You place a block of wood on a table. How could you increase the pressure
the block exerts on the table?
O
A. Turn it to a larger face.
O
B. Move it to the floor.
O
C. Hold it above the table.
O
D. Turn it to a smaller face.

Answer:

D. gravity

Explanation:

Gravity keeps the atmosphere from escaping into space.

The intensity of X-ray beam of second exposure made at 100 cm SID is 20 mR.

Solution:

By using inverse square law formula, intensity of X-Ray beam made at different distances can be found.

[tex]\frac{I_{1}}{I_{2}}=\left(\frac{D_{2}}{D_{1}}\right)^{2}[/tex]

Where [tex]I_1[/tex] is the intensity of first exposure of X-ray-beam.

[tex]I_2[/tex]  is the intensity of second exposure of X-ray beam.

[tex]D_1[/tex]  is the distance at which first exposure is made.  

[tex]D_2[/tex]  is the distance at which second exposure is made.

[tex]\begin{array}{l}{\frac{I_{1}}{I_{2}}=\left(\frac{100}{200}\right)^{2}} \\\\ {\frac{5}{I_{2}}=\frac{1}{4}} \\\\ \bold{{I_{2}=20\ \mathrm{mR}}\end{array}}[/tex]

Answer:

The average speed of the marathon runner is 5.15 meters per second

Explanation:

Lets revise the meaning of average speed

The average speed of an object is the total distance traveled by

the object divided by the time taken to cover that distance

A marathon runner runs at a average speed of 5.33 meters per second

for the first  3600 seconds

⇒ His speed = 5.33 m/s

⇒ For time = 3600 seconds

Then he runs at a speed of 5.00 meters per second for the next

4200  seconds

⇒ His speed is 5 m/s

⇒ For time 4200 seconds

Average speed = total distance ÷ total time

Lets find the total distance

Distance = speed × time

⇒ The 1st distance = 5.33 × 3600 = 19188 meters

⇒ The 2nd distance = 5 × 4200 = 21000 meters

⇒ Total distance = 19188 + 21000 = 40188 meters

Lets find the total time

⇒ Total time = 3600 + 4200 = 7800 seconds

⇒ Average speed = 40188 ÷ 7800 = 5.15 m/s

The average speed of the marathon runner is 5.15 meters per second

the answer is Friction.

hope this heslp

Micro welds are formed where bumps from two surfaces come into contact.

Explanation:

The surface of all existing objects or elements, have some bumps and dips. Whenever the surfaces of two different bodies with bumps and dips come into contact with each other, sticking occur.

This causes the production of micro welds between the two surfaces that inhibit the smooth motion. These micro welds create a static force that opposes the smooth motion between the surfaces. This is called “friction”.

This friction force can be stopped only when it can either be dominated with the equal opposite force or inhibited with lubricating agents that reduce its effect on the surfaces of the two respective objects.

1.

Answer:

m = 74.9 kg

Explanation:

As we know that weight of the object is force due to gravity

Now we know that

[tex]F_g = mg[/tex]

[tex]m = \frac{F_g}{g}[/tex]

[tex]m = \frac{735}{9.81}[/tex]

[tex]m = 74.9 kg[/tex]

2.

Answer:

[tex]s = 450 J/kg ^oC[/tex]

Explanation:

Heat added to the system is given as

[tex]Q = ms\Delta T[/tex]

so we will have

[tex]337500 = 50 s (15)[/tex]

[tex]s = 450 J/kg ^oC[/tex]

3.

Answer:

Velocity will increase while acceleration will remain constant

Explanation:

When skydiver falls from rest then velocity will increase with time while the acceleration due to gravity will remains constant.

So here we can say that

[tex]a = 9.81 m/s^2[/tex]

while velocity will increase while it falls from certain height

Answer:

D: all of the other 3 answer choices

Explanation:

Milli- is a prefix, so a lowercase m in front of any other letter means milli-.  For example, mm = millimeter and mg = milligram.

An m by itself means meters.

Answer:

D: all of the other 3 answer choices.

Explanation:

A: a prefix is never used alone. So a lone m (lower case) would refer to a unit, the meter (the SI metric unit of length.)

