A rock is thrown vertically up and reaches a maximum height of 20m. What was its initial velocity?

Answers

Answer 1

Answer:

Solve it simply,

Vi = 20 m /sec

Vf = 0 ( at max. height)

g = - 9.8 m/ sq. sec. ( -ve sign shows that the motion of the body is in opposite direction to that of gravity)

Height it gains=h = ?

time taken by the body=t=?

Using 3rd equation of kinematics,

2gh=Vf ˄2 – Vi˄2

implies that

h = Vf ˄2 – Vi˄2 / 2a

h = 0˄2 - (20)˄2 / 2(-9.8) = - 400/ -19.6

h = 20.4 m

So the maximum height the body can gain is approximately equal to 20.4 m.

Now , using 1st equation of kinematics:

Vf = Vi + at implies that,

t = Vf - Vi/g = 0 - 20/ - 9.8 = 2.04 sec.

So, it will take 2.04 sec. to get the max. height.

Note: in simple approximation if we take g =- 10 m/ sq.sec then the max. height the body can attain will be 20 m and the time required for it, is 2 sec.


Related Questions

is paper an insulator or a conductor?

Answers

Answer:

Paper is an insulator.

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Answer:

Paper is an insulator because it don't allow heat to pass or flow through them.

Conductor

•Are materials that can transfer heat easily.

•Allowing heat to transfer freely through them.

Ex: cooking pan

    silver

    metal spoon

    nail

Insulator

Are materials that do not allow heat to pass through them.

Ex: rubber

     wood

     leather

     plastic

     paper

A student runs an experiment in which a block of known mass is moving across a horizontal table in an xy-coordinate plane. As the block reaches the origin of the coordinate system, the block explodes into two pieces of masses m1 and m2. During the experiment, the velocity of the block 1.0 second before the explosion and the velocity of the two pieces 1.0 second after the explosion are measured using a motion sensor. Conservation of momentum is applied using the masses of the two pieces. However, when the velocity of the piece of mass m2 is calculated, the measured value is 10% less than the calculated value. Which of the following statements best explains the difference in the calculated and measured velocity?

Answers

The statement that best explains this difference is "As the block is moving across the table, friction will affect the block’s motion and thus could account for the difference" (option A).

What is friction?

In physics, friction can be defined as a force of resistance that occurs when an objects moves above a surface or above another object. Friction can be classified in four types:

Static friction: This is the type of friction when two objects are in contact agaisnt each other but there is no movement.Sliding friction: This type of friction occurs as one object moves over another.

How does friction affect the velocity of the object moving?

This force opposes the movement of the object and therefore it can affect the velocity of the object by decreasing it. Based on this, it is likely that the difference in the calculation is because of friction as this was not considered (option A).

Note: This question is incomplete; here is the missing section:

A. As the block is moving across the table, friction will affect the block’s motion and thus could account for the difference.

B. It is possible that a small amount of the original block was lost during the explosion.

C. When the student did the calculation, the student assumed that the explosion occurred just as the block reached the origin. The difference in velocity could be due to the explosion occurring either just before or just after the origin.

D. The explosion created a force that affected the experiment.

E. Conservation of momentum is not the correct equation to apply to the explosion, since the two pieces apply forces to each other.

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Answer:

The difference between the calculated and measured velocity of the piece of mass m2 can be attributed to several factors. Here are a few possible explanations:

1. Measurement error: It's possible that there were errors or inaccuracies in the measurements taken by the motion sensor. This could include issues with the sensor itself, calibration errors, or human error in recording the data.

2. Friction and air resistance: The experiment assumes an ideal scenario where there are no external forces acting on the block and the resulting fragments. However, in reality, there may be friction and air resistance present, which can reduce the velocity of the pieces after the explosion. These factors were not accounted for in the conservation of momentum calculations.

3. Internal forces: The explosion of the block into two pieces involves internal forces between the fragments. These forces may not be completely accounted for in the conservation of momentum analysis. If there are significant internal forces acting during the explosion, they could reduce the calculated velocity of the piece of mass m2 compared to the measured value.

4. Incomplete information: It's possible that there is additional information or factors that were not considered in the given description of the experiment. Without knowing all the details, it's challenging to pinpoint the exact reason for the discrepancy between the calculated and measured velocity.

In summary, the most likely explanation for the difference between the calculated and measured velocity of the piece of mass m2 is measurement error or the presence of external forces (such as friction and air resistance) and internal forces (during the explosion) that were not accounted for in the analysis.

