Marie curie investigation method

Explanation:

A. is chemically identical to heroin.

Answer:

electric force

Explanation:

its a contact and noncontact force

Answer:

Explanation:

18 kW = 18000 J /s

60% of 18kW = 10800 J/s

Latent heat of evaporation of water

= 2260 x 10³ J / kg

kg of water being evaporated per second

= 10800 / 2260 x 10³ kg /s

= 4.7787 x 10⁻³ kg / s

= 4.78 gm / s .

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 2000 × 8.3

We have the final answer as

Hope this helps you

Answer:

Burning coal and boiling water are both chemical changes. Burning coal is a chemical change, and boiling water is a physical change. Burning coal is a physical change, and boiling water is a chemical change.

Explanation:

The minimum mass required to be placed on the 0.00 cm mark of the meter stick to maintain equilibrium is 0.120 kg.

To maintain equilibrium, the torques acting on the meter stick must balance each other. The torque is given by the formula:

τ = r * F * sin(θ)

where τ is the torque, r is the distance from the pivot point to the point where the force is applied, F is the force applied, and θ is the angle between the force vector and the lever arm.

In this case, the meter stick is in equilibrium when the torques on both sides of the pivot point cancel each other out. The torque due to the weight of the meter stick itself is acting at the center of mass of the meter stick, which is at the 50.0 cm mark.

Let's denote the mass to be placed on the 0.00 cm mark as M. The torque due to the weight of M can be calculated as:

τ_M = r_M * F_M * sin(θ)

where r_M is the distance from the pivot point to the 0.00 cm mark (which is 30.0 cm), F_M is the weight of M, and θ is the angle between the weight vector and the lever arm.

Since the system is in equilibrium, the torques on both sides of the pivot point must be equal:

τ_M = τ_stick

r_M * F_M * sin(θ) = r_stick * F_stick * sin(θ)

Substituting the given values:

30.0 cm * F_M = 20.0 cm * (0.0400 kg * 9.8 m/s^2)

Solving for F_M:

F_M = (20.0 cm / 30.0 cm) * (0.0400 kg * 9.8 m/s^2)

F_M = 0.0264 kg * 9.8 m/s^2

F_M = 0.25872 N

Finally, we can convert the force into mass using the formula:

F = m * g

0.25872 N = M * 9.8 m/s^2

M = 0.0264 kg

Therefore, the minimum mass required to be placed on the 0.00 cm mark of the meter stick to maintain equilibrium is 0.120 kg.

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If the trend changed toward traditional (pre-World War II) families, the women’s rights are employment in manufacturing sector.

The war between two countries to take over each other's kingdom using weapons to kill each other.

Before the world war, the army needs armor, weapons, guns and tanks. Their manufacturing is only possible with many workers to work for long hours. If the men are not enough, then women are given opportunities to work with them.

Thus, the women’s rights are employment in manufacturing sector when trend changed traditional families.

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Answer:

Depends on position

Explanation:

Rest:

A body is said to be at rest, if it does not change its position with respect to its surroundings.

Motion:

A body is said to be in motion, if it changes its position with respect to its surroundings.

The state of rest and motion is relative

Answer:

Approximately \(31\%\) assuming that \(g = 9.81\; {\rm N \cdot kg^{-1}}\).

Explanation:

Consider an object of mass \(m\) in a uniform gravitational field of strength \(g\). If the height of that object increased by \(\Delta h\), the gravitational potential energy of that object would increase by \(m\, g\, \Delta h\).

In this question, the mass of the rocket is given to be \(m = 0.55\; {\rm kg}\). Assume that \(g = 9.81\; {\rm N \cdot kg^{-1}}\). The rocket has gained a height of \(\Delta h = 23\; {\rm m}\). Thus, the gravitational potential energy of this rocket would have increased by:

\(\begin{aligned} m\, g\, \Delta h &= 0.55\; {\rm kg} \times 9.81\; {\rm N \cdot kg^{-1}} \times 23\; {\rm m} \\ &\approx 124.1\; {\rm J} \end{aligned}\).

In other words, the useful energy output from the combustion of the rocket fuel was approximately \(124.1\; {\rm J}\).

