b) A stone is dropped from the roof of a four storey building. The height of
each storey is 4.9m . Taking g =9.8m/s2 , calculate the velocity with
which the stone will hit the ground.

Answers

Answer 1

Answer:

9.8m/s

Explanation:

Given,

distance of each storey () = 4.9m

distance of 4 storey (s) = 19.6m

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

time given (t) = ?

velocity = (?)

initial velocity (u) = 0 {due to fall from certain height}

using formula,

s = ut + 1÷2at^2

s = 0 + 9.8÷2×t^2

19.6×2÷9.8 = t^2

4 = t^2

t = 2

now,

velocity ( v )= s ÷ t

v = 19.6 ÷ 2

v = 9.8 m/s

ans


Related Questions

2.Suppose you lifted the ring when the counter-clockwise orbiting marble was at the top of the circle. Describe the direction of the path that the marble would take.

3. Explain why the marble moved the way it did with the ring in place.

4. Explain why the marble moved the way it did when the ring was removed.

Answers

Answer:

3. The marble's trajectory was constantly being changed by running into the ring, forced it to move along the shape of the ring.

4. Once the ring was removed, the marble's momenum kept it going in a straight path as the ring was no longer forcing it to turn.

Explanation:

Ignoring air resistance, if a 20 kg ball and a 400 kg crate were both dropped from the
top of a building, the acceleration of the crate would be
the acceleration
of the ball.

Answers

The crate’s acceleration is gravity= 9.81m/s^2
The ball’s acceleration is also gravity=9.81m/s^2


A block slides to the right on a rough horizontal surface. The forces exerted on the block are shown above. Which of the following statements about the frictional force Ff exerted on the block is true?


A) It is the only force acting on the block that is caused by microscopic interactions.


B) It does not depend on the materials that the block and the surface are made of.


C) It is caused by gravitational interactions between the atoms in the block and the atoms in the surface.


D) It is the sum of all the microscopic contact forces between the bottom of the block and the surface.

Answers

Answer:

The correct option is;

A) It is the only force acting on the block that is causes by microscopic interactions

Explanation:

The force of friction is the force due to the relative motion of two surfaces in the presence of a perpendicular force acting between the surfaces.

The force of friction comes into play from the additional effect of the adhesion that is present between surfaces, the roughness of the surfaces, the contamination or deformation of the surfaces which is generated by the microscopic interactions be between the two surfaces, rather than the applied force.

The characteristics of the friction force, you can find which statements are correct:

   D) It is the sum of all the microscopic contact forces between the bottom of the block and the surface.

The force is an image of the interactions between bodies, these interactions create binding energy that can be formed and broken, the friction force is the macroscopic sum of all these microscopic interactions between two different surfaces.

The magnitude of the friction force depends on the type of each surface, on rough surfaces the interaction area is high, therefore the friction force is high, on smooth surfaces the interaction area is small, therefore the force is small, a way to create superficiality is to place a layer of air between the two surfaces.

Based on these explanations, let's review the different statements:

A) False. The friction forces are caused by interaction, but between two bodies not within the same body, this is what maintains the shape and volume of the body.

B) False. The contact area depends on each surface and therefore each type of material

C) False. The gravitational force is this in the line of interaction between the two bodies, in this case the force is perpendicular to movement, not in the line of interaction.

D) True. It is the sum of the interactions in the contact between the two bodies, it agrees with the explanation above.

Using the characteristics of the friction force, we can find the statements that are correct is:

   D)  It is the sum of all the microscopic contact forces between the bottom of the block and the surface.

 

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When you ride your bike around a corner at 10 m/s, you are accelerating?

Answers

When you ride your bike around a corner at 10 m/s, you are accelerating. Acceleration is caused by any forces. Sliding friction keeps you in the seat when a car goes around a corner. If you throw a ball into the air, Earth exerts a force on the ball.

Answer:

yes because acceleration is a vector quantity and as u turn around a corner you are changing direction.

Explanation:

Considering the activity series given for nonmetals, what is the result of the below reaction? Use the activity series provided. F > Cl > Br > I

Br2 + NaF Right arrow.



no reaction
Na + FBr2
NaBr + F2
Na2F + Br2

Answers

Answer:

A.) no reaction. Edge 2020.

Explanation:

There will be no reaction.

The activity series is also known as the reactivity series. It arranges elements in order of reactivity.

Given the activity series; F > Cl > Br > I, we need to predict whether the reaction; Br2 + NaF will proceed or not.

Looking at the reaction, Br is less than F in the activity series so Br can not displace F in NaF. Hence, there will be no reaction.