Does anyone know how to find the mass of one piece of paper , printing paper to be exact

Answers

75 gsm is the mass of a piece of printing paper

4. In the image, a rubber balloon is being rubbed back and forth against a wool
scarf. Which of the following is true? *
The balloon lost some electrons to the scarf during the charging process.
The balloon lost all of its electrons to the scarf during the charging process.
After rubbing, the balloon has the opposite charge as the scarf.
The scarf would now be repelled by the balloon.

Answers

lost some electrons I think

a story that ends indeed God knows the best​

Answers

Answer:

In fact, God already knows how your story will end. The thing is, it’s really his story and he created you to be a unique and significant part of it. That’s why you can have faith that he is working to take care of you and to give you a good future. God repeatedly says in Scripture that he will one day reward us for our faith.

Good luck

Explanation:

Which of the following determines the natural frequency of an object?

A. Color

B. Pressure

C. Length

Answers

Answer:

C

Explanation:

The longer an object, the slower it vibrates and since frequency is the number of oscillations an object makes per second, then you can say the longer the object, the lower the frequency, and the inverse is true.

Are amplitude and wavelength related?
A: Yes
B: No

Answers

The answer is A.Yes

Explanation:

The amplitude of a wave is the height of a wave as measured from the highest point of the wave to the lowest on the wave.

If a capital letter R is seen in an ordinary mirror , what does it look like?

Answers

D would be the correct awnser it would just be a reflection

If a capital letter R is seen in an ordinary mirror, it will look like option D. The correct option is D.

What is a mirror?

Something that is reversed with respect to a previous instance of the same thing, or with respect to a plane or axis in between. The best illustration of a virtual image is a reflection in a mirror.

Real images are created by intersecting rays, and virtual images are created by diverging rays. A mirror creates a virtual image by reflecting a real image (blue) back to the viewer (red), giving the impression that the items in the image are behind the mirror's surface and facing the other way (purple).

The R in the mirror will look vertically inverse. The types of mirrors are plane mirrors, rotating mirrors, inclined mirrors, and spherical mirrors.

Therefore, the correct option is D.

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What game has worst Physics?​

Answers

Answer:

Cyberpunk has worst Physics

an object of mass 5 kg is raised above the ground calculate work done on the object.​

Answers

Answer:

work done on the body is the product of the 3 quantities provided

mass in kilogram, macceleration due to gravity in meters per seconds, gdistance or height in meters, h

Explanation:

Raising the object, the work done will be the potential energy.

potential energy equals mgh.

Get the remaining quantities and multiply it out g is usually 10m/s

a sprinter starting from rest reaches final velocity of 18.0 mi/h. What is her average velocity?

Answers

Answer:

9m/s

Explanation:

Average velovity= (Initial velocity+Final velocity)/2

or A.V=(0+18)/2

or A.V= 9m/s

A sprinter starting from rest reaches final velocity of 18.0 mi/h. The average velocity of the sprinter is 9.0 mi/h.

Given that the sprinter starts from rest and reaches a final velocity of 18.0 mi/h, we can assume that the sprinter accelerates uniformly. Therefore, her average velocity would be the average of her initial velocity (0 mi/h) and her final velocity (18.0 mi/h).

Average velocity = (Initial velocity + Final velocity) / 2

Average velocity = (0 mi/h + 18.0 mi/h) / 2

Average velocity = 18.0 mi/h / 2

Average velocity = 9.0 mi/h

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Using data from the diagram below, calculate the ratio of the height to which water at 0°C and mercury are raised or suppressed by capillary action in the same glass tube (use density and
surface tension values of water that are accurate to at least 3 significant figures for your calculation. Include the appropriate sign with your answer.)
water
mercury

Answers

Due to stronger cohesive than adhesive forces mercury levels falls in a capillary tube. However, water level rises in a capillary tube due to greater adhesive than cohesive forces.

What is capillary action?

Capillary action refers to the rise or fall of a liquid in a narrow tube.

The height to which a liquid is depressed or rises in a narrow tube depends on the strength of the cohesive forces of the molecules of the fluid compared to the adhesive forces between the molecules of the fluid and the walls of the tube.

In water, the adhesive forces between the walls of the tube and water molecules is greater than the cohesive forces between water molecules, hence water rises in a capillary tube.

In mercury the adhesive forces between the walls of the tube and water molecules is less than the cohesive forces between mercury molecules, hence mercury levels falls in a capillary tube.

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Which of the vectors in the graph below is the negative of the vector v?

Answers

Answer:

D

Explanation:

Answer:

A. D

Explanation:

A tennis ball has a mass of 57 g. A tennis player hits the tennis ball with a tennis racket. The tennis ball has a velocity of 25 m / s when it hits the racket. The velocity of the tennis ball when it leaves the player’s racket is 15 m / s in the opposite direction from its approaching direction. The average force exerted by the tennis racket on the ball is 35 N. For how long is the tennis ball in contact with the tennis racket?​

Answers

Answer:

0.065 seconds

Explanation:

i) Change in momentum is equal to impulse so, m(v-u) = ft  (Where f is force and t is time)

ii) Since we know the mass of the ball, we change grams to the SI unit of kilograms, kg so 0.057kg

iii) We are also told that the ball CHANGES direction, so we know that the new velocity is the negative value of the initial one,

iv) Putting this all together we get 0.057(25--15) which is the same as 0.057(25 + 15)

v) We get an impulse of 2.28 Ns

vi) We take this value and divide it by 35 as we want the Force alone and not the time,

vii) To which we get 0.065 seconds,

Hope this was helpful!!

What are the units for the spring constant k?

Answers

Answer:

F=k*x or

k is the spring constant, in Newtons per meter (N/m), and x is the displacement of the spring from its equilibrium position. The spring constant, k, is representative of how stiff the spring is. Stiffer (more difficult to stretch) springs have higher spring constant

Explanation:

Answer:

N/m

Explanation:

Spring force is defined as

F=kx

So,

the terms for spring constant can be rearranged to find

F/x =k

which simplifies to

N/m

since force F is in newtons, and displacement x is in meters.

complete these sentences by crossing out the incorrect words.

The greater the amplitude of a wave, the ( less/more ) energy it is transferring. As waves spread out from a source, the energy they transfer gets more ( concentrated/ spread out ) and so the amplitude of the waves gets ( larger/ smaller)​

Answers

Answer:

The greater the amplitude of a wave, the ( less/more ) energy it is transferring.

The more energy; so that means less would be the incorrect word

As waves spread out from a source, the energy they transfer gets more ( concentrated/ spread out )

Spread out; so that means concentrated would the be the incorrect word

and so the amplitude of the waves gets ( larger/ smaller)​

Smaller; so that means larger is the incorrect word

a rectangular container measuring 20cmX20cmX30cm is filled withn water.What is the mass of the voulme of water in kilogram and in grams?

Answers

Answer:

12,000 grams = 12 kg

Explanation:

Volume V = 20 x 20 x 30 cm³ = 12,000 cm³

density of water d = 1 g/cm³

so the mass is 12,000 grams = 12 kg

7. A golfer hits a golf ball a through a horizontal displacement of 80m. The time of flight for the ball was 1.8
seconds. Keeping it simple, ignoring friction and the ball's rotation, determine the velocity (magnitude and
direction) of the ball as it left the golfer's club.

Answers

Answer:

44.4 m/s

Explanation:

d = 80 m, t = 1.8 s, find v

d = v*t

v = d/t = 80/1.8 = 44.4 m/s

Solve and show conversions

Answers

Answer:

°c to °F = 176°F

°c to K = 353 K

Explanation:

1, °c to °F = (°c × 9/5) +32

[tex](80 \times \frac{9}{5} ) + 32[/tex]

(16 × 9) + 32 = 144 + 32 = 176°F

2, °c to K = °c + 273

[tex]80 + 273[/tex]

= 353 K

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The speed in Case A is twice that of Case B. The object mass
in Case A is one-half that of Case B. The radius is the same
in each case. How does the net force in Case A compare to
the net force in Case B?

Answers

Answer:

one-half that of Case B.

Explanation:

I am sorry if I get it wrong

ghghghghghg gh gh gh gh gh gh

Answers

Ghghghghghghghghghghgh

Answer:

Explanation:

this is a wste of time and question people realy want to learn in this page.

19) Study the chart above. Which statement is TRUE regarding natural and synthetic (manufactured) fibers?
A) Glass is a natural material.
B) Staple fibers do not come from animals.
C) Organic manufactured materials are either synthetic or natural plastics.
D) Synthetic polymers including polyester and nylon, make up a large category of synthetic material.

Answers

Answer: The answer is D: Synthetic polymers including polyester and nylon, make up a large category of synthetic material.

Explanation:

During Taylor's second test of a car with a mass of 200 grams, she recorded 11 seconds, 11.4 seconds, and 11.2 seconds for her 3 trials. What would be the mean value she would use to compare with the other cars?

11.53 seconds

33.6 seconds

11.2 seconds

11 seconds

Answers

Answer:

C. 11.2 seconds

The mean value of three trials of 11, 11.4 and 11.2 seconds will be 11.2 seconds

What is mean?

The mean for any data is defined as the ratio of the sum of all the data to the number of the data.