The energy input to this rocket was given to be \(400.0\; {\rm J}\). Thus, the efficiency of the energy conversion would be:

\(\begin{aligned} \text{efficiency} &= \frac{(\text{useful energy out}\text{put})}{(\text{energy in}\text{put})} \times 100\% \\ &\approx \frac{124.1\; {\rm J}}{400.0\; {\rm J}} \times 100\% \\ &\approx 31\%\end{aligned}\).

The rock's altitude y at time t, thrown with initial velocity v, is given by

\(y=74\,\mathrm m+vt-\dfrac12gt^2\)

where \(g=9.80\frac{\rm m}{\mathrm s^2}\) is the acceleration due to gravity.

After t = 2.7 s, the rock reaches the water (0 altitude), so

\(0=74\,\mathrm m+v(2.7\,\mathrm s)-\dfrac12g(2.7\,\mathrm s)^2\)

\(\implies v=-\dfrac{74\,\mathrm m-\frac g2(2.7\,\mathrm s)^2}{2.7\,\mathrm s}\approx-14.177\dfrac{\rm m}{\rm s}\)

so the rock was thrown with a velocity with magnitude 14 m/s and downward direction.

Its velocity at time t is \(v-gt\) (with no horizontal component), so that at the moment it hits the water, its velocity is

\(v-g(2.7\,\mathrm s)\approx-40.637\dfrac{\rm m}{\rm s}\)

That is, its final velocity has an approximate magnitude of 41 m/s, also directed downward.

Option A) 3.9 km is the correct answer. the magnitude of Rhea's displacement vector is approximately 3.92 km.

In order to find out the magnitude of Rhea's displacement vector, we have to add up all of the displacement vectors.

Then we can use the Pythagorean theorem to calculate the magnitude of the resultant vector.

Since Rhea is first driving north for 2.4 km and then west for 3.1 km, we can represent her displacement vectors as follows: Δx = 0 km and Δy = 2.4 km for the first vector, and Δx = -3.1 km and Δy = 0 km for the second vector.

We can then add these vectors together by adding their components: Δx = 0 km + (-3.1 km) = -3.1 km and Δy = 2.4 km + 0 km = 2.4 km.

This gives us a resultant vector of -3.1 km east and 2.4 km north.

Using the Pythagorean theorem, we can find the magnitude of this vector: \(\sqrt{(\(-3.1 km)^{2} + (2.4 km)^{2} ) } = \sqrt{(9.61 + 5.76) km^{2} } = \sqrt{15.37 km^{2} } \approx 3.92 km.\)

Therefore, the magnitude of Rhea's displacement vector is approximately 3.92 km.

Therefore, option A) 3.9 km is the correct answer.

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Answer: 6.4 times.

Explanation:

First, remember the definition of work as:

W = F*d

where W is work, F is force and d is distance.

The work applied when using the machine is:

W = 10N*14m = 140J

The work that you would apply if you did not use the machine is:

W' = 180N*5m = 900J.

The ratio W'/W is = 900J/140J = 6.4

This means that the machine has made 6.4 times the work easier. (you needed 6.4 times less work to do the task

The change in the reservoir, the system or device, and the surroundings are added to determine the overall entropy change. The reservoir's entropy change is. Since entropy is a function of state and we are contemplating a complete cycle (return to initial state), the device's entropy change is zero.

For finite variations at constant T, entropy changes (S) are calculated using the relation G=ΔH - TΔS.

The generation, consumption, conversion, and exchange of thermal energy across physical systems is the focus of the thermal engineering field of study known as heat transfer. Different heat transmission techniques, including thermal conduction, thermal convection, thermal radiation, and energy transfer by phase changes, are categorized.

Conduction is the process through which heat is transported from an object's hotter end to its colder end. Heat naturally transfers from a hotter body to a colder body.

For instance, heat is transferred from the hotplate of an electric stove to the bottom of a saucepan that comes into touch with it.

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Answer:

Earth's magnetic field (and the surface magnetic field) is approximately a magnetic dipole, with the magnetic field S pole near the Earth's geographic north pole (see Magnetic North Pole) and the other magnetic field N pole near the Earth's geographic south pole (see Magnetic South Pole). This makes the compass usable for navigation. The cause of the field can be explained by dynamo theory. A magnetic field extends infinitely, though it weakens with distance from its source. The Earth's magnetic field, also called the geomagnetic field, which effectively extends several tens of thousands of kilometres into space, forms the Earth's magnetosphere. A paleomagnetic study of Australian red dacite and pillow basalt has estimated the magnetic field to be at least 3.5 billion years old

One of the main uses of this device is to examine a beam of charged particles

The cathode ray tube is a device used to determine the charge flowing in a gas. When an electric field is set up with the help of metal electrodes, the cathode ray tends to bend towards the positive electrode.

