A rock is dropped (from rest) off a bridge over the Merrimack River. The falling rock
accelerates at 10 m/s2 downward. If it takes 2.5 seconds before a splash is heard,
approximately how high is the bridge?

Answers

Answer 1

Answer:

31.25 meters or ~31 meters approximately

Explanation:

Let's see which of the 5 variables we are given since this is a constant acceleration problem.

[tex]v_i \ \ \ \ \ \ t \\ v_f \ \ \ \ \ \triangle x \\ a[/tex]

We want to find the height of the bridge, aka the vertical displacement of the rock. Let's set the upwards direction to be positive and the downwards direction to be negative.

We are told that the acceleration is 10 m/s² downward, so we have a = -10 m/s².

We are also told that the time it takes the rock to hit the water is 2.5 seconds. Time is the same regardless of the x- or y- direction, so we can say that t = 2.5 seconds.

Now, we aren't told this directly, but we can figure out that the velocity in the y-direction is 0 m/s, since the rock is dropped from rest off the bridge. Therefore, [tex]v_i=0 \frac{m}{s}[/tex].

We want to find the vertical displacement, the height of the bridge, so we can say that [tex]\triangle x= \ ?[/tex]

We have 4 out of 5 variables:

[tex]v_i,\ a, \ t, \ \triangle x[/tex]

Look through the constant acceleration equations to see which equation has all 4 of these variables. You should come up with this one (no final velocity):

[tex]x_f=x_i+v_it+\frac{1}{2}at^2[/tex]

Subtract [tex]x_i[/tex] from both sides of the equation to get:

[tex]\triangle x=v_it+\frac{1}{2}at^2[/tex]

Substitute in our known variables and solve for delta x.

[tex]\triangle x=(0\frac{m}{s})(2.5s) + \frac{1}{2} (-10\frac{m}{s^2})(2.5s)^2[/tex]

0 m/s multiplied by 2.5 s is 0, so we have:

[tex]\triangle x =\frac{1}{2} (-10)(2.5)^2[/tex]

Evaluate the exponent first and multiply the terms together.

[tex]\triangle x =(-5)(6.25)[/tex] [tex]\triangle x =-31.25[/tex]

The vertical displacement is -31.25 meters from the rock's starting position, so we can say that the height of the bridge is 31.25 meters, which is approximately 31 meters tall.

Answer 2

Answer:

31 meters

hope it help you

thanks for free points.........


Related Questions

Please view image attached!

Answers

Answer:

you would expect a change in the graph

Explanation:

A car of mass 1470 kg is on an icy driveway
inclined at an angle of 40◦. The acceleration of gravity is 9.8 m.
If the incline is frictionless, what is the acceleration of the car Answer in units of m/s

Answers

Answer:

  a = 7.5 m / s²

Explanation:

For this exercise let's use Newton's second law, let's create a coordinate system with the x axis parallel to the plane and the y axis perpendicular to the plane

Y axis

       N - W cos θ = 0

       N = mg cos θ

X axis

       W sin θ = m a

 

       mg sin θ = m a

        a = g sin θ

let's calculate

        a = 9.8 cos 40

        a = 7.5 m / s²

What are the ways of heat transfer?

Answers

Answer:

Conduction, Convection and Radiation

Explanation:

Hope this helps!

Conduction radiation and convection

what are insulators of electricity​

Answers

Answer:

Rubber

Glass

Pure water

Oil

Air

Diamond

Dry wood

Dry cotton

Plastic

Asphalt

Other strong insulators include:

Fiberglass

Dry paper

Porcelain

Ceramics

Quartz

Explanation:

I hope this helps

In which of the following instrument is the image that is formed erect
a. Pin hole camera b. Simple camera c. microscope d. periscope​

Answers

Answer:

C. microscope

Explanation:

A simple microscope is magnifying glass, an ordinary double convex lens having a short focal length that produces virtual and erect image.

what is the motion of a car​

Answers

Answer: Assuming you are driving a car on the road, consider the motion of the car. As the wheels of the car spin backwards, they push the road backwards. In consequence, the road must push the wheels forward according to the third law of motion. It is this reaction force acting on the wheels causes the car to move forward.

