A 45 kg swimmer starting from rest can develop a maximum speed of 12 m/s over a distance of 20 m How much net force must be applied to do this ?

MUST SHOW WORK!

Answers

Answer 1

F = ma = mΔv/t = m(vf - vi)/t = mvf/t (since vi = 0)

⇒ a = vf/t


While accelerating from rest to vf, the distance d the swimmer traveled satisfies

d = (1/2)at2

Then

d = (1/2)(vf/t)t2 = vf t/2 ⇒

t = 2d/vf

F = ma = mvf/t = mvf / (2d/vf) = mvf2 / (2d)

F = [45 * 122 / (2 * 20)] N = 162 N

If you also want to know how long the swimmer took to accelerate to vf,

t = 2d/vf = (2 * 20 / 12) s = 3.33 s
Answer 2
55m got it right on edg

Related Questions

Alex wants to learn how to surf, but he is not a strong swimmer. He knows he needs to increase his ability to paddle out in order to catch the best waves. Which piece of advice would you give to help him get started on reaching his goal? He should swim at least three times a week at the community pool to build stamina. He should tread water every day to get more comfortable in the water. He should purchase the best surfboard he can afford because it will help him paddle faster. He should watch your friend who is a competitive surfer practice to learn her technique.

Answers

Answer:

He should swim at least three times a week at the community pool to build stamina.

Explanation:

True or false Adding salt to a pot of water will decrease the temperature that water boils at.

Answers

Answer:water gets hot at 212 so incress

Explanation:

Answer:

False

Explanation:

It will increase

WILL MARK BRAINLY!! QUICK HELP PLEASE!
A 40.0 kg rocket produces a
764 N upwards force ("thrust").
What is the net force acting on
the rocket?

Answers

Answer:                                                                              

372                              

Explanation:(40.0)×(9.8)=392

764N-392=372

Explain why the total positive charge in every atom of an element is always the
same.

Answers

Answer:

When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.

Explanation:

An atom has an equal quantity of positive and negative electric charges (the protons and electrons) when its electron and proton counts are equal (the protons). Since the atom has a total electric charge of zero, it is referred regarded as being neutral.

What is an atom?

The atom is the smallest unit of matter that may be divided without resulting in electrically charged particles. Additionally, it is the tiniest substance with features like chemical elements. The atom is therefore the basic building block of chemistry.

Examine different electron arrangements in the electron shells that surround an atom's nucleus.

Examine different electron arrangements in the electron shells that surround an atom's nucleus. The rest is made up of a cloud of negatively charged electrons surrounding a positively charged nucleus made up of protons and neutrons. Compared to electrons, which are the lightest charged particles in nature, the nucleus is small and dense.

To get more information about atom :

https://brainly.com/question/13654549

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26. For this table of data, which column is the independent variable?
radius of circle (m) area of circle (m2)
3.4
36.317
4.5
63.617
4.6
66.476
6.2
120.763
7.6
181.458
7.7
186.265
8.6
232.352
9.7
295.592
area of circle
o
radius of circle
O
None of these is correct.

Answers

Answer:

radius of a circle is measured by an instrument, so it is the independent variable

Explanation:

The independent variable corresponds to the magnitude controlled by the experimenter and in general can be measured by an instrument.

The dependent variable is the variable used to perform the calculations, obtained from a mathematical transformation of the independent variable.

The radius of a circle is measured by an instrument, so it is the independent variable and the area is calculated by

         A = π r²

Therefore the area corresponds to the dependent variable

Describe the last three years of your life. Include positive and negative experiences.
For a middle school girl

Answers

Answer:

my middle school life was horrible and still is sadly ); could you please do my recent brainless <333

Explanation:

My middle school life was eh.i allways got assumed that i was a elementry kid when i was and 6 and 7 grade.until 8th when i hit my grow spurt.my voice end up getting really deep in 8th grade too.tho in 8th i got sent to a certain  type of scholl for kids who did bad because of some dum teacher who lied that i hit her when i actually just went to her desk to get my phone sence she saw it in my pocket and took it away.i got sent there for 3 months and was worst thing ever.the treated us like prisoners in that school and made us tacky uniforms that i refused to where.i believe it was a school for 7th-12th.after my expierence at that school my expierence in 8th grade was almost done.i end up being popular at school for being that kid who hit the teacher.ofc that was like 2 years ago im 10th now.i dont really remember my 6th and 7th grade year.only thing i rember is i was a trouble maker and still am a trouble maker.

hope that helped you:)

please make my answer brainiest as im trying get 4 brainiest answers

I need help in Physics pls help me!