Since the cathode ray bends towards the electrodes, it implies that it has a charge and the electrodes present help us determine the charge of the beam of charged particles and thus examine the beam of charged particles.

So, one of the main uses of this device is to examine a beam of charged particles.

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Answer:

B

Explanation:

Answer:

16.66

Explanation:

Heya!!

For calculate aceleration, lets applicate formula:

                                                   \(\boxed{a=\frac{V-V_o}{t} }\)

                                                   Δ   Being   Δ

                                          V = Final Velocity = 5 m/s

                                         Vo = Initial Velocity = 2 m/s

                                          a = Aceleration = ? m/s²

                                                   t = Time = 7 s

⇒ Let's replace according the formula:

\(\boxed{a=\frac{5\ m/s - 2 \ m/s}{7\ s} }\)

⇒ Resolving

\(\boxed{ a=0,428\ m/s^{2}}\)

Result:

The aceleration of the object is 0,428 m/s²

Good Luck!!

Answer:

Ksasdasd

Explanation:

The  molecule of hydrogen peroxide contains four atoms.

The chemical equation for the reaction between oxygen and hydrogen to form hydrogen peroxide is:

O2 + 2H2 → 2H2O2

This equation shows that one molecule of oxygen (O2) reacts with two molecules of hydrogen (H2) to produce two molecules of hydrogen peroxide (H2O2).

We are given that one liter of oxygen (O2) combines with one liter of hydrogen (H2) to produce one liter of hydrogen peroxide (H2O2). Since one mole of any gas at standard temperature and pressure (STP) occupies 22.4 liters, we can assume that one mole of oxygen (O2) reacts with one mole of hydrogen (H2) to produce one mole of hydrogen peroxide (H2O2) at STP.

Using Avogadro's number (6.022 x 10^23), we can calculate the number of molecules of each substance in one mole:

Oxygen (O2): 1 mole = 6.022 x 10^23 molecules

Hydrogen (H2): 1 mole = 6.022 x 10^23 molecules

Hydrogen peroxide (H2O2): 1 mole = 6.022 x 10^23 molecules

From the balanced chemical equation, we know that two molecules of hydrogen peroxide (H2O2) are produced for every one molecule of oxygen (O2) that reacts. Therefore, the number of molecules of hydrogen peroxide (H2O2) produced is equal to the number of molecules of oxygen (O2) that react.

Since we are given that one liter of oxygen (O2) reacts with one liter of hydrogen (H2) to produce one liter of hydrogen peroxide (H2O2), we can say that the volumes of the gases are proportional to their number of molecules. Therefore, the number of molecules of hydrogen peroxide (H2O2) produced is also equal to the number of molecules of hydrogen (H2) that react.

So, we can start with one mole of hydrogen (H2) and use the balanced chemical equation to find the number of moles of hydrogen peroxide (H2O2) produced:

1 mole H2 → 2 moles H2O2

Since one molecule of hydrogen peroxide (H2O2) contains two hydrogen atoms and two oxygen atoms, we can find the total number of atoms in a molecule of hydrogen peroxide:

2 hydrogen atoms + 2 oxygen atoms = 4 atoms

Therefore, a molecule of hydrogen peroxide contains four atoms.

In summary:

The chemical equation for the reaction between oxygen and hydrogen to form hydrogen peroxide is: O2 + 2H2 → 2H2O2

Since the number of molecules of hydrogen peroxide (H2O2) produced is equal to the number of molecules of hydrogen (H2) that react, we can find the number of atoms in a molecule of hydrogen peroxide by considering the atoms in a molecule of hydrogen. Therefore, a molecule of hydrogen peroxide contains four atoms (two hydrogen atoms and two oxygen atoms).

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Answer:

The student should hold his umbrella at an angle facing south-west.

Answer:

HIV attacks a specific type of immune system cell in the body. It's known as the CD4 helper cell or T cell. When HIV destroys this cell, it becomes harder for the body to fight off other infections.

Explanation:

A projectile is an object thrown into the air and subject only to gravity and, if applicable, air resistance. The time taken by disc C to reach its maximum height is approximately 1.53 seconds, and its maximum height above the ground is around 11.48 meters. The time from when disc C was thrown upwards until ball B hits the disc is roughly 1.29 seconds.

3.1 Explanation of the term projectile:

A projectile refers to an object that is launched or thrown into the air and is subject only to the forces of gravity and air resistance (if applicable). The motion of a projectile can be analyzed independently of its mass, shape, or any other physical property. The key characteristic of a projectile is that it follows a curved path known as a trajectory.

When a projectile is launched, it moves along a parabolic trajectory due to the combination of its initial velocity and the force of gravity acting vertically downward. The horizontal motion of a projectile remains constant and unaffected by gravity, while the vertical motion is influenced by the acceleration due to gravity.

The path of a projectile can be described mathematically by considering its initial velocity, angle of projection, and the acceleration due to gravity. Projectile motion finds applications in various fields, such as sports, engineering, and physics, where objects are launched or thrown.

3.2.1 Time taken by disc C to reach its maximum height:

To determine the time taken by disc C to reach its maximum height, we can use the kinematic equation for vertical motion. The equation is:

vf = vi + at

Where:

vf = final velocity (which is zero at the maximum height)

vi = initial velocity

a = acceleration (in this case, acceleration due to gravity, -9.8 m/s²)

t = time

Since the disc is thrown vertically upwards, its initial velocity is 15 m/s. We want to find the time it takes for the disc to reach its maximum height, so we'll use the equation and solve for time (t):

0 = 15 + (-9.8)t

Rearranging the equation, we get:

9.8t = 15

t = 15 / 9.8

Calculating this, we find:

t ≈ 1.53 seconds

Therefore, it takes approximately 1.53 seconds for disc C to reach its maximum height.

3.2.2 Maximum height above the ground reached by disc C:

To determine the maximum height reached by disc C, we can use another kinematic equation for vertical motion:

vf² = vi² + 2ad

Where:

vf = final velocity (which is zero at the maximum height)

vi = initial velocity

a = acceleration (in this case, acceleration due to gravity, -9.8 m/s²)

d = displacement (maximum height)

Since we know the initial velocity (vi) and acceleration (a), we can solve for the displacement (d), which represents the maximum height:

0² = 15² + 2(-9.8)d

Rearranging the equation, we get:

0 = 225 - 19.6d

19.6d = 225

d = 225 / 19.6

Calculating this, we find:

d ≈ 11.48 meters

Therefore, the disc C reaches a maximum height of approximately 11.48 meters above the ground.

Calculating the time from the moment that disc C was thrown upwards until the time ball B hits the disc:

To find the time it takes for ball B to hit disc C, we need to calculate the time it takes for both objects to reach the same height.

Since disc C was thrown upwards from the edge of the roof and ball B was shot vertically upwards from the foot of the building, we need to consider the additional height of the building (30 meters).

The time it takes for disc C to reach the ground is the same as the time it takes for ball B to reach a height of 30 meters above the ground.

Using the kinematic equation for vertical motion, we can calculate the time for ball B:

d = vit + 0.5at²

Where:

d = displacement (30 meters)

vi = initial velocity (40 m/s)

a = acceleration (acceleration due to gravity, -9.8 m/s²)

t = time

30 = 40t + 0.5(-9.8)t²

Rearranging the equation, we get:

4.9t² + 40t - 30 = 0

Solving this quadratic equation, we find:

t ≈ 1.29 seconds or t ≈ -5.82 seconds

Since time cannot be negative in this context, we discard the negative solution.

Therefore, it takes approximately 1.29 seconds from the moment that disc C was thrown upwards until ball B hits the disc.

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The pendulum will be moving at approximately 0.754 m/s when it passes through the lowest point of its swing.

To determine the speed of the pendulum when it passes through the lowest point of its swing, we can use the principle of conservation of mechanical energy.

