓ9.8 m/s² + 11,000 N = 17,640 N + 11,000 N = 28,640 N

The force in the coupling between trucks Y and Z is a thrust.

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Answer:

Distance of 400m.

Explanation:

Use your kinematics equation to solve for distance (we can use kinematics b/c acceleration is constant).

d = (initial velocity x time) + 1/2 at^2

d = (20 x 10) + 1/2 (4) (10)^2

d = 200 + 200

d = 400 m

According to the question the largest force constant of the spring that will be needed to meet the design criteria is -65937.5 N/m.

Force is an influence that causes a change in an object’s state of motion, either by causing it to move, speed up, slow down, or change direction. Force can also act on an object to cause it to deform or change shape. Force is a vector quantity, meaning it has both magnitude, or size, and direction associated with it. Examples of forces include gravitational force, electrical force, magnetic force, and friction force. Force is measured in newtons (N) and is usually expressed as a vector quantity using symbols such as F = ma, where F is the magnitude of the force, m is the mass of the object, and a is the acceleration of the object.

The equation for the total work done by the friction force is given by:

W = Fd = 515 N * 5.0 m = 2575 J

The equation for the total work done by the spring force is given by:

W = Fd = kx^2/2

Where k is the spring constant and x is the compression distance.

We can then use the conservation of energy equation to solve for k:

2575 J = (kx^2/2) + (1350 N * 5.0 m)

We can then rearrange the equation to solve for k:

k = (2575 J - 67500 J) / (0.25 m^2)

k = -65937.5 N/m

Therefore, the largest force constant of the spring that will be needed to meet the design criteria is -65937.5 N/m.

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Please i have asked a.question please help.me

Explanation:

Please i have asked a question in math please help me

This question is incomplete, the complete question is;

A 13 kg box rests on the flat surface. The coefficient of static friction and coefficient of kinetic friction is μ_s = 0.450 and μ_k = 0.380 respectively.

Let's say you got tired and you are now pushing with a force of 36 N. Find the acceleration of the box.

Answer: the acceleration of the box is 0.9548 m/s²    {backward}

Explanation:

Given that;

mass m = 13 kg

pushing the box with a force of 36 N

the acceleration of the box = ?

ones the box starts moving, kinetic frictional force starts acting.

so

f_k = μ_k × m × g

we substitute

f_k = 0.380 × 13 × 9.8

f_k = 48.412 N

force needed to keep it in motion is 48.412 N

so

Acceleration = Net Force / mass

Acceleration = (48.412 N - 36 N) / 13

Acceleration = 12.412 / 13

Acceleration = 0.9548 m/s²    {backward}

Therefore, the acceleration of the box is 0.9548 m/s²   {backward}

Answer:

The kinetic energy of the car is \(2.0\cdot 10^5 J\)

Explanation:

Answer:

20000

Explanation:

Speed = Wavelength x Wave Frequency. In this equation, wavelength is measured in meters and frequency is measured in hertz (Hz), or number of waves per second. Therefore, wave speed is given in meters per second, which is the SI unit for speed.

Answer:

20 seconds

360 meters

Explanation:

On a distance-time graph:

Therefore:

Convert Bus A's given speed of 54 km/h into m/s by dividing by 3.6:

\(\implies \sf 54\; km/h=\dfrac{54}{3.6}=15\:m/s\)

Therefore:

So the y-intercept is (0, 60) and the gradient is 15.

Substitute this information into the slope-intercept form of a linear equation to create an equation representing the motion of Bus A:

\(\boxed{y=15x+60}\)

Convert Bus B's given speed of 36 km/h into m/s by dividing by 3.6:

\(\implies \sf 36\; km/h=\dfrac{36}{3.6}=10\:m/s\)

Therefore:

So the y-intercept is (0, 160) and the gradient is 10.