20 points for CORRECT ANSWER!!!

Answers

Answer:

V = 3.65 m/s

Explanation:

The answer is 4.157 m/s

n Olympic diver is on a diving platform 3.60 m above the water. To start her dive, she runs off of the platform with a speed of 1.3 m/s in the horizontal direction. What is the diver's speed, in m/s, just before she enters the water

Answers

Answer:

8.5m/s

Explanation:

Using the equation of motion

v² = u² + 2gH

v is the final speed of the diver

u  is the initial speed of the diver

g is the acceleration due to gravity

H is the height of the object

Given the following

V = 1.3m/s

H = 3.60m

g = 9.8m/s²

Required

Initial speed of the diver u

Substitute the given values into the formula:

v² = u² -2gH

1.3² = u²  - 2(9.8)(3.60)

1.69 = u²-70.56

u² = 1.69+70.56

u² = 72.25

u = √72.25

u = 8.5m/s

Hence the diver's speed, in m/s, just before she enters the water is 8.5m/s

pls help me w this, I've been doing this since 5 minutes ago​

Answers

Answer:

t=0.0625s

Explanation:

F=number of swings/time taken

DATA

Frequency=4.0Hz

number of swings from Q to R

=1/4

time taken=?

Frequency=number of swings/time taken

make t the subject of the formula

t=n/f

substitute the given date

t=0.25/4.0

t=0.0625s

option A is collect

A sound wave passes from air into water and then into steel. With each change in medium, the velocity of this wave will a(increase,then decrease b(decrease c(increase d( decrease,then increase ?

Answers

Answer:

a

Explanation:

because it can increase anything

Why is it colder in winter than summer? Give two reasons.

Answers

Answer:

Actually, the sun goes a bit down, like it's not all the way up as to summer. How I know is that you actually can go online maybe search for some videos and see proof, I don't really know how to explain it.

Explanation:

Reason #1: If you check, go out for 12 hours and see, I think the sun is a little down.

Reason #2:

The earth’s axis is tilted.

From a Brainly user of this question for more info:

The Earth is NOT farther away from the sun in USA Winter, and NOT closer to the sun in USA Summer. In 2021, we will be NEAREST to the sun on January 2, and FARTHEST from the sun on July 5 !

NEAREST to the sun next Saturday.

FARTHEST from the sun next July 5.

Explain why different types of musical instruments sound different, even though they play the same notes.

Answers

each musical instrument is build differently which allows it to portray a different sound kinda like humans with their voices

At which point is the object not moving?

A
B
C
D
All of these.
None of these.

Answers

it’s none of those because it’s moving at a constant rate

Solve for x. 60(cos 50) = x

Answers

Answer:

x=38.56725658

Explanation:

Answer:

x=38.56725658

Explanation:

A merry go round exerts a force of 1000 N on a rider on the
outer ring of animals when it takes 15 seconds to make a
complete revolution. If the person weighs 750 N, the radius
of the circle he is making is m. Round your answer to
the nearest tenth.

Answers

Answer:

The radius of the circle made by the person on the merry go round is 74.55 meters

Explanation:

The given parameters are;

The force the merry go round exerts on the rider = 1000 N

The time it takes the merry go round to make one complete revolution = 15 seconds

The weight of the person = 750 N

The radius of the circle made by the person on the merry go round = r

We have;

[tex]F_c = \dfrac{m \cdot v^2}{r} = m \cdot \omega ^2 \cdot r[/tex]

Where;

m = The mass of the person

v = The velocity of the person

[tex]F_c[/tex] = The centrifugal force acting on the person = 1,000 N

r = The radius of the circle made by the person on the merry go round

ω = Angular velocity = 2·π/15 rad/s

We have;

The mass of the person = The weight/(The acceleration due to gravity, g)

∴ The mass of the person = 750/9.81 ≈ 76.45 kg

By substituting the calculated and known values into the equation for  the centripetal force, we have;

[tex]F_c[/tex] = m × ω² × r

1000 = 76.45 × (2·π/15)² × r

r = 1000/(76.45 × (2·π/15)²) = 74.55 m

The radius of the circle made by the person on the merry go round = r = 74.55 m.