At the highest point (2.9 cm above the resting position), the pendulum has gravitational potential energy. As it swings down, this potential energy is converted into kinetic energy, given by the equation:

Potential Energy (PE) = Kinetic Energy (KE)

The highest point's potential energy is given by:

PE = mgh

Where:

m = pendulum mass (4.0 kg).

g = acceleration due to gravity (9.8 m/s^2)

h = height above the resting position (2.9 cm = 0.029 m)

Substituting the values, we have:

PE = 4.0 kg * 9.8 m/s^2 * 0.029 m = 1.1356 J

Since energy is conserved, this potential energy will be completely converted into kinetic energy at the lowest point. Thus, the kinetic energy is also 1.1356 J:

KE = 1.1356 J

The following equation gives the kinetic energy:

KE = (1/2)mv^2

Where:

m = pendulum mass (4.0 kg).

v = velocity of the pendulum at the lowest point

Rearranging the equation to solve for v:

v^2 = (2KE) / m

v^2 = (2 * 1.1356 J) / 4.0 kg

v^2 = 0.5678 m^2/s^2

Taking the square root of both sides results in the following:

v ≈ 0.754 m/s

Therefore, the pendulum will be moving at approximately 0.754 m/s when it passes through the lowest point of its swing.

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Answer:

Specific heat (Cp) water (at 15°C/60°F): 4.187 kJ/kgK = 1.001 Btu(IT)/(lbm °F) or kcal/(kg K)

Answer:

C

Explanation:

I think it's C, because at that point, you are going fastest. Sorry if im wrong, hope this helps.

Answer:

In between and the middle one

Explanation:

Answer:

4 Newton

Explanation:

because you minus 1 Newton from 5 newton

The net force on the box is equal to 4N. Therefore, option (1) is correct.

The net force can be described as the vector sum of forces acting on a particle or object. The net force can be defined as a single force showing same the effect of the original forces on the particle's motion. Net force gives the same acceleration as all those actual forces together.

The net force becomes the resultant force. It has the same effect on the rotational motion as all actual forces taken together by the object. Force is a vector quantity as it has a magnitude and a direction.

In the given problem, the applied force is in the opposite direction of the frictional force so we can find the net force by subtracting these two forces.

Given, the applied force to push the box = 5N

The frictional force on the box, = 1 N

The net force on the box = 5N + (-1N) = 4N

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The power to stop the car with kinetic energy of a car is  \(8*10^{6} J\) as it travels along a horizontal road is  \(8*10^{5} watt\), option B

Kinetic energy can be seen as one that is been recorded when an object is able to move from a place , in a broad term we can say this is the energy that can be attributed to that of someone leaving a place and go to another place hence we can see it as the one in the motion.

The definition of energy as the "power to accomplish work" refers to the capacity to apply a force that moves an object. Even if the word is vague, it is clear what energy actually means: it is the force that causes objects to move. The two types  can be attributed to the one we know which are kinetic and potential energy.

\(Power \frac{Energy}{time}\)

\(Energy = 8*10^{6} J\)

\(time = 10 s\)

\(Power = \frac{8*10^{6} J}{10}\)

\(power = 8*10^{5} watt\)

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proper question;

The kinetic energy of a car is 8 × 106 J as it travels along a horizontal road. How much power is required to stop the car in 10 s? (A) zero joules (B) 8  105 J (C) 8  107 J (D)8  104 J (E) 8  106 J​

Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.

Answer and Explanation:

1. Evidence can be observed that light is energy-consuming because the liquid crystal sheet sets the temperature and gets warmer. With this, we can affirm that the light energy, moved the liquid crystal sheet molecules, making them when they move generate heat.

2. The evidence that light loads energy can be seen through the movement of the toy. This is because the light states that there was energy received, which will make all the gear of the toy work and move it.

(1) The evidence is the increase in the temperature of the liquid crystal sheet.

(2) The evidence that light carries energy can be seen through the movement of the toy.

The evidence that light carries energy can be observed through the increase in temperature of the liquid crystal sheet. The energy from the incident light increases the temperature of the liquid crystals.

The evidence that light carries energy can be seen through the movement of the toy. The photo-voltaic cell of the solar panel helps to convert solar energy into electricity that will power the toy, thereby creating movement of the toy.

Thus, light carries energy and it can be seen through the increase in the temperature of liquid crystals when light incidents on it and the movement of toy powered by solar energy.

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The answer is "Infrared"

Hope this helps

Answer:

x-rays

Explanation:

equal in magnitude but opposite in direction