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An object is launched at a velocity of 20 m/s in a direction making an angle of 25° upward with the horizontal. (Given gravity g =9.8 , sin 25° = 0.42 and cos 25° =0.91) What is the maximum height reached by the object at B?​

Answers

Answer:

Explanation:

a) The formulas for the components Vx and Vy of the velocity and components x and y of the displacement are given by x = V0 cos(θ)       Vy = V0 sin(θ) - g t

x = V0 cos(θ) t       y = V0 sin(θ) t - (1/2) g t2

In the problem V0 = 20 m/s, θ = 25° and g = 9.8 m/s2.

The height of the projectile is given by the component y, and it reaches its maximum value when the component Vy is equal to zero. That is when the projectile changes from moving upward to moving downward.(see figure above) and also the animation of the projectile.

Vy = V0 sin(θ) - g t = 0

solve for t

t = V0 sin(θ) / g = 20 sin(25°) / 9.8 = 0.86 seconds

Find the maximum height by substituting t by 0.86 seconds in the formula for y

maximum height y (0.86) = 20 sin(25°)(0.86) - (1/2) (9.8) (0.86) 2 = 3.64 meters

b) The time of flight is the interval of time between when projectile is launched: t1 and when the projectile touches the ground: t2. At t = t1 and t = t2, y = 0 (ground). Hence

V0 sin(θ) t - (1/2) g t2 = 0

Solve for t

t(V0 sin(θ) - (1/2) g t) = 0

two solutions

t = t1 = 0 and t = t2 = 2 V0 sin(θ) / g

Time of flight = t2 - t1 = 2 (20) sin(θ) / g = 1.72 seconds.

c) In part c) above we found the time of flight t2 = 2 V0 sin(θ) / g. The horizontal range is the horizontal distance given by x at t = t2.

range = x(t2) = V0 cos(θ) t2 = 2 V0 cos(θ) V0 sin(θ) / g = V02 sin(2θ) / g = 202 sin (2(25°)) / 9.8 = 31.26 meters

d) The object hits the ground at t = t2 = 2 V0 sin(θ) / g (found in part b above)

The components of the velocity at t are given by

Vx = V0 cos(θ)       Vy = V0 sin(θ) - g t

The components of the velocity at t = 2 V0 sin(θ) / g are given by

Vx = V0 cos(θ) = 20 cos(25°)       Vy = V0 sin(25°) - g (2 V0 sin(25°) / g) = - V0 sin(25°)

The magnitude V of the velocity is given by

V = √[ Vx2 + Vy2 ] = √[ (20 cos(25°))2 + (- V0 sin(25°))2 ] = V0 = 20 m/s

Which is true A. You can see both lunar and solar eclipses from outside the shadow.B. You can see neither lunar and solar eclipses from outside the shadow. C. You can see only lunar from outside the shadow. D. You can see only solar eclipses from outside the shadow. .plz.help

Answers

Answer:

A

Explanation:

A lunar eclipse occurs when the Moon enters the Earth's shadow. A solar eclipse occurs when the Moon's shadow falls on the Earth. They do not happen every month because the Earth's orbit around the sun is not in the same plane as the Moon's orbit around the Earth.

which of the following is NOT a physical property of matter
A:Thermal Conductivity
B:Reactivity to water
C:Collor
D:Ductility​

Answers

Collor is not a physical property of matter

I WILL MARK BRAINIEST

Answers

Answer:

i think answer b

Explanation:

Two positively charged particles are 0.03 m apart. The first particle has a
charge of 8.1 C, and the second a charge of 2.6 C. Which change would
increase the electric force between the two particles?

Answers

Answer:1.3  103 N

Explanation:hope this helps.

Increasing the charge on each particle by 2.0C would increase the electric force between the two particles. Therefore, option (B) is correct.

What is coulomb's law?

According to Coulomb’s law, the force between two charged point charges is the product of the magnitude of their charges and is inversely proportional to the square of the distance between the point charges. This force usually acts along the line which is joining the two charges.

The magnitude of the electric force can be expressed mathematically:

[tex]F = k\frac{q_1q_2}{r^2}[/tex]

where k is constant and has a value of 8.99 × 10⁹ N.m²/C².

We have given the two-point charges 8.1 C and 2.6 C. The distance between them is equal to 0.03 m. From the above-written formula, we can say that the charge on the particles is directly proportional to the electric force, and the distance between the charged particles is inversely proportional to the electric force.

Therefore, increasing the charge on each particle by 2.0 C would increase the electric force between the two particles.