Explanation: hope this helps!

define the unit of time and unit of length​

Answers

This is your perfect answer

The base unit for time is the second (the other SI units are: metre for length, kilogram for mass, ampere for electric current, kelvin for temperature, candela for luminous intensity, and mole for the amount of substance). The second can be abbreviated as s or sec.

Answer:

hope you like

Explanation:

A unit of time is any particular time interval, used as a standard way of measuring or expressing duration.Its SI unit is second

A unit of length refers to any arbitrarily chosen and accepted reference standard for measurement of length. Its SI unit is meter

A cow standing atop a building in Times Square recalled a funny joke and began to laugh. The uncontrollable laughter caused the cow to fall over the side of the building. He fell for a time period of 3.5 s and landed in a bed of bushes. How fast was the cow moo-ving when he reached the bushes?

Which equation should be used to solve the problem?

Answers

Answer:

Vf = 34.3 m/s

1st equation of motion was used to solve.

Explanation:

In order to find the final speed of the cow, when it hits the bushes, we can use first equation of motion:

Vf = Vi + gt

where,

Vf = Final Velocity of Cow = ?

Vi = Initial Velocity of Cow = 0 m/s

g = acceleration due to gravity = 9.8 m/s²

t = time taken = 3.5 s

Therefore,

Vf = 0 m/s + (9.8 m/s²)(3.5 s)

Vf = 34.3 m/s

1st equation of motion was used to solve.

Randy has 2 cats. The male is solid black. The female is white. The cats have 6 kittens. All the kittens are black.
What does this tell Randy?
A. Black fur color may be a dominant trait.
Ooo
B. Fur color is passed on by one parent.
C. Fur color is random in cats.
D. The color of the parents does not affect the kittens.
E. Kitten fur color changes.

Answers

B fur is passed on by one parent

Here, the black color may be dominant trait in the kittens  and trait for white color is hidden in the kittens.

What are genetic traits ?

The genetic codes that creates a particular characteristics in a species is called a gene trait.  Most of common characteristics will be inherited from the parents to the offsprings.

The B gene regulates the synthesis of eumelanin, the pigment that gives cats their black fur. It has three different alleles, or kinds. It just takes one B allele from one parent for a cat to have black fur since the B gene, which causes black fur, is dominant.

Either parent's color or a mixed color is getting for the kittens. Sometimes the one color trait will be hidden in them and in that case they show the color one parent that is dominant.

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A sound wave is an example of a __________ wave. It requires a _________ to transfer energy.



Question 3 options:

medium, transverse


transverse, medium


longitudinal , medium


medium, longitudinal

Answers

Answer:

its A

Explanation:

An egg is thrown horizontally off the top row bleachers at the Brickyard,
which is 30 meters high, with a horizontal velocity of 7.5 m/s. How long
does it take to hit the ground?

Answers

Answer:

4

Explanation:

Divide 30 meters by 7.5 and you´re answer is 4. This is how I would think you solve the problem

Just wondering, what do you guys think the 5th dimension is? I've always believed it to be light.

Answers

Answer: In the 5th dimension, they who claim to know, say that there is only one time, including the past and the future.

Find the momentum of a 23.1 g bullet fired at 621 m/s.
a. 1.43×104 Ns
b. 26.9Ns
c. 2.69×10–2Ns
d. 14.3Ns

Answers

Answer:

d. 14.3 Ns

Explanation:

Mass of the bullet (m) = 23.1 g = 0.0231 kg

Speed of the bullet (v) = 621 m/s

Momentum (p) is measured as the product of mass of the body and it's speed.

Mathematical Representation/Equation of Momentum:

[tex] \boxed{ \bf{p = mv}} [/tex]

By using equation of momentum, we get:

[tex]\rm \longrightarrow p = 0.0231 \times 621 \\ \\ \rm \longrightarrow p = 14.3 \: kg \: m {s}^{ - 1} \\ \\ \rm \longrightarrow p = 14.3 \: Ns[/tex]

The momentum of a 23.1g bullet fired at 621 m/s is 14.3Ns.

HOW TO CALCULATE MOMENTUM:

Momentum is a product of an object's mass and velocity. That is, it can be calculated as follows:

Momentum (p) = mass (m) × velocity (v)

According to this question, a 23.1g bullet is fired at 621m/s. The momentum can be calculated thus:

Mass of bullet in kg = 23.1/1000 = 0.00231kg

Momentum (p) = 0.00231kg × 621m/s

Momentum = 14.34Ns

Therefore, the momentum of a 23.1g bullet fired at 621 m/s is 14.3Ns.

Learn more about momentum at: https://brainly.com/question/20301772?referrer=searchResults


If Judy walks 2 blocks north, 5 blocks west, and then 2 blocks south, what is her final
displacement?

Answers

Answer: 2 blocks east if i'm not mistaken.

Rachel is feeling ill. Which symptom indicates that Rachel's illness is related to her ear and that she should consult a doctor? tooth sensitivity neck or jaw pain sensitivity to light loss of balance

Answers

Answer:

light loss of balance

Explanation:

it makes the person who is ill unstable

Light loss of balance symptom indicates that Rachel's illness is related to her ear and that she should consult a doctor.

What are the symptoms of illness related to ear?

A physical or psychological issue that a person has that could be a sign of an illness or condition is known as symptom. Symptoms are invisible and do not appear on diagnostic tests.

symptoms of illness related to ear in child  include:

ache in the ears, particularly when sleeping downgrabbing an ear or pulling itdifficulty sleeping excessive cryingFussinessdifficulty hearing or recognizing soundsloss of balancea fever of at least 100 F (38 C).fluid coming out of the earHeadachereduced appetite

Adults typically exhibit the following signs and symptoms in illness related to ear:

ear discomfortan ear infection fluid drainage hearing issues

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PLEASE HELP!! ITS URGENT!!!​

Answers

Answer:

F = 800 [N]

Explanation:

To be able to calculate this problem we must use the principle of momentum before and after the impact of the hammer.

We must summarize that after the impact the hammer does not move, therefore its speed is zero. In this way, we can propose the following equation.

ΣPbefore = ΣPafter

[tex](m_{1}*v_{1}) - F*t = (m_{1}*v_{2})[/tex]

where:

m₁ = mass of the hammer = 0.15 [m/s]

v₁ = velocity of the hammer = 8 [m/s]

F = force [N] (units of Newtons)

t = time = 0.0015 [s]

v₂ = velocity of the hammer after the impact = 0

[tex](0.15*8)-(F*0.0015) = (0.15*0)\\F*0.0015 = 0.15*8\\F = 1.2/(0.0015)\\F = 800 [N][/tex]

Note: The force is taken as negative since it is exerted by the nail on the hammer and this force is directed in the opposite direction to the movement of the hammer.

If you maintain a constant force on an object what happens to the acceleration? What happens to the
velocity?

Answers

Answer:

Because you have no force, the acceleration is zero and the body moves at a constant speed

the acceleration is 0 and the body moves at a constant speed

A student is building a model of a parallel circuit consisting of a battery, a switch, five light bulbs, and wires. When she connects all of the
components of her model, none of the bulbs light up. Which of the following could be the problem with her model? (AKS 10b / DOK 2)
1
2
3
4
One of the bulbs is burnt
out
One or more of the wires is not connected to the battery
The switch isn't properly closed
The resistance of the light bulbs prevents current from flowing through the circuit
O A 1, 2, and 4
OB 1, 2, and 3
OC. 1, 3, and 4
OD. 2, 3, and 4

Answers

Answer:

(D) 2, 3, and 4

Explanation:

Given that the connection is parallel,

The parallel circuit consisting of a battery, a switch, wires, and 5 bulbs has been shown in the figure.

But none of the bulbs light up upon completing the connection.

The given possible reasons are:

Option (1): One of the bulbs is burnt out.

As the connection is parallel, so the current from the battery is divided to all 5 bulbs, is one bulb is burnt out, it will not stop the current flowing through the other bulbs, so this is not the possible reason.

Option (2): One or more of the wires is not connected to the battery.

If one or more wire is not connected to the battery, then there will be no current in the circuit, so, no bulb will glow. Hence this may be the possible reason.

Option (3): The switch isn't properly closed.

If the switch isn't properly closed, then the circuit is not closed. Then there will be no current in the circuit, so, no bulb will glow. Hence this may be the possible reason.

Option (4): The resistance of the light bulbs prevents current from flowing through the circuit.

If the resistance of the bulb is very large and the current flowing in it is too less, then there will not be sufficient to glow the bulb. so, no bulb will glow. Hence this may be the possible reason.

So, the possible may be options (2), (3), and (4).

