A bridge is constructed above a river such that an object dropped from it will reach the river after 4.5 seconds. A precocious youth takes a small stone and throws it downwards with some negative inital velocity so that it hits the river afer only 3 seconds. With what final velocity will the thrown stone hit the water?

Answers

Answer 1

Answer:

Vf = 11.04 m/s

Explanation:

First, we consider free fall motion with zero initial velocity. Using 2nd equation of motion:

h = Vi t + (1/2)gt²

where,

h = height of bridge = ?

Vi = Initial  Speed  = 0 m/s

t = time taken = 4.5 s

g = 9.8 m/s²

Therefore,

h = (0 m/s)(4.5 s) + (1/2)(9.8 m/s²)(4.5 s)²

Therefore,

h = 99.225 m

Now, we consider the forced motion when the youth throws the ball with some negative initial energy:

Vi = - Vi

t = 3 s

h = 99.225 m

Therefore,

99.225 m = - Vi(3 s) + (1/2)(9.8 m/s²)(3 s)²

Vi = (- 99.225 m + 44.145 m)/3 s

Vi = - 18.36 m/s

Now, we use this in 1st equation of motion for final velocity:

Vf = Vi + gt

Vf = -18.36 m/s + (9.8 m/s²)(3 s)

Therefore,

Vf = 11.04 m/s


Related Questions

Radio stations broadcast signals on two different frequency bands. These are called

Answers

Answer:

AM(amplitude modulation) and FM(frequency modulation)

Explanation:

A radio frequency band is a small adjacent section of the radio spectrum frequencies, whereby channels are usually used or set aside to be used.

They are usually of two different bands called AM which is known as amplitude modulation and FM which is known as frequency modulation

If you are in a car at a stop sign and then the driver
presses on the gas pedal really hard, which way is the car
accelerating?

Answers

Answer:

it wont be because the hand brake would be on

The car is accelerating forward.

NEED HELP IS THERE SOMEONE CAN HELP ME PLS :)

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if you climb the hill you will be tired also it will be 4.00 meters per second

Name all errors and type it again
EZ POINTS CMON

Answers

Answer:

you need to capitalize

Explanation:

When Grandpa Joe comes to visit, he tells us stories about when he was in the army with Colonel Jack S. Anderson.

Which TWO correctly relate the attraction between the particles of a liquid and the temperature at which the liquid changes state?

A. Strong attractions mean the liquid melts at a higher temperature
B. Strong attractions mean the liquid melts at a lower temperature
C. Strong attractions mean the liquid boils at a higher temperature
D. Strong attractions mean the liquid boils at a lower temperature

Answers

Answer:

a &c

Explanation:

>3

Attraction between the molecules of a liquid and the temperature at which the liquid changes state is "Strong attractions mean the liquid boils at a higher temperature". The correct option is C

What is Temperature ?

Temperature is a physical quantity which measures hotness and coldness of a body. Temperature measures the degree of vibration of molecule in a body. Temperature is measured in centigrade (°C), Fahrenheit (°F) and Kelvin (K) in which Kelvin (K) is a SI unit of temperature. Absolute scale of temperature means Kelvin scale of temperature.

relation between Kelvin(K) and centigrade (°C),

°C= K - 273.15

from equation, 273.15 K means 0 °C, which is freezing point of water (ice).

when we give temperature to the body, its molecule or atom absorbs thermal energy and vibrate about their mean position. Amplitude of vibration get increases as we go on increasing temperature and for higher temperature force of attraction between molecules gets weaker. Hence for higher temperature, due to weaken the force of attraction between molecule, solid goes into liquid state. and further increase in temperature liquid goes into gaseous state.

Liquid has stronger force of attraction than gas and weaker than solid. Strong force of attraction means high temperature should be given to break molecular bonds. Therefore Strong attractions mean the liquid boils at a higher temperature.

Hence option C is correct.

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You are making s'mores with a friend. When you heat the marshmallow over the fire, what happens to the volume of the air bubbles inside the marshmallows? *

Answers

Answer:

Heat was trapped within the marshmallow.

Explanation:

Increasing temperatures make air contained within the marshmallow extend to fill up more room, causing the versatile sugar combination to spread. Eventually, if there is so much tension? It's small explosion. But take the marshmallow out from the heat, and it's going to deflate even if the extended gelatin does not really recover quickly.

Answer:

Heat gets trapped within the marshmallow.

Explanation:

Can you hear sounds from space or not? Why or Why not?

Answers

Answer: NO

Step by step explanation: No you cannot hear sounds from space, sound travels though the vibrations of Atoms and molecules so in space there is no air, so sound would have no way to travel....

What are greenhouse gases? Can you name any?

Answers

greenhouse gasses in the upper atmosphere trap heat from the Earth and reflect it back down rather than allow it to escape. This makes Earth progressively warmer.

A generator converts mechanical energy to electrical energy by using a conducting metal loop turning in a...
A. magnetic field
B. Gravitational field
C. Steel sphere
D. Cooper sphere

Answers

Answer:

B- Gravitational Field

Explanation:

Have a nice day, hope you get a good grade!

The  generator converts mechanical energy to electrical energy by using a conducting metal loop turning in a gravitational field.

What is the gravitational field?

In terms of physics, a gravitational field represent the model that should be used for explaining the impact where the massive body should be extended into the space around it. Also, generating the force on the another massive body.

Therefore, based on the above explanation, the correct option is b.

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A satellite was in two separate crashes. In both crashes, the satellite had the same mass. Engineers want to know about the speed and direction of the satellite after the crashes. Why would the crash affect the motion of the satellite, and which crash caused a greater change in motion for the satellite?

Answers

Answer & Explanation:

Crashing into the asteroid would cause the satellite to slow down, stop, or reverse direction, because it is a force in the opposite direction to the satellite's motion. Whichever crash was a stronger force would cause it to change motion more. It takes a stronger force to change the velocity of a more massive object.

A rocket, initially at rest on the ground, accelerates straight upward from rest with constant (net) acceleration 53.9 m/s2 . The acceleration period lasts for time 6.00 s until the fuel is exhausted. After that, the rocket is in free fall.

Find the maximum height ymax reached by the rocket. Ignore air resistance and assume a constant free-fall acceleration equal to 9.80 m/s2 .

Answers

Answer:

maximum height reach by rockect =970.2metre

Explanation:

find acceleration of block and tension in strings if m1 =8kg m2= 4kg and take g=10m/s²​

Answers

[tex]\large\bold{\underline{\underline{Given:-}}}[/tex]

[tex]\sf{m_1}[/tex] = 8kg

[tex]\sf{m_2}[/tex] = 4kg

g = 10m/s²

[tex]\large\bold{\underline{\underline{To \: Find:-}}}[/tex]

→Acceleration of block

→Tension in strings

[tex]\large\bold{\underline{\underline{Solution:-}}}[/tex]

Let, the two equation will be ,

[tex]\leadsto[/tex] 8g - T = 8a ..... Equation no (1)

[tex]\leadsto[/tex] T - 4g = 4a ..... Equation no (2)

Putting the value of equation no (1) and (2) we get,

[tex]\implies[/tex] 4g = 12a

[tex]\implies[/tex] 4 × 10 = 12a

[tex]\implies[/tex] 40 = 12a

[tex]\implies[/tex] a = [tex]\sf\dfrac{\cancel{40}}{\cancel{12}}[/tex]

[tex]\dashrightarrow[/tex] a = [tex]\dfrac{10}{3}[/tex]

Again, we have to putting the value of a in the equation no (2) we get,

[tex]\implies[/tex] T - 4g = 4 × [tex]\dfrac{10}{3}[/tex]

[tex]\implies[/tex] T - 4 × 10 = 4 × [tex]\dfrac{10}{3}[/tex]

[tex]\implies[/tex] T - 40 = [tex]\dfrac{40}{3}[/tex]

[tex]\implies[/tex] T = [tex]\dfrac{40}{3}[/tex] + 40

[tex]\implies[/tex] T = [tex]\dfrac{40 + 120}{3}[/tex]

[tex]\dashrightarrow[/tex] T = [tex]\dfrac{160}{3}[/tex] N

[tex]\therefore[/tex] Acceleration of block = [tex]\dfrac{10}{3}[/tex] m/s².

And, Tension in strings = [tex]\dfrac{160}{3}[/tex] N

A fire is burning in a fireplace. Where is the radiation?

A. You touch warm bricks next to the fireplace
B. You can feel the heat from across the room
C. Heat is rising up from the chimney

Answers

I think it’s A.
........

What is one physical benefit that can be obtained from participating in field events?

A) strengthen balance
B) better sleep pattern
C) increase capacity for learning
D) all of the above

Answers

Answer:

D

Explanation:

It does all three

A stunt man launches a car from the edge of a cliff horizontally. If he is launching off a
30-meter high cliff and must hit a mark 268-meters down range, with what speed
must he leave the cliff?

Answers

Answer:

All i got to say is that he is dead dead

Explanation:

You push against a wall and the wall pushes back on you.
O Newton's 1st Law of Motion
O Newton's 2nd Law of Motion
Newton's 3rd Law of Motion

Answers

Answer:

Its the third law of motion.

Explanation:

Newton's third law of motion states that every action has equal and opposite reaction.

Jen had an average speed of 2.5 m/s when hopping on one foot. If she hopped for 5.0 seconds, for what distance was she hopping?

Answers

Explanation:

distance

speed =_________

time

distance = speed × time

= 2.5 × 5.0

distance = 12.5 m

What tool of dream analysis says that feelings and urges are hidden inside an event? condensation symbolism projection displacement

Answers

Answer:

Condensation

Explanation:

Answer:

Condensation! Hope this helps!!!

Explanation:

Scientists have invented the equipment to harness the power of lighting for energy use. True or false

Answers

I think it’s false .
Let me know if it’s incorrect .

Tyler drives 50km north. Tyler then drives back 30km south. What distance did he cover? What was his displacement?

Answers

Answer:

80 km is distance and 30km north is displacement

Explanation:

distance= 50+30=80km

displacement= 50-20=30

his displacement is 30km north

When Tyler drives 50 km north and then drives back 30 km south, we have:

1. The distance that he covers is 80 km.

2. Tylor's displacement is 20 km.  

1. The distance is a scalar that is given by the sum of the kilometers traveled by Tyler as follows:

[tex] d = d_{1} + d_{2} = 50 km + 30 km = 80 km [/tex]

Hence, the distance traveled by Tyler was 80 km.

2. The displacement is a vector that depends on the direction of travel. Takin the north direction as positive we have:

[tex] x = x_{1} + x_{2} = 50 km + (-30 km) = 20 km [/tex]

Therefore, Tyler's displacement is 20 km.

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A 30 kg object has a frictional force of 60 N. It's coefficient of friction must be...?
A) 0.2
B) 2
C) .002
D) 20

Answers

mass = 30kg

frictional force = coefficient of friction * (mass * g)

g = 9.8 m/s^2

So:

60N = x * 294 N

x = 60 N / 294 N = 0,2

When the energy of a wave increases, what happens to the amplitude?

Answers

Answer:

The energy transported by a wave is directly proportional to the square of the amplitude. So whatever change occurs in the amplitude, the square of that effect impacts the energy. This means that a doubling of the amplitude results in a quadrupling of the energy.

Explanation:

When the energy of a wave increases, the amplitude also increases. This is because the amplitude of the wave is directly proportional to the energy of a wave.

What is the amplitude of a wave?

The amplitude of a wave may be defined as the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. It is equal to one-half the length of the vibration path.

It is the principle of physics that when the amplitude of the wave is higher, the energy also gets higher. To summarise, waves carry energy. The amount of energy they carry is related to their frequency and their amplitude. The higher the frequency, the more energy, and the higher the amplitude, the more energy.

Therefore, when the energy of a wave increases, the amplitude also increases. This is because the amplitude of the wave is directly proportional to the energy of a wave.

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please help!!! give me a summary on why human population is either good or bad!! thank youu

Answers

It is bad because humans are destroying the planet with pollution and cutting down natural habitats. This is not only killing the human population in the future, but as of right now they are killing animals, and trees. The human population is slowly destroying the planet.

to calculatw the power produced by a force, the size of the force must be known. What else needs to be known to calculate the power

Answers

-- The distance the force moved through

-- How long the force lasted

The other thing we need to calculate the power is the "Velocity".

A quantity of labor or work done to be accomplished within a particular period of timeframe is determined as power. It is denoted by "P".According to the given query, we are talking about the relation between Power and Force. Along with simple instances where such an item is moved at continuous speed by a constant force.

The relation can be shown as:

→ [tex]P= Fv[/tex]

where,

P = PowerF = Forcev = Velocity

Thus the above is the right response.

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Ashley is flying a plane that has to reach a gradient of 360m/km in order to take off and not crash. Her goal is to travel from sea level to an elevation of 1000m at a distance of 2.8km. Calculate the gradient of Ashley’s flight and determine if she will crash!

Answers

Answer:

She is likely to crash because her flight gradient is lesser than the flight gradient required gradient to avoid crashing

Explanation:

The given parameters are;

The required gradient of the plane Ashley is flying needs to reach in order to take off and not crash = 360 m/km

The initial elevation of the plane Ashley is flying = Sea level = 0 m

The goal Ashley intends to make = Elevation of 1000 m at 2.8 km. distance

∴ Ashley's goal = Traveling from sea level to 1000 m at 2.8 km horizontal distance

We have;

The gradient  = Rate of change of elevation/(Horizontal distance)

Therefore;

The gradient of Ashley's flight = (1000 - 0)/(2.8 - 0) = 357.143 m/km

The gradient of Ashley's flight ≈ 357.143 m/km which is lesser than the required 360 m/km in order to take off and not crash, therefore, she will crash.

What two things must you know to describe the motion of an object? __________________________________________________________________________

Distance is _________________________________________________________________

What is the displacement of a cyclist, who travels 1 mile north, then 1 mile east, and finally 1 mile south? ___________________________

Define speed ________________________________________________________________

How do speed and velocity differ? ______________________________________________
__________________________________________________________________________

How do velocities combine? In opposite directions? ________________________________ In the same direction? ________________________________________________________

A river flows at a velocity of 3 km/h relative to the riverbank. A boat moves upstream at a velocity of 15 km/h relative to the river. What is the velocity of the boat relative to the riverbank? ___________________________________

The rate at which velocity changes is called ________________________

True or false? Acceleration is the result of increases or decreases in speed.

A horse on a carousel that is moving at a constant speed is accelerating because _________________________________________________________________________

True or false? When the final velocity is less than the initial velocity of an object, the acceleration is negative.

The total distance traveled divided by the total time is _______________________

What are some common units for speed (give at least two) _____________ ___________

Define velocity ____________________________________________________________

Define acceleration _________________________________________________________

A quantity that has both magnitude and direction is called a _________________.

WILL MARK BRAINLIEST PLEASE HELP DUE IN 2 MINS
On a distance-time graph speed is a ____________ line and thus a ____________ graph.

On a distance-time graph acceleration is a ___________ line and thus a _______________ graph.

Answers

Answer:

velocity is vector Quantity

Light travels in a transparent material at 2.5 x 10 m/s. Find the index of refraction of the
material.

Answers

I would say 5.6 to the 4 and I’ll I did was add it to both side

We have that for the Question "Light travels in a transparent material at 2.5 x 10 m/s. Find the index of refraction of the material." it can be said that

From the question we are told

Light travels in a transparent material at 2.5 x 10 m/s. Find the index of refraction of the  material.

Generally the equation for the  index of refraction  is mathematically given as

[tex]n=\frac{C}{v}\\\\Therefore\\\\n=\frac{3*10^8}{2.5 * 10 }\\\\n=12000000\\\\[/tex]

Therefore

The  index of refraction  of the material is

n=12000000

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If Newton's third law was true, then why does a table move when I push it? If the table exerted the same amount of force to me, why does it move?​

Answers

The reason is the table has less mass than you. The forces are equal and opposite but masses are not. The acceleration of the table is greater because its mass is smaller.

PLZ HELP ME

1. A stone is thrown horizontally from a cliff 30m high with an initial speed of 20m/s. How far from the cliff does the stone strike the ground?


2. A ball rolls off the edge of a table 1.44m above the floor and strikes the floor at a point 2m horizontally from the edge of the table.

A) What is the time the ball was in the air?


B) What is the initial velocity of the ball?



3. A golfer hits a ball and gives it an initial velocity of 40 m/s, at an angle of 30º above the horizontal.

A) How long does the ball stay in the air?


B) How far horizontally (the range) does the ball travel before hitting the ground?

Answers

Answer:

1. The stone will strike the ground 49.46 m from the base of the cliff

2. A) Approximately 0.542 seconds

B)  Approximately 3.69 m/s

3. A) The time the ball spends in the air is approximately 4.0775 s

B) The horizontal range is approximately  141.25 m.

Explanation:

1. The time it takes the stone to land is given by the equation, t = √(h/(1/2 × g)

∴ t = √(30/(1/2 × 9.81)) ≈ 2.473 seconds

The horizontal distance covered by the stone in that time = 20 × 2.473 ≈ 49.46 m

The stone will strike the ground 49.46 m from the base of the cliff

2. A) The time the ball spends in the air = t = √(h/(1/2 × g)

∴ t = √(1.44/(1/2 × 9.81)) ≈ 0.542 seconds

B) The initial horizontal velocity, u = Horizontal distance/(Time) = 2/0.542 ≈ 3.69 m/s

The initial horizontal velocity ≈ 3.69 m/s

3. A) The time the ball spends in the air is given by the following equation;

t = 2 × u × sin(θ)/g = 2 × 40 × sin(30)/9.81 ≈ 4.0775 s

t ≈ 4.0775 s

B) The horizontal range, R, of the  ball is given by the equation for the range of a projectile as follows;

[tex]Range, R = \dfrac{u^2 \times sin (2 \cdot \theta) }{g}[/tex]

Substituting the known values, gives;

[tex]Range, R = \dfrac{40^2 \times sin (2 \times 30^{\circ}) }{9.81} \approx 141.25 \ m[/tex]

The horizontal range ≈ 141.25 m.

400 N of load can be overcome by an effort of 50 N by using a lever. Calculate the mechanical advantage of the lever.

Answers

Answer:

load (l)=400N

Effort(E)=50N

mechanical advantage (MA)= load ÷Effort

(ma)=400÷50

(ma)=8

Explanation:

I copy pasted from the answer from the same question. Remember to first check if ur question is there

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