Learn more about Coulomb's law, here:

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If you fire a gun horizontally, and at the same time drop a bullet/slug from the same height, what will happen?

Answers

Answer:

There you have it. The y-component of air resistance for the fired bullet still depends on the fired speed of the bullet (since it is proportional to v2). A fired bullet (with air resistance) does not hit the ground at the same time as a dropped bullet.

Explanation:

hope this helped ✨

A man is riding his 4-wheeler at 60 km/hr. If he is riding it constantly at
this rate for 1.5 hours, how far did he ride?

Answers

Answer: 90 km

Explanation: 60 * 1.5

what do waves create

Answers

Answer:

Waves transmit energy, not water, and are commonly caused by the wind as it blows across the ocean, lakes, and rivers. Waves caused by the gravitational pull of the moon and the sun are called tides.

Explanation:

Answer:

Waves are created by energy passing through water, causing it to move in a circular motion. However, water does not actually travel in waves. Waves transmit energy, not water, across the ocean and if not obstructed by anything, they have the potential to travel across an entire ocean basin. Waves are most commonly caused by wind. I hope this helped!

The speed of an object changes only when it is acted on by an unbalanced force.

Answers

Answer:

If an object has a net force acting on it, it will accelerate. The object will speed up, slow down or change direction. An unbalanced force (net force) acting on an object changes its speed and/or direction of motion. An unbalanced force is an unopposed force that causes a change in motion.

Explanation:

I hope this helps you out and if your feeling generous plz mark brainliest it helps me a lot thank you:)

Two asteroids with masses 5.34 x 108 kg and 2.06 x 104 kg are separated by a distance of 5,000 m. What is the gravitational force between the asteroids? Newton's law of gravitation is F. Gm}m2. The gravitational constant gravity Gis 6.67 x 10-11 N.m²/kg². A. 1.47 x 10-⁶N
B. 4.00 N
C. 1.24 x 10³³ N
D. 2.93 x 10-¹⁰N​

Answers

Answer: D

Explanation: just completed this question on a p e x

5. An ion consist of 12 electrons and 11 proton. What is the charge
on the ion?

Answers

Answer:

-1

Explanation:

Electrons have a negative charge and protons have a positive charge. (+11) + (-12) = -1

A baseball is hit into the air with a velocity of 27 m/s. How high does it go?

Answers

Answer:

Explanation:

If a baseball is hit into the air with a velocity of 27 m/s, we want to determine the maximum height of the ball. Using the projecile formula;

Max height H = u²/2g

u is the initial velocity of the body = 27m/s

g is the acceleration due to gravity = 9.81m/s²

H = 27²/2(9.81)

H = 729/19.62

H = 37.16m

Hence the ball went 37.16m high

List some factors that would affect the speed of the car.​

Answers

Answer:

The power of the car, the gear ratio, weight of the car, aerodynamics of the car, grip of the tires on the road, calorific value of the fuel used, and friction would affect the speed of the car.

What was the main aim behind Wegener's continental drift theory?
A. To explain major climate changes
B. To explain geological similarities
C.to explain landforms of area
D. All of the above

Answers

d.all of the above is the answer for this question

A piece of copper with a volume of 100cm3 has a mass of 890 g. Explain how you could use this information to find out how much mass would be in 13cm3 of copper.


plz help this q. is due today

Answers

Answer:

115.7g

Explanation:

Given parameters:

    Volume of copper  = 100cm³

    Mass of copper  = 890g

Unknown:

Mass of 13cm³ copper  = ?

Solution:

We know that the two materials are both made up of copper. Since we know the mass and volume of the first one, let us solve for the density. Using the density of the first one, we can determine the mass of the second one by the given volume.

Density is an intrinsic property of matter. It has the same value for every given substance.

It is expressed as mass per volume of  a substance;

    Density  = [tex]\frac{mass}{volume}[/tex]

Input the parameters and solve;

  Density  = [tex]\frac{890}{100}[/tex]  = 8.9g/cm³

Now to find the mass of the 13cm³ copper;

       Mass  = density x volume

       Mass  = 8.9 x 13  = 115.7g

Patty decides to try another experiment. From the
same branch, she drops a large, heavy rock and a
small pebble. What would happen this time?

Answers

Answer: They will fall at the same time

Explanation:I had a google doc about this

When air resistance is considered, the effect of the air resistance will cause the rock to fall faster than the pebble which will be delayed due to its lesser weight. In the absence of air resistance, both rock and pebble will fall down at the same time.

What are free fall and air resistance?

Free fall is a motion of an object in which the force of gravity is the only force acting upon it. A body moving upwards would not be considered to be falling. But if the body falls under the effect of the force of gravity, it is said to be in free fall.

Free fall is a type of motion in which no air resistance is considered and the force acting upon an object is only gravity. All bodies under such conditions fall with an equal rate of acceleration, regardless of their masses.

As a body falls through the air, have suffered some degree of air resistance. Air resistance is the collisions of the surface of an object with molecules present in the air. The factors that have a direct effect on the amount of air resistance are the cross-sectional area and the speed of the object.

As the rock had greater weight than the pebble in the absence of air resistance it will fall faster than the pebble.

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Which of the following is not a property of electromagnetic waves?

Answers

Answer: It does not include alpha rays

Explanation: It does not include alpha rays

Why is the nucleus positive in charge?

Answers

Answer:

The nucleus has an overall positive charge as it contains the protons. Every atom has no overall charge (neutral). This is because they contain equal numbers of positive protons and negative electrons. These opposite charges cancel each other out making the atom neutral.

Explanation:

Select the correct words from the drop-down menus to complete the sentence.
The
v work of a machine can never exceed the
work because
some of the work.
uses

Answers

Answer:

1. C

2. B

3. B

Explanation:

Took assignment on edge

The

YO CAN YALL HELP ME IN DIS!

Answers

Answer:

i guess it will be mass or volume, but not sure

Explanation:

because the blocks volume will be same as the displaced water, then u will check the mass or volume of the water to see what the volume of a object will be.

A ball is thrown upwards into the air with an initial velocity of
17.5 m/s. What is the maximum height that the ball traveled
during that time (assuming there is no air resistance). Round your
answer to two decimals places.

Answers

Answer:

y = 15.61 [m]

Explanation:

To solve this problem we must use the following kinematics equation. We must bear in mind that the acceleration of gravity is negative since the direction of gravity is opposite to the direction of motion.

[tex]v_{f} ^{2} = v_{i} ^{2} -(2*g*y)[/tex]

where:

Vf = final velocity = 0

Vi = initial velocity = 17.5 [m/s]

g = gravity acceleration = 9.81 [m/s^2]

y = height [m]

The final speed is zero, since the ball reaches the maximum height its speed will be zero since it cannot be lifted up more.

0 = (17.5)^2 - (2*9.81*y)

306.25 = 2*9.81*y

y = 15.61 [m]

2. The Himalayas in central Asia are the tallest mountains in the world. But fossils of seashells can be found high in these mountains, far from any ocean.
How do you think they got there?

Answers

Answer:

The sea level could have been much higher in the past.

Explanation:

The tectonic plates shifted and the mountain rose from there.

They are trapped throughout the rock whereas the seashells have been on the floor of a modest seafloor.

These same containers dropped down on the base of the silt level or sheet, as well as those layering finally became rock.Few more million generations previously, the Indian civilization or the subcontinent crashed well with the continents of Asia, making the Himalayan mountains rock which thus previously were such a sea level.

Thus the above response is appropriate.

Learn more about the Himalayan mountains here:

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A ball is thrown vertically down from the edge of a cliff with a speed of 4 m/s,
how high is the cliff, if it took 12 s for the ball to reach the ground?

Answers

By using the equation speed = distance/time we can solve for distance. The speed is 4 m/s and the time is 12 seconds. We need to rearrange the equation to Speed * Time = distance. 4(12) = 48; 48 = distance. The cliff is 48 meters high.

a car with a mass of 1,100 kg is moving down the highway with an applied force (force of the engine) of 2,450 N and a friction force of 825 N. What is the cars acceleration

Answers

Explanation:

2.23 m/s^2 squared yung 2

A drug like cocaine causes more dopamine to be produced in the brain.


Please select the best answer from the choices provided

T
F

Answers

Answer:

True

Explanation:

A drug like cocaine causes more dopamine to be produced in the brain is True.

What is Dopamine?

Dopamine is a type of neurotransmitter which can be a monoamine. This dopamine will be produced in brain and it acts as a chemical messenger which will be used to communicate messages between the nerve cells in the brain and to the brain and the other parts of the body.

When an individual who takes the drugs such as heroin, nicotine, cocaine and methamphetamine can increases or promotes the neurochemical reaction which will produce or increases the amount of dopamine that is a primary factor which can be the addiction that is secreted by neurons in the brain's reward center.

The functions of the reward center is memory, movement, motivation, mood, attention and more.

The diseases caused by dopamine are higher dopamine levels lead to pleasure in the mind of an addict and it makes people forget the pain or stress and gives immense pleasure.

To know more about dopamine,

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