Above statement is true because here we can see that when prefix is placed before any SI unit then only we use it let say if we use only unit "m" then it is clearly assumed to be meter

B: the prefix Comes before the unit, so mm (both lower case) would stand for millimeter.

TRUE

Since prefix is always used before SI unit then we have to use the prefix like it is shown here for length. when we give unit as "mm" then it will show millimeter.

C: the prefix comes before the unit, so mg (both lower case) would stand for milligram.

TRUE

Since prefix is always used before SI unit then we have to use the prefix like it is shown here for mass. when we give unit as "mg" then it will show milligram.

Answer:

If enough evidence accumulates to support a hypothesis, it moves to the next step (known as a theory) in the scientific method and becomes accepted as a valid explanation of a phenomenon.

Answer:

Hypothesis is usually referred as an assumption or an observation made without much proof to support the statement. Hence scientists and experimental physicists uses hypothesis and perform experiments and observations to support the theory.

The hypothesis will get transformed into a theory only when there is enough evidence to support the cause and the science behind the set of events. It is dependent upon a number of scientific tests an hence it is not possible to define a time period. It may varies from years to forever (or never).

Answer:

1/4

Explanation:

P = IV, and V = IR, so P = I²R.

If R is held constant, and I is cut in half, then power becomes:

P = (I/2)²R

P = 1/4 I²R

So the power reduces by a factor of 4.

The resistor change 1/4

P = IV, and V = IR, so P = I²R.

If R is held constant, and I is cut in half, then power becomes:

P = (I/2)²R

P = 1/4 I²R

So the power reduces by a factor of 4.

The resistance of all substances modifications to their temperature modifications. If the temperature is diminished, resistance (commonly) declines. In fact, if cooled sufficiently, the material becomes a "superconductor" without huge resistance. Increasing the temperature (normally) will increase resistance.

If you boom the wide variety of lamps in a sequence circuit, there will be less modern-day. The lamps resist modern-day, so in case you placed extra lamps into the circuit, there may be more resistance. You can increase or lower the resistance in a circuit through the usage of a variable resistor.

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Answer:

Physics

Chemistry

Explanation:

Physical science is science which studies non-living things.This covers things on earth to the universe.The main branches are physics and chemistry.The other sub-branches are Astronomy, meteorology and Geology.Physics is concerned with the basic principals of matter and energy.It covers concepts in motion, energy, force, pressure , light and many other areas we encounter in our day to day life.Chemistry is concerned with composition of matter and how it reacts.Material in chemistry is understood through observing molecules, atoms, elements and their interaction in nature including their properties.Chemistry is further divided into organic chemistry and natural chemistry sub-branches.

Answer:

a. change in state

Explanation:

Separation of iron filings from its mixture with sulphur is an example of mixing and separation.

Answer: B.  mixing and separation

Explanation:

Separation techniques exploit various physical and chemical properties of substances. When a mixture undergoes separation it may result in two or more mixtures or even pure substances. Here separation of iron filings is achieved by making use of the magnetic property of iron.

Very few substances occur in pure form in nature. In order to obtain pure substances various separation techniques have to be employed. Examples of separation techniques are chromatographic separation, centrifugation, electrophoresis etc...

Answer:

11:1

Explanation:

At constant acceleration, an object's position is:

y = y₀ + v₀ t + ½ at²

Given y₀ = 0, v₀ = u, and a = -g:

y = u t − ½g t²

After 6 seconds, the ball reaches the maximum height (v = 0).

v = at + v₀

0 = (-g)(6) + u

u = 6g

Substituting:

y = 6g t − ½g t²

The displacement between t=0 and t=1 is:

Δy = [ 6g (1) − ½g (1)² ] − [ 6g (0) − ½g (0)² ]

Δy = 6g − ½g

Δy = 5½g

The displacement between t=6 and t=7 is:

Δy = [ 6g (7) − ½g (7)² ] − [ 6g (6) − ½g (6)² ]

Δy = (42g − 24½g) − (36g − 18g)

Δy = 17½g − 18g

Δy = -½g

So the ratio of the distances traveled is:

(5½g) / (½g)

11 / 1

The ratio is 11:1.