It is given that

[tex]t_1=11\ \ \ \ \ \ \ \ t_2=11.4 \ \ \ \ \ \ \ \ t_3=11.2[/tex]

Now the mean is given as

[tex]\rm Mean=\dfrac{t_1+t_2+t_3}{N}[/tex]

[tex]\rm Mean=\dfrac{11+11.4+11.2}{3}=11.2 \ Sec[/tex]

Hence the mean value of three trials of 11, 11.4 and 11.2 seconds will be 11.2 seconds

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Captain Picard beams down to a previously unexplored planet. The planet has four times the mass of Earth, and twice the radius. If the force of gravity on the surface of Earth is represented by "g," what is the force of gravity on the surface of the new planet?
A. g
B. 2g
C. 4g
D. 8g

Answers

The force of gravity on the surface of the new planet is g

Option A is correct

The force of gravity on the surface of the new planet

Force of gravity: the force of gravity speaks to the force that acts on every body that exists under a given space or planet.

The force of gravity acts on masses to create weight.

W=mg

Generally the equation for the Force of gravity is  mathematically given as

[tex]g=\frac{Gme}{Re^2}\\\\Therefore\\\\g'=\frac{G*4Me}{2Re^2}\\\\g=4/4\frac{GMe}{Re^2}\\\\[/tex]

g=1g

Therefore, the force of gravity on the surface of the new planet is g

Option A is correct

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How does the electric force between two charged particles change if the
distance between them is reduced by a factor of 2?
A. It is reduced by a factor of 4.
B. It is reduced by a factor of 2.
C. It is increased by a factor of 4.
ОО
D. It is increased by a factor of 2.

Answers

Answer:

D

Explanation:

If the distance is reduced by factor of 2, lets say the distance was 10cm

reducing by a factor of 2 will leave the distance at 5cm

so the electric force increases by a factor of 2

Why does the Law of Conservation of Matter/Mass/Energy support climate change research?
A. The energy we use constantly being destroyed.
B. The energy we use is created every time we use electricity
C. The energy we use cycles throughout our world, always balanced, creating a stable climate.
D. The energy we use is released into the atmosphere, creating loop of continual absorption and releasing of heat

Answers

The law of conservation of energy supports climate change research because the energy we use is released into the atmosphere, creating loop of continual absorption and releasing of heat.

Law of conservation of energy

The law states that energy can neither be created nor destroyed but can always be converted from one form to another.

In light of this, any energy used by humans or natural processes is not destroyed. Instead, they are converted into another form or released into the atmosphere.

In the atmosphere, absorption and release of heat energy by greenhouse gases and irradiation create a loop. This loop causes a net heating or cooling of the planet, a phenomenon that affects the climate.

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A steam governor uses negative feedback to control the speed of a steam engine. Suppose a steam governor
has two balls that are each rotating with a tangential speed of 3.7 m/s. The balls are 0.10 m from the rotation
axis, and the centripetal force on each ball is 670 N. What is the mass of one of the balls?

Answers

Answer:

F = M a       Newton's second law

a = v^2 / R = (3.7 m/s)^2 / .10 m = 137 m/s^2

M = F / a = 670 N / 137 m/s^2 = 4.89 kg

The energy that can be extracted from a storage battery is always less than the energy that goes into it while it is being charged. Why?​

Answers

The simplest answer would be that the battery has internal resistance, and the leads do to, so part of the energy is lost to heat during the charging process. In addition, the power conversion in the battery is less than perfect, giving more losses. The extraction of power is accompanied by more losses - in the battery, and in the wiring.

This is because no battery or energy storage device is 100% efficient, meaning that some of the energy that goes into charging the battery is lost as heat or other forms of energy during the charging process.

This loss of energy is due to several factors, including resistance in the battery's electrical components, chemical reactions that occur within the battery during charging, and other inefficiencies in the charging process.

As a result, when the battery is discharged, it cannot release all the energy that was originally put into it during charging, and some of the energy is lost as heat or other forms of energy. This is known as energy loss or energy dissipation, and it is a common occurrence in all types of energy storage systems.

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a
A tennis ball is hit vertically
upward with a velocity of 30 ms-1.
It takes 3 s to reach the highest
point. Calculate the maximum
height reached by the ball. How
long it will take to return to
ground?

Answers

h=vot-1/2gt²

h=30 x 3 - 1/2 x 9.8 x 3²

h = 45.9 m

t = 2to

t = 2 x 3 = 6s

What is the power in watts of a 6-A
appliance designed to operate on a 120-V circuit?

Answers

Answer:

720W

Explanation:

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