Hence, option (D) is correct.

I will give 14 points & make you the brainiest
Terrestrial planets are primarily composed of what two materials?

a. hydrogen and helium

b. silicate rocks and metals

c. frozen water and methane

d. helium and iron

Answers

Answer:

B. silicate rocks and metals

Terrestrial planets, such as Earth, are primarily composed of silicate rocks and metals. The correct answer is b. silicate rocks and metals.

Silicate rocks, which are made up of silicon and oxygen, are the dominant building blocks of these planets. They include minerals like quartz, feldspar, and mica. Terrestrial planets contain significant amounts of metals such as iron, nickel, and other heavy elements. These metals are found in the planet's core, providing structural strength and contributing to the planet's magnetic field.

This composition differentiates terrestrial planets from gas giants like Jupiter and Saturn, which are predominantly composed of hydrogen and helium. The combination of silicate rocks and metals forms the solid, rocky surfaces that characterize terrestrial planets.

Therefore, The correct answer is b. silicate rocks and metals.

For more details regarding terrestrial planets, visit:

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Which of the following yoga poses is a good pose to help you practice proper posture? A. Triangle pose B. Mountain pose C. Warrior II pose D. Seated Wide-leg saddle

Answers

Answer:B. Mountain Pose

Explanation:

An ice skater spins with an angular speed 2w with an angular speed

Answers

Anwser

It decreases The factor of two.

Step by step explanation

If she spin at a angular speed of 2w, and an initial speed of fi, when she slows down she is only has a angular speed of W, meaning that decreased 2

PS the anwser above me is wrong because in the question it said she decree so I couldn’t have stayed the same.

Hope this helps!

3
A comb is charged negatively when coming a dry hair
is there a tranfer of charge alone or mass also

Answers

Answer:

there is transfer of change alone

Answer:

someone pls explain this question

A resultant force of 4 N acts on a object of mass 0.50 kg for 3 seconds. What is the change in velocity caused by this force?
A- 4 m/s
B- 6 m/s
C- 12 m/s
D- 24 m/s
It’s D but why?

Answers

Answer:24

Explanation:

First you need to calculate the acceleration, for this use can use the following formula Force (F) = Mass (M) x Acceleration (A). If we extract A out of this, you can get the following equation A = F/M = 4/0.5 = 8 m/s^2. So, the object accelerates each second by 8 m/s, if the object does this for 3 second, the velocity would be 8 x 3 = 24

What does the big ‘2’ in 2CO2 mean?



Please help quickly i'm in science class

Answers

Answer:

It means you multiply everything after the "Big two"

Explanation:

How to Calculate weight

Answers

Answer:

Weight is a measure of the force of gravity pulling down on an object. It depends on the object's mass and the acceleration due to gravity, which is 9.8 m/s2 on Earth. The formula for calculating weight is F = m × 9.8 m/s2, where F is the object's weight in Newtons (N) and m is the object's mass in kilograms.

Explanation:

How much power is required to lift a 2.00-kg object 5.00 meters in 4.50 seconds? (If there is a formula for this please, tell me what it is also it is about pulleys one of the simple machines)

Answers

Power = w/t
W=mgh
W=2*9.8*5=98 j
Power = 98/4.5
Power = 21.7 watt

The sum of two component vectors is referred to as the
vector.
Addition
Quantitative
Subtraction
Resultant

Answers

resultant is the correct answer!

State the career function of chemical engineering​

Answers

Answer:

Chemical engineers develop and design chemical manufacturing processes. They apply the principles of chemistry, biology, physics, and math to answer problems that involve the production of chemicals, fuel, drugs, food, and many products

Explanation:

Answer:

The main role of chemical engineers is to design and troubleshoot processes for the production of chemicals, fuels, foods, pharmaceuticals, and biologicals, just to name a few. They are most often employed by large-scale manufacturing plants to maximize productivity and product quality while minimizing costs

Explanation:

Match the letter to the appropriate name of the variable

Answers

Based off what tho ?

Answer: yes

Explanation:

What phrase would a Patriot who SUPPORTED independence from Britain agree
with?
A "No taxation without representation"
B "No war is worth its cost in life"
C "Loyalty to the British at all costs"
D "Let us not pay a price in blood but instead accept the dove of peace"

Answers

The correct answer is A
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