The elephant and the mouse having zero weight in a gravity free space will not bump into you at the same effect.

Explanation:

When both are in a gravity free space, the weights are zero, as we know that the[tex]\text {weight of the body}=\text {mass of the body} \times \text {acceleration due to gravity}[/tex]

[tex]\text {here, the weight of elephant}=\text {mass of elephant } \times \text {zero gravti} y=zero[/tex]

[tex]\text {similarly,weight of mouse}=\text {mass of mouse } \times \text {zero gravity}=zero[/tex]

But when they will acquire the speed of same magnitude, say v, their different masses will acquire different momentum, which will make the difference in effect while bumping.  

[tex]\text { momentum of elephant }=\text { mass of elephant } \times v[/tex]  [tex]\text { momentum of mouse = mass of mouse } \times v[/tex]

And as we know [tex]\text { mass of elephant }>\text { mass of mouse }[/tex]  Therefore, effect of impact by elephant will be more than that of mouse . An elephant breaking into you will take you back faster than a mouse in space hits you.

Answer:

it would be d

Explanation:

because the neutron has a neutral charge so it has no charge at all

A neutron is electrically neutral and has a similar mass to a proton, which has a positive charge. While they both are part of the nucleus and contribute to an atom's mass, only the proton's charge affects the atom’s chemical properties. So the correct option is D.

Comparing a neutron and a proton, option D is the correct answer: The proton has a positive charge, while the neutron has no charge. Both neutrons and protons reside in the nucleus of an atom and have approximately the same mass, which is about 1.67 × 10-24 grams, also known as one atomic mass unit (amu) or one Dalton. However, they differ significantly in terms of their electric charge. A proton has a positive charge (+1), essential in determining the atomic number and the chemical properties of an element. In contrast, a neutron is electrically neutral, carrying no charge at all, and contributes to the mass of an atom without affecting its electric charge. The number of protons and neutrons in the nucleus can vary; in a neutral atom, the number of electrons, which are negatively charged, is equal to the number of protons, balancing the net charge to zero.

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Answer:

a. 104°F

b. 86°F

Explanation:

To convert Celsius to Fahrenheit, use the equation:

F = 1.8C + 32

where F is the temperature in Fahrenheit and C is the temperature in Celsius.

a. F = 1.8(40) + 32

F = 104

b. F = 1.8(30) + 32

F = 86

(A) [tex]40^{\circ}C[/tex] equals [tex]104^{\circ}F[/tex]and (B)[tex]30^{\circ}C[/tex] equals [tex]86^{\circ}F[/tex].

To convert temperatures from degrees Celsius to degrees Fahrenheit, we can use the following formula:

[tex]F = \left( C \times \frac{9}{5} \right) + 32[/tex]

Let's use this equation to get the specified temperatures:

[tex]F = \left( 40 \times \frac{9}{5} \right) + 32 \\\\F = 72 + 32 \\\\F = 104^\circ\text{F}[/tex]

[tex]F = \left( 30 \times \frac{9}{5} \right) + 32 \\\\F = 54 + 32 \\\\F = 86^\circ\text{F}[/tex]

Explanation:

In a vacuum (no air resistance), it doesn't.  All falling objects, regardless of mass, accelerate at the same rate.

However, when air resistance is taken into account, heavier objects indeed fall faster than lighter objects, provided they have the same shape and size.  For example, a lead ball falls faster than a styrofoam ball.

To understand why, first look at what factors affect air resistance:

D = ½ρv²CA

where ρ is air density,

v is velocity,

C is drag coefficient,

and A is cross sectional area.

As falling objects accelerate, they eventually reach a maximum velocity where air resistance equals weight.  This is called terminal velocity.

D = W

½ρv²CA = mg

v = √(2mg/(ρCA))

If we increase m while holding everything else constant, v increases.  So two objects with the same size and shape but different masses will have different terminal velocities, with the heavier object falling faster.

Before you ask why, you need to know whether.

On the moon, or any other airless body, all objects fall together, no matter how much each one weighs. We've known this for a good 500 years.

On Earth, if one object falls slower, it's only because the air caught it and held it back.