1. The geologic time scale divides time into years and centuries, true or false

Answers

Answer:

The answer is "False"

Explanation:

The geologic time scale is the "schedule" for occasions in Earth history. It partitions time into named units of unique time called in descending order of duration "eons, eras, periods, epochs, and ages". The specification of those geologic time units depends on stratigraphy, which is the relationship and order of rock layers. The fossil structures that happen in the stones, nonetheless, give the central methods for setting up a geologic time scale, with the circumstance of the development and vanishing of far and wide species from the fossil record being used to outline the beginnings and endings of ages,, periods, and different stretches.

Geologic time is the broad time period involved by the geologic history of Earth. Formal geologic time starts toward the beginning of the Archean Eon (4.0 billion to 2.5 billion years back) and proceeds to the current day.

Draw a picture showing the possible phases of the moon in this binary star
system, do they look the same or different from those we see in the sky in
reality? (You might want to think about scale and how far the suns would be
when considering your answer.)

(Help ASAP)

Answers

Is this what your talking about if not sorry

A 10 kg object experiences an acceleration of 2 m/s squared. What net force was applied to the object?

Answers

F = ma

= 10kg × 2m/s

= 20N

Answer : 20N

Explanation :

F = Force (N)

m = mass (kg)

a = acceleration (m/s)

A car with a mass of 900 kg is traveling at a
speed of 25 m/s. What is the kinetic energy
from the car's motion?

Answers

Explanation:

Kinetic Energy

= 0.5mv²

= 0.5(900kg)(25m/s)²

= 281,250J.

A loudspeaker produces a sound wave of frequency 50hz.
The amplitude of sound wave is increased.
What is heard?
A) a louder sound of higher pitch.
B) a louder sound of the same pitch.
C) a sound of higher pitch but the same loudness.
D) a sound of the same pitch and loudness as before.

Answers

Hey mate
Here is your answer
Option A)
Explanation:
The larger the amplitude of the waves, the louder the sound. Pitch (frequency) – shown by the spacing of the waves displayed. The closer together the waves are, the higher the pitch of the sound.
Pls mark as brainliest

Four measurements of the file card's width are made. Of the measurements given below, the LEAST precise.
O 7.62
O 7.63
O 7.34
O 7.6

Answers

7.6 is the least precise

Epithelial tissues often form the lining of organs and secrete substances such as digestive enzymes.

True
False

Answers

Answer:

ohh yes. answer is true

False it’s false false false

The temperature of rock located 1,000 kilometers below the Earth's surface is about a. 200 C b.2,100 C c.2,800 C d.3,200 C

Answers

The temperature would be 3,200 °C!!

Brainliest, please! <3

The temperature of the rock located at 1,000 km below the earth' surface has been 3200 degree Celsius. Thus, option D is correct.

The temperature at the earth's surface has been found to be nearly 0 degree Celsius. According to the geology of the earth, the temperature has been increased to 1500 degree Celsius by digging 100 km below the earth surface.

Thus, the temperature at 100 km from earth surface has been 1500 degree Celsius.

On moving down from 100 km, there has been a rise in temperature, and at the mouth of the mantle at 1000 km, the temperature has been approximately 3500 degree Celsius.

Thus the temperature that has been near  about 3500 degree Celsius is 3200 degree Celsius. Thus, the temperature of the rock at 1000 km below the earth surface has been 3200 degree Celsius. Thus, option D is correct.

For more information about the temperature of earth, refer to the link:

https://brainly.com/question/893891

a beaker weighs 0.4N when empty and1.4N when filled with water what does ot weigh when filled with brine of density 1.2 g/cm3

Answers

Answer: 1.6 N

Explanation:

The weight of an object is calculated as:

W = g*m

where:

g = gravitational acceleration = 9.8m/s^2

m = mass of the object.

We also know that:

mass = density*volume.

or:

m = d*v

Let's start:

The weight of the beaker is 0.4N

And the weight of the beaker filled with water is 1.4N

Then the weight of the water alone will be:

1.4N - 0.4N = 1N = (d*v)*9.8m/s^2

And we know that the density of the water is:

1 g/cm^3

But we are working with Newtons, then we need to rewrite this with kilograms as the mass unit, we can use that:

1000g = 1kg

Now we can rewrite the density as:

d = 1 g/cm^3 = 1*(1/1000) kg/cm^3 = 0.001 kg/cm^3

Replacing that in the above equation, we get:

With this, we can find the volume that the water occupies.

W = 1 N = v* 0.001 kg/cm^3*9.8m/s^2

       1 N /( 0.001 kg/cm^3*9.8m/s^2 ) = 102.04 cm^3.

Now, when we fill it with a brine with a density of 1.2 g/cm^3, the mass of this brine in a volume of  102.04 cm^3 be:

M = (1.2 g/cm^3)*( 102.04 cm^3) = 122.448 g

Rewriting this in kg we get:

M = 122.448 g = (122.448/1000) kg = 0.122448 kg

Then the weight of this brine is:

M = 0.122448 kg*9.8m/s^2 = 1.2 N

And the beaker weighs 0.4N, then the beaker filled with this brine will weight:

1.2 N + 0.4N = 1.6 N

question in the photo

Answers

I think (50 joules ) I’m not sure

Using Velocity vs Time Graphs to Find Acceleration
A graph titled velocity versus time has horizontal axis time (seconds) and vertical axis velocity (meters per second). A line has 4 straight segments. Line segment A runs from 0 seconds 0 meters per second to 1 seconds 15 meters per second. Then segment B runs to 2 seconds 20 meters per second. Then segment C runs to 4 seconds 20 meters per second. Then segment D runs to 5 seconds 0 meters per second.

The acceleration of segment D is m/s2.



Rank segments A, B, and C from least acceleration to greatest acceleration.

Least:








Greatest:

Answers

The acceleration at segment D is -20m/s²

The rank of the acceleration from the least to the greatest is -20m/s² < 0m/s² < 5m/s² < 10m/s² (D<C<B<A)

Acceleration is the change in velocity with respect to time.

a = v-u/t

Acceleration at segment A:

Aa = 15-0/1-0

Aa = 15m/s²

Acceleration at segment B:

Ab = 20-15/2-1

Ab = 5m/s²

Acceleration at segment C:

Aa = 0-0/4-2

Aa = 0m/s²

Acceleration at segment D:

Ac = 0-20/5-4

Ac = -20m/s²

Hence the acceleration at segment D is -20m/s²

The rank of the acceleration from the least to the greatest is -20m/s² < 0m/s² < 5m/s² < 10m/s² (D<C<B<A)

Learn more here: https://brainly.com/question/18398656

Which frequency would be the third harmonic in a series for an open-pipe resonator if the fundamental is 440 Hz

Answers

Answer:

1320 Hz

Explanation:

The third harmonic is given as 3fo, where fo is the fundamental frequency.

The fundamental frequency is the lowest frequency that can occur in a pipe. In an open pipe, both even and odd harmonics occur which are multiples of the fundamental frequency fo. Hence the harmonics in an open pipe are; 2fo, 3fo,4fo..... etc.

For the third harmonic; 3fo = 3 (440 Hz) = 1320 Hz

A teacher pushes a cart, while a student pushes a second, heavier cart
with the same amount of force. If the student's cart has three times the
mass as the teacher's, which of the following is true? *

Answers

Answer:

frictional force acting on the cart 450 N.

Given:

mass of cart = 50 kg

acceleration = 3

To find:

Frictional force = ?

Formula used:

F -  = 600 N

F = ma

= frictional force

Solution:

Force on the block is given by,

F -  = 600 N

F = ma

= frictional force

= 600 - m a

= 600 - (50 × 3)

= 600- 150

= 450 N

According to the given data the frictional force acting on the cart 450 N.

A ball of mass 0.12kg is hit by a tennis player. The velocity of the ball changes from 0m/ s to 5.0m/s in 0.60s. What is the average resultant force acting on the ball while it is being hit?
A 1.0N B 2.5N C 3.6N D 8.3N
(Please add explanation)

Answers

Answer:

A. 1.0N

Explanation:

According to Newton's second law

F = ma

m is the mass = 0.12kg

a is the acceleration = v-u/t

a = 5-0/0.6

a = 5/0.6

a = 8.333m/s²

Get the force

F = 0.12 * 8.333

F = 1.0N

Hence the average resultant force acting on the ball while it is being hit is 1.0N

The fall of a body on the earth surface cannot be a complete free fall ? why

Answers

It can never be in a total free fall due to air resistance and terminal velocity due to mass
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