Substitute this information into the slope-intercept form of a linear equation to create an equation representing the motion of Bus B:

\(\boxed{y=10x+160}\)

To find the time when Bus A is at the same position as Bus B, substitute Bus A's equation into Bus B's equation and solve for x:

\(\implies 15x+60=10x+160\)

\(\implies 15x+60-10x=10x+160-10x\)

\(\implies 5x+60=160\)

\(\implies 5x+60-60=160-60\)

\(\implies 5x=100\)

\(\implies \dfrac{5x}{5}=\dfrac{100}{5}\)

\(\implies x=20\)

Therefore, the two buses are at the same position 20 seconds after they start moving.

To find their position at this point, substitute x = 20 into one of the equations and solve for y:

\(\implies y=10(20)+160\)

\(\implies y=200+160\)

\(\implies y=360\)

Therefore, the two buses are at the same position at 360 m from the origin.

Bus A overtakes Bus B 20 seconds after they start moving and at 360 m from the origin.

Answer:

To determine the height to which the ball rises before it reaches its peak, we need to know the initial velocity of the ball and the acceleration due to gravity. Let's assume the initial velocity of the ball is v and the acceleration due to gravity is g.

The time it takes for the ball to reach its peak is one-half the total hang-time, or 1/2 * 6.25 s = 3.125 s.

The height to which the ball rises can be calculated using the formula:

height = v * t - (1/2) * g * t^2

Substituting in the values we know, we get:

height = v * 3.125 s - (1/2) * g * (3.125 s)^2

To solve for the height, we need to know the value of v and g. Without more information, it is not possible to determine the height to which the ball rises before it reaches its peak.

Explanation:

Answer:

Approximately \(47.9\; {\rm m}\) (assuming that \(g = 9.81\; {\rm m\cdot s^{-2}}\) and that air resistance on the baseball is negligible.)

Explanation:

If the air resistance on the baseball is negligible, the baseball will reach maximum height at exactly \((1/2)\) the time it is in the air. In this example, that will be \(t = (6.25\; {\rm s}) / (2) = 3.125\; {\rm s}\).

When the baseball is at maximum height, the velocity of the baseball will be \(0\). Let \(v_{f}\) denote the velocity of the baseball after a period of \(t\). After \(t = 3.125\; {\rm s}\), the baseball would reach maximum height with a velocity of \(v_{f} = 0\; {\rm m\cdot s^{-1}}\).

Since air resistance is negligible, the acceleration on the baseball will be constantly \(a = (-g) = (-9.81\; {\rm m\cdot s^{-2}})\).

Let \(v_{i}\) denote the initial velocity of this baseball. The SUVAT equation \(v_{f} = v_{i} + a\, t\) relates these quantities. Rearrange this equation and solve for initial velocity \(v_{i}\):

\(\begin{aligned}v_{i} &= v_{f} - a\, t \\ &= (0\; {\rm m\cdot s^{-1}}) - (-9.81\; {\rm m\cdot s^{-2}})\, (3.125\; {\rm s}) \\ &\approx 30.656\; {\rm m\cdot s^{-1}}\end{aligned}\).

The displacement of an object is the change in the position. Let \(x\) denote the displacement of the baseball when its velocity changed from \(v_{i} = 0\; {\rm m\cdot s^{-1}}\) (at starting point) to \(v_{t} \approx 30.656\; {\rm m\cdot s^{-1}}\) (at max height) in \(t = 3.125\; {\rm s}\). Apply the equation \(x = (1/2)\, (v_{i} + v_{t}) \, t\) to find the displacement of this baseball:

\(\begin{aligned}x &= \frac{1}{2}\, (v_{i} + v_{t})\, t \\ &\approx \frac{1}{2}\, (0\; {\rm m\cdot s^{-1}} + 30.565\; {\rm m\cdot s^{-1}})\, (3.125\; {\rm s}) \\ &\approx 47.9\; {\rm m}\end{aligned}\).

In other words, the position of the baseball changed by approximately \(47.9\; {\rm m}\) from the starting point to the position where the baseball reached maximum height. Hence, the maximum height of this baseball would be approximately \(47.9\; {\rm m}\!\).

Distance = (speed) x (time)

Car A: Distance = (8 m/s) x (43 s)  =  344 meters

Car B: Distance = (7 m/s) x (50 s)  =  350 meters

350 meters is a longer distance than 344 meters.

Car-B traveled a longer distance than Car-A did.

Answer:

\(\boxed {\boxed {\sf Car \ B : 350 \ meters }}\)

Explanation:

Distance is equal to the product of speed and time.

\(d=s*t\)

1. Car A

Car A has a speed of 8 meters per second and travels for 43 seconds.

\(s= 8 \ m/s \\t= 43 \ s\)

Substitute the values into the formula.

\(d= 8 \ m/s *43 \ s\)

Multiply and note that the seconds will cancel out.

\(d= 8 \ m*43= 344 \ m\)

2. Car B

Car B has a speed of 7 meters per second and travels for 50 seconds.

\(s= 7 \ m/s \\t= 50 \ s\)

Substitute the values in and multiply.

\(d= 7 \ m/s * 50 \ s\)

\(d= 7 \ m * 50 = 350 \ m\)

350 meters is a longer distance than 344 meters, so Car B traveled the longer distance.

Answer:

Approximately \(2.2\; {\rm m\cdot s^{-2}}\).

Explanation:

Acceleration is the rate at which velocity changes.

In this example, velocity has changed from \(v_{0} = 0\; {\rm m\cdot s^{-1}}\) to \(v_{1} = 27\; {\rm m\cdot s^{-1}}\). The total change in velocity is:

\(\begin{aligned}\Delta v &= v_{1} - v_{0} \\ &= 27\; {\rm m\cdot s^{-1}} - 0\; {\rm m\cdot s^{-1}} \\ &= 27\; {\rm m\cdot s^{-1}} \end{aligned}\).

This change happened over a period of \(\Delta t = 6.00\; {\rm s}\). Therefore:

\(\begin{aligned} & (\text{avg. acceleration}) \\ =\; & (\text{avg. rate of change in velocity}) \\ =\; & \frac{(\text{change in velocity})}{(\text{time required})}\\ =\; & \frac{\Delta v}{\Delta t} \\ \approx\; & \frac{27\; {\rm m\cdot s^{-1}}}{6.00\; {\rm s}} \\ \approx \; & 2.2\; {\rm m\cdot s^{-2}} \end{aligned}\).

There are 14025 x10^6 grains of sand in the sand box when it is full when there was present on average 55 grains in the box initially.

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Answer: Answers are below.

Explanation: The box to the left is a footwall, the middle box is the fault plane, and the box to the right is a hanging wall. Blocks that lie above a fault plane are called a hanging wall and blocks that lie below a fault plane are called a footwall.

Let me know if this is right! :)

To determine the magnetic force on a straight wire carrying a current in a uniform magnetic field, we can use the formula for the magnetic force:

F = I * L * B * sin(θ)

where:

F is the magnetic force,

I is the current in the wire,

L is the length of the wire,

B is the magnitude of the magnetic field, and

θ is the angle between the wire and the magnetic field.

In this case, the values are:

I = 30 A (current in the wire)

L = 2.0 m (length of the wire)

B = 55 mT = 0.055 T (magnitude of the magnetic field)

θ = 20° (angle between the wire and the magnetic field)

Substituting the values into the formula:

F = 30 A * 2.0 m * 0.055 T * sin(20°)

Calculating sin(20°):

F = 30 A * 2.0 m * 0.055 T * 0.3420

F ≈ 1.5714 N

Therefore, the magnetic force on the 2.0-meter length of wire carrying a current of 30 A in a region with a uniform magnetic field of magnitude 55 mT and at an angle of 20° away from the wire is approximately 1.5714 N.

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Answer:

The potential effects of mobile phone radiation on the biosystem, including the human body, have been a topic of research and debate for many years. Mobile phones emit non-ionizing radiation, which is different from ionizing radiation (such as X-rays) that is known to cause cellular damage and increase the risk of cancer. However, there is still concern about the effects of prolonged exposure to mobile phone radiation, especially on the brain and other sensitive organs.

Studies have shown that the radiation emitted by mobile phones can cause a slight increase in temperature in the brain and other tissues near the ear. This increase in temperature can potentially cause damage to cells and tissues, although the amount of radiation emitted by mobile phones is generally considered to be too low to cause significant harm.

There is also some evidence to suggest that mobile phone radiation can affect sleep patterns, as the radiation emitted by mobile phones can interfere with the body's natural circadian rhythm. This can potentially lead to sleep disturbances and other health problems.

Other potential effects of mobile phone radiation on the biosystem include changes in blood pressure, heart rate, and brain activity. Some studies have also suggested that mobile phone radiation may affect fertility in men by reducing sperm motility and increasing DNA damage.

While there is still much debate about the potential effects of mobile phone radiation on the biosystem, most experts agree that the risk of harm is generally low. However, it is still recommended that people take precautions to limit their exposure to mobile phone radiation, such as using hands-free devices or texting instead of making phone calls.

Explanation:

Answer:

As stated by the National Cancer Institute, "there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans. The only consistently recognized biological effect of radiofrequency radiation in humans is heating."

Explanation:

good afternoon

Answer: 550 cm

Explanation:

Original equation: 1/f= 1/do + 1/di.

F=50.0 cm, and do=55.0.

Since we don't have di, we'll have to subtract do to the other side, making the equation: 1/f - 1/do= 1/di.

Doing the math, 1/f - 1/do is 0.0018181818

Then to get di by itself, you multiply both sides by di. Then you divide by 0.0018181818 to get di by itself. You then get: di= 1/0.0018181818

At that point, you just divide 1 by 0.0018181818, which will give you 550 cm

There could be simpler way, but that is just what I did to get the answer. Answer was right on Acellus

When an object transported from earth to the moon, its mass remains same but weight becomes 1/6th that on earth..

In physics, mass is a quantitative measurement of inertia, a basic characteristic of all matter.

It essentially refers to a body of matter's resistance to changing its speed or location in response to the application of a force. The change caused by an applied force is smaller the more mass a body has.

The amount of a body's weight indicates how much gravity is pulling on it. Weight is calculated using the method w = mg. Since weight is a force, it has the same SI unit as a force, which is the Newton (N).

So, mass of an object is intrinsic property of the object - it remains same in earth and in moon. But weight is the amount of gravitational  attraction force. Moon has nearly 1/6th gravitational attraction field. So, the weight of the object on moon will be 1/6th that on earth.

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Answer:

natural convection

............

Answer:

D 30 minutes per day, 5 days a week

Answer: Mass= 13.6 kg

Explanation:

F = m * a

34 = m (2.5)

m = 34 / 2.5

m = 13.6 kg

Inertia is the ability of the body to remain in the state or in uniform motion unless some external force acts on the body.

The inertia of the body is direly proportional to the mass of the body.

Thus, the greater the mass of the body greater is its inertia.

Three types of inertia:

In the state of rest, the inertia of the body resists the cause of motion. This inertia is known as resting inertia.

In the state of uniform motion, the inertia resists the cause of changing of motion. This inertia is known as motion inertia.

Some external force is applied to the body to change the direction of the motion of the body, the inertia that opposes this change in direction is known as directional inertia.

Answer:

0.610m/s^2

Explanation:

Acceleration is defined as the ΔV/ΔT. In this case, the change in velocity is 1.43-0.32=1.11 m/s. The change in time is 1.82 seconds. Plugging in what we know, it will result in an acceleration of 0.610 m/s^2.