Explanation:

Given , F = 30N and mass m = 90kg

°•° F = ma

=> a = F/m

=> a = 30/90

=> a = 1/3m/s^2

Final answer:

To find the acceleration of a 90 kg box with a force of 30 N applied, use Newton's second law of motion. The acceleration is calculated as 0.333 m/s².

Explanation:

To calculate the acceleration of a 90 kg box when a force of 30 N is applied, we can use Newton's second law of motion, which is F = ma, where F is the force applied, m is the mass of the object, and a is the acceleration of the object. Rearranging the equation for acceleration gives us a = F / m.

In this case, F = 30 N and m = 90 kg. Plugging these values into the equation yields a = 30 N / 90 kg = 0.333 m/s². Therefore, the acceleration of the box is 0.333 meters per second squared (0.333 m/s²).

Answer:

First you have to determine the angle of the vectors. Based on this angle, you separate the horizontal and vertical components using the trigonometric functions sine and cosine. The horizontal component is solved independently from the vertical, and finally using the Pythagorean Theorem, you solve the combined answer of the vertical and horizontal components to reach your final answer.

Answer:

Resolve each vector into it's x and y components

Answer:

circle graph

Explanation:

A circle graph it is a statistical resource that is used to represent percentages and proportions. The number of elements compared within this graph can range from two to as many as required. Thus, Using this graph you can visualize the proportion of each expense, like food and housing, with respect to the total monthly income.

Answer:

circle graph

Explanation:

did the test

The natural sources of water pollution are algae blooms.

Answer: Option C

Explanation:

The natural form of water pollution is due to water erosion, the composition of minerals, leaves, human/animal droppings, etc. Algae blooms are the development of phytoplankton (a tiny floating plants in fresh and salt water).

Algae bloom also causes problems in the aquatic ecosystem. The excessive algae can block sun rays and hence affect important aquatic habitats.

This can also be seen in the fish gills and inhibit their breathing. When a significant bloom of algae dies, they can damage the available oxygen in the water and make it uninhabitable for other life forms.

Answer:

C. Algae blooms

Explanation:

Algae blooms grow largely and rapidly in fresh and marine water. It discolors the water. These can produce toxins in water and are very harmful for marine life as it blocks the sunlight from reaching the depth. Also, marine life struggles to find food and eventually leaves the area. It also badly impacts the local economy. It is the natural source of water pollution.

Answer: Ionization energy is the amount of energy necessary to remove an electron from an atom

Explanation:

Ionization consists of the production of ions, which are electrically charged atoms or molecules due to the excess or lack of electrons with respect to a neutral atom or molecule.

In this sense, ionization energy is the energy necessary to separate (remove) an electron from a gaseous atom, isolated and in a fundamental state. This is because electrons are strongly attracted to the nucleus and it is necessary to provide energy to separate them. However, where the atom always loses electrons is in the last layer, which is where the weakest electrons are attracted to the nucleus.

Answer:

143.325 pounds (rounded to 8 digits, but you can round it to a lower amount of digits if you need to!)

Explanation:

So 1 kg = 2.205 lbs, so 65 kg = 2.205lbs * 65kg, which is equal to approximately 143.325 lbs.

( 1kg = 2.205lbs; 65 kg = ? lbs)

Answer:

The metric system measures mass in grams or kilograms, distance in meters or kilometers, and volume in liters. It measures temperature in Kelvin or Celsius degrees instead of the Fahrenheit degrees used in the imperial system.

Answer:

The mass of a body is a measure of the resistance against a change of motion state of the body itself. That's why they usually call it "inertial mass" and is somehow an exclusive property that doesn't depend on "where" the body is in the space.

The volume of a body literally the amount of three-dimensional space that the body occupies.

The temperature of a body is a measure of the kinetic energy that the body has. The more the atoms of the body are moving, the hotter the body will be. Absolute zero (i.e. 0° K) is a state where all of the atoms of a body are motionless.

With reference to the international system of units, mass is measured in kilograms, volume in cubic metres and temperature in Kelvin.

Answer:

a) Both balls are affected by gravity in the same way. The time both balls hit each other is equal to the time the ball thrown up reaches the top of the roof, if there was no gravity. (both balls would be at the same location)

y = v*t = 85m = 46m/s * t

t = 1.85s

Check:

The equation for position is given by:

y(t) = -0.5gt² + v₀t + x₀

The position of the ball on the roof top at time t = 1.85s:

y₁(t) = -4.9t² + 85.0 = 68.3m

The position of the ball thrown up at time t = 1.85s:

y₂(t) = -4.9t² + 46 * 1.85 = 68.3m

b) the two balls hit each other at a hight of 68.3m

The ball dropped from the building hits the ground after approximately 4.16 seconds. The ball thrown upward from the ground hits the ground after approximately 9.39 seconds. Both balls hit at the ground level.

This question involves the concepts of motion in Physics. We'll use the formulas for kinematic motion to find out when and where the two balls hit. First, let's consider the ball that's dropped.

The ball drops with an initial speed of 0 m/s as the ball is released from rest and it will cover a distance of 85.0 meters under the acceleration due to gravity. We use the second equation of motion: s = ut + 0.5gt^2. Here, s is the displacement (85 meters), u is the initial speed (0 m/s), g is the acceleration due to gravity (9.8 m/s^2), and t is the time we wish to determine. Plugging the known values, we find t = sqrt(2s/g) which gives us t ≈ 4.16 seconds.

Now for the ball thrown upwards from the ground with an initial speed of 46.0 m/s. The ball goes upwards, then slows down, stops and starts falling down under gravity. The time when the ball hits the ground is twice the time it takes for the ball to reach the highest point. That time is given by t = u/g (since at the highest point, final velocity is 0). Thus, the total time is T = 2u/g, which gives us T ≈ 9.39 seconds.

As for where they hit, the ball dropped from the building hits the ground, and the ball thrown upwards from the ground hits the ground again after it reaches the maximum height and falls back.

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Answer:

There should be only one manipulated variable within a scientific experiment so that the experimenter can be certain it is this variable which causes a pattern in the resultant data, if any exists at all. ... A variable within a scientific experiment is something that is changed

Explanation:

Answer:

There should be only one manipulated variable within a scientific experiment so that the experimenter can be certain it is this variable which causes a pattern in the resultant data, if any exists at all. ... A variable within a scientific experiment is something that is changed (i.e. it varies).yes here is correct

Liquid. Liquids have a definite volume but take up the shape of whatever they are in.

Happy to help!

Answer:

Explanation:

First, since the engineer is a slowpoke and he reacts a third of a second too late, the train will have 330 - 0.29*25 = 322,75 meters to stop. now, be [tex]x[/tex] (with [tex]x>0[/tex]) the deceleration value for which the train bumps at the car and stops, you have two conditions:

[tex]\left \{ {{25t-\frac12xt^2 = 322.75} \atop {0=25-xt}} \right.[/tex]

First states how much space the train has to stop, and the second tetermines how fast it slows down.

Solving the second for t, substituting in the first, and solving for x gives you a value of approximately [tex]1.94 m/s^2[/tex].

As usual, double check the calculations for yourself, it's always a good practice

Answer:

18.8 m/s

Explanation:

Given:

v₀ = 6.3 m/s

a = 3 m/s²

Δx = 52 m

Find: v

v² = v₀² + 2a(x − x₀)

v² = (6.3)² + 2(3)(52)

v² = 351.69

v ≈ 18.8

The final velocity is approximately 18.8 m/s (round as needed).

Answer:

It takes the bird 0.6875 hour to fly 22 km

Explanation:

Lets revise the relation between the distance, speed and time

→ Distance = speed × time

→ Speed = distance ÷ time

→ Time = distance ÷ speed

A bird can fly at 32 km/h

The speed of the bird is 32 km/h

The bird will fly 22 km

We need to find the time it takes the bird to fly this distance

The speed = 32 km/h

The distance 22 km

Lets use the rule:

→ Time = distance ÷ speed

→ Time = 22 ÷ 32 = 0.6875 hour

It takes the bird 0.6875 hour to fly 22 km

Answer:

6 m/s

Explanation: