In which of the cases below is friction most helpful?

A.

between a moving box and a ramp

B.

between car tires and a road

C.

between a person and a playground slide

D.

between ice skates and an ice rink

Answers

Answer 1

Answer:

between car tires and a road

Explanation:


Related Questions

A 29000-kg open railroad car, initially coasting at 0.825 m/s with negligible friction, passes under a hopper that dumps 117500 kg of scrap metal into it.

a)What is the final speed, in meters per second, of the loaded freight car?
b)How much kinetic energy is lost, in joules, when the freight car receives this scrap metal? Ignore the free-fall kinetic energy of the scrap metal.

Answers

Answer:

a) Answer: 0.16331 m/s

b) Answer: 8522.66 joules

Explanation:

The final speed is  0.1633 m/s.

When the freight car receives this scrap metal, 7915.72 Joule kinetic energy is lost.

What is momentum?

A body has momentum while it is moving, according to our understanding. It is said that a body's momentum is equal to the sum of its mass and speed. A body's direction is important when discussing momentum. Its direction belongs to the body's direction of motion.

(a) Given parameter:

Mass of the railroad car, M = 2900 Kg.

Mass of the scrap metal, m= 11750 Kg.

Initial speed of the car, u = 0.0825 m/s.

Initial speed of the scrap metal = 0 m/s.

Final speed of the system, v = ?

Then, initial momentum of the  system = initial momentum of the car +  initial momentum of the scrap metal .

= (29000×0.825 + 117500×0) kg.m/s.

= 23925 kg.m/s.

Final momentum of the system = total mass of the system× final speed

= (29000 + 117500)× v kg.m/s

= 146500v kg.m/s.

Hence, from principle of conservation of momentum,

initial momentum of the  system = Final momentum of the system

⇒ 23925 = 146500v

⇒ v = 0.1633 m/s.

The final speed of the  loaded freight car is 0.1633 m/s.

(b) Lost in kinetic energy = initial kinetic energy of the car - final kinetic energy of the loaded car.

= 1/2*29000*0.825² -1/2*(29000 + 117500)* 0.1633² Joule.

= 7915.72 Joule.

Hence, 7915.72 Joule kinetic energy is lost in this process.

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Part B
Based on the information in the article, how could plants be used in the future to help counteract some human
emissions?

Answers

Answer:

Having more plants performing photosynthesis could help reduce the amount of carbon dioxide in the atmosphere.

Explanation:

sample answer

The plants can be used in the future to help counteract some human

emissions they absorb carbon dioxide from the air and release oxygen.

What is photosynthesis?

It is a process carried out by photosynthetic autotrophic organisms, such as plants, algae and some prokaryotes. These organisms capture sunlight, convert it into chemical energy, which will be used to produce organic compounds, based on water and carbon dioxide.

Trees, like other plants, in the process called photosynthesis, absorb carbon dioxide from the air and release oxygen. They also make the air wetter and cooler. In this way, plants contribute to the good quality of the air we breathe.

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A plane flying above the ground has 60,000 joules of kinetic energy and 6,000 joules off gravitational potential energy. How much mechanical energy does the plane have?

Answers

Answer:

66,000J

Explanation:

Mechanical energy = Gravitational energy + Kinetic Energy

ME = 6,000 + 60,000 = 66000 J

What is the velocity of a ball swung around on a rope with a
radius of 0.25 meters and period of 0.40 seconds?

Answers

A ball swung around on a rope of a radius of 0.25 meters in a time of 0.40 seconds, then the velocity of the ball will be equal to 3.925 m/s.

What is velocity?

Velocity is the rate of change of a traveling object's direction, as measured by a certain unit of time and as seen from a specific vantage point. Speed is a basic concept in kinematics, the branch of special relativity that studies how bodies move.

A scientific vector quantity called velocity must have both a magnitude and direction to be described.

As per the data provided in the question,

Radius, r = 0.25

Time, t = 0.40 seconds

Circumference of the circle, d = 2πr

d = 2π(0.25)

d = 1.570 m

Velocity, v = d / t

v = 1.570 / 0.40

v = 3.925 m/s.

Therefore, the velocity of the ball will be 3.925 m/s.

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An 8kg mass is placed on a 30 degrees frictionless inclines plane and is attached to a pulley to a hanging mass of 5kg
Calculate which direction will the system flow
B)what is the acceleration
C)the tension in the rope

Answers

Hi there!

We can begin by doing a summation of forces. Let the acceleration be positive in the direction of the DOWNWARD movement of the hanging block.

(A)

The system will flow in the direction of the hanging block's movement downwards.

(B)

Summation of forces of block on incline:

∑F = -M₁gsinФ + T

Summation of forces of hanging block:

∑F = M₂g - T

Sum both summations:

∑F =  -M₁gsinФ + T + M₂g - T

∑F = M₂g -M₁gsinФ

According to Newton's Second Law:

∑F = ma

Thus:

(M₁ + M₂)a = M₂g -M₁gsinФ

[tex]a = \frac{M_2g -M_1gsin\theta}{M_1 + M_2}[/tex]

Plug in the values:

[tex]a = \frac{(5 * 9.8) -(8 * 9.8 * sin30)}{8 + 5} = \large\boxed{0.754 m/s^2}[/tex]

(C)

Calculate the rope's tension using one of the above equations:

∑F₂ = M₂g - T

Rearrange for T:

T = M₂g - m₂a

Plug in values:

T = 5(9.8) - 5(0.754) = 45.23 N

The initial temperature of the mixture was +20 °C. The mixture froze at -1.5 °C.
A total of 165 kJ of internal energy was transferred from the mixture to cool and
freeze it.
specific heat capacity of the mixture = 3500 J/kg °C
specific latent heat of fusion of the mixture = 255 000 J/kg
Calculate the mass of the mixture.
Give your answer to 2 significant figures.
[6
M

Answers

Answe16000/3500(-1.5-2-)225000= 1.1

Explanation:

The mass of the mixture will be 2.19 ×10⁻³ kg. The unit of mass is kg and it is a scalar quantity.

What is mass?

Mass is a numerical measure of inertia, which is a basic feature of all matter. It is, in effect, a body of matter's resistance to a change in speed or position caused by the application of a force.

In the International System of Units (SI), the kilogram is the unit of mass.

The given data in the problem is;

The initial temperature of the mixture was, [tex]\rm T_i = 20 ^0 \ C[/tex]

The mixture froze at the temperature of, [tex]\rm T_F = -1.5 ^0 \ C[/tex]

The internal energy is,[tex]\rm E = \rm 165 \ kJ[/tex]

The specific heat capacity of the mixture is,[tex]\rm C = 3500 J/kg ^0C[/tex]

The specific latent heat of fusion of the mixture is,[tex]\rm l = 255 000 J/kg[/tex]

m is the mass of the mixture,

The latent heat is equal to the heat transfer. Because the net work done is zero.

The formula for the heat transfer is found as;

[tex]\rm Q = mCdt \\\\ m = \frac{Q}{Cdt} \\\\ m = \frac{165 }{3500(20-(-1.5)} \\\\ m = 2.19 \times 10^{-3} \ kg[/tex]

Hence the mass of the mixture will be 2.19 ×10⁻³ kg.

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How much force is needed to accelerate a 70 kg rider and the 200kg motorcycle the
rider is on at 4m/s?

Answers

Answer:   F = (200 kg + 70 kg) * 4 m/s² = 270 kg* 4m/s² = 1080 N

Answer:

F = 1080 N

Explanation:

Josh and jake are both helping to build a brick wall which is 6 meters in height. They each lay 250 bricks, but josh finishes this task in 3 hours while jake requires 4.5 hours to complete his part. Who does more work, or do they both do the same amounth? Who has more power? Explain.

Answers

Each laid 250 bricks but while Jake was
still working, Josh was lounging in the
shade. Josh has more power but that
power was only on for 3 hours out of 4.5.
Obviously Josh could get more done is less
time as long as he keeps working. Jake will
get the hang of it soon.

change 176°F to the Celsius and Kelvin scales. pura batana kese hua fir answer dena plzz​

Answers

Formulas change from F to degree C : C = (F – 32) / 1.8

so we have (176-32) /1.8= 80 oC

Formulas change from F to degree K : K = 5 / 9 x (F – 32) + 273.15

so we have 5/9 x (176-32) + 273.15 = 353 oK

ok done. Thank to me :>

a helicopter cruises at a constant velocity when the total thrust of the engines is 5,000 N. How much air resistance acts on the jet ??

Answers

Hi there!

[tex]\large\boxed{F_{A} = -5000N}}[/tex]

For an object to be moving at constant velocity:

∑F = 0 (The sum of the forces acting on the object MUST be 0 N)

We can do a summation of forces for this helicopter in the HORIZONTAL direction:

∑Fₓ = Ft (Force of Thrust) + Fa (Force of air resistance) = 0

Thus, if we substitute in the given value for Ft:

Ft = -Fa

5000N = -Fa

Fa = -5000N

PLEASE HELP! I NEED TO ANSWER THIS QUICKLY!
1. What are the uses of microwaves in society today? Give examples
2. What advantages and/or disadvantages have microwaves as a technology had for humans
a) health b) economy and c) human living conditions?

Answers

Answer:

I'm not a genius ok?

Explanation:

1. Radar communication, Analysis of the molecular and atomic structure, telephone communication

2. c

We are able to walk toward because…

a) we push on the air
b) we push on the ground
c) the air pushes on us
d) the ground pushes on us

Answers

The answer is C because of gravity

We are able to walk toward because b) we push on the ground.

_

_

_

[tex] 😘 \: 😉 \: 😈 \; 😫 \: 😤 \: 😡 \: 😘[/tex]

Can you achieve Light Speed with a Perpertual Motion Machine containing High Energy?​

Answers

Answer:

Yes

Explanation:

Perpetual Motion Machine (PMM) which can be applied to produce electricity, may be an alternative solution for the problem the world is facing today. The machine is designed to generate power from repulsive forces of permanent magnet without utilizing external sources.

A wrecking ball has a mass of 650 kg. It swings from a cable that is 21 m long. The centripetal force on the ball is 56 N. What is the tangential speed of the wrecking ball? 1. 3 m/s 1. 8 m/s 46 m/s 870 m/s.

Answers

Hi there!

For an object moving in a circle:

Centripetal force = ∑F = mv²/r

Thus:

56 = mv²/r

Rearrange to solve for velocity:

√(56r/m) = v

√(56 × 21)/650 = 1.345 m/s

Answer:

A

Explanation:

have a good day

A balloon with a volume of 2. 0 L at 25°C is placed in a hot room at 35°C. The pressure on the balloon is constant at 1. 0 atm. How does the volume of the balloon change after moving it to the hot room?.

Answers

Answer:

25A°C=2L

35A°C=? More

=35/25×2L

=7/5×2L

=14L/5

=2.8L

How long does it take a plane, traveling at a constant speed of 200 m/s, to fly once around a circle whose radius is 2750 m

Answers

Answer:

2000 and 156300

jade it jawaban nya

A car takes 9 m to stop after the driver applies the brakes.

The brakes exert a force of 2000 N.

Calculate how much work is done by this force.

Answers

Depends upon how soon you want to stop. You know the mass of the car, you know the initial velocity of 8.9 m/s. You know the final velocity which is zero. You can now calculate the deceleration of the car if you know how soon you want to stop.

Let's say you want to stop in one second.

a = (vf - vi) / t = - 8.9 m/s^2 (negative sign indicates deceleration).

F = ma = 800 x 8.9 = 7120 Newtons (kg*m/s^2)

How would the gravity between two objects change if one object got bigger?

Answers

The correct answer is the 3rd answer, gravity would increase its pull on the small object

hope this helps! :)

HELP PLEASE
2. What is the potential energy of a 2000 g basketball that is stuck on the rim of a 3m hoop?

Answers

Answer:

[tex]U_g=58.86 J[/tex] or [tex]U_g=60 J[/tex]

Explanation:

Answer is attached. I do not know if you needed to use 9.81 or 10 for the acceleration due to gravity, so both solutions are attached.

What is the only force that can overcome the repulsion between two positively charged nuclei to bind them into an atomic nucleus

Answers

Answer:

Nuclear Fusion

Explanation:

At large distances, two nuclei repel one another because of the repulsive electrostatic force between their positively charged protons. If two nuclei can be brought close enough together, however, the electrostatic repulsion can be overcome by the attractive nuclear force, which is stronger at close distances.

helppp
A crane accelerates a 175 kg load is upward. The tension in the cable is 2000 N. Find the magnitude and direction of the elevator's acceleration.​

Answers

Hi there!

We can begin by summing forces acting on the load:

∑F = T - Mg (where g ≈10 m/s²)

ma = T - Mg

We can plug in the given values to solve:

ma = 2000 - 175(10)

175a = 250  

a = 250/175 = 1.43 m/s² UPWARDS

Answer:

a = 1.63 m/s^2

Explanation:

m = 176kg

Ft = 2000N

  2000 = 175 (9.8) +175(a)

    2000   = 1715 +175a

    -1715       -1715

285 = 175a

175     175

a = 1.63m/s^2  

Which element is in the 3rd period and group 16?

Answers

Answer:Thus for n=1 number of electrons is 2 and for n=2 the number of electrons is 8. Hence the electronic configuration of the element X is 2,8,6 and its atomic number is 16. In the Modern Periodic Table, the element Sulphur has atomic number 16. So, the solution is that the element X is Sulphur and it is non metallic.

Answer:

Explanation:

Answer: Thus for n=1 number of electrons is 2 and for n=2 the number of electrons is 8. Hence the electronic configuration of the element X is 2,8,6 and its atomic number is 16. In the Modern Periodic Table, the element Sulphur has atomic number 16. So, the solution is that the element X is Sulphur and it is non metallic.

A ball is released freely from the top of a building 80m high. Find its speed.​

Answers

At the top of the building, the speed of the ball is zero.

The speed increases steadily as the ball falls.

When it hits the street, its speed is 39.6 m/s.

Please help, and give an explanation on what you did. Thanks a lot :]​

Answers

Answer:

3.0 m

Explanation:

The height of the wave is just 1.5 m + 1.5 m which equals 3.0 m

Which country is considered to have one of the best ski teams in the world?

Answers

Answer:

France

Explanation:

France is the undisputed champion in the world of skiing.

If a 5.00 kg box slides down a ramp inclined at 60.0° above the horizontal, what is the

acceleration of the box

Answers

Answer:

A 70 kg box is slid along the floor by a 400 n force. The coefficient of friction between the box and the floor is 0. 50 when the box is sliding

help with this question

Answers

Answer:

D and B.

Explanation:

The wavelength must be taken from the same corresponding point. D and B are both at the crests of a wave, with no other crests in between, which means the distance between them is equal to one wavelength.


Usain Bolt has a mass of 94.1 kg and he had a KE of 7,250 J when running the one hundred meter dash. Calculate how fast he was running

Answers

Answer:

[tex]\displaystyle v = 12.4134 \ m/s[/tex]

General Formulas and Concepts:

Energy

Kinetic Energy Formula: [tex]\displaystyle KE = \frac{1}{2}mv^2[/tex]

m is mass (in kg)v is velocity (in m/s)

Explanation:

Step 1: Define

Identify variables.

KE = 7250 J

m= 94.1 kg

Step 2: Solve for v

Substitute in variables [Kinetic Energy Formula]:                                       [tex]\displaystyle 7250 = \frac{1}{2}(94.1)v^2[/tex]Isolate v term:                                                                                               [tex]\displaystyle 154.091 = v^2[/tex]Isolate v:                                                                                                         [tex]\displaystyle v = 12.4134[/tex]

Topic: AP Physics 1 - Algebra Based

Unit: Energy

A car was driving at a speed of 10 m/s. In 3 seconds, it accelerated to a speed of 50 m/s. Calculate the car's acceleration.

30 m/s2

16.7 m/s2

13.3 m/s2

Answers

Answer:

[tex]\boxed {\boxed {\sf 13.3 \ m/s^2}}[/tex]

Explanation:

Acceleration is the rate of change of velocity with respect to time. It is the change in velocity over the change in time, and it is calculated using the following formula.

[tex]a= \frac{ v_f-v_i}{t}[/tex]

The car starts at a speed of 10 meters per second, then it accelerates to a speed of 50 meters per second. It achieves this acceleration in 3 seconds.

[tex]v_f[/tex]= 50 m/s[tex]v_i[/tex]= 10 m/s t= 3 s

Substitute the values into the formula.

[tex]a= \frac{50 \ m/s - 10 \ m/s}{3 \ s}[/tex]

Solve the numerator.

50 m/s -10 m/s= 40 m/s

[tex]a= \frac{40 \ m/s}{3 \ s}[/tex]

Divide.

[tex]a= 13.3333333 \ m/s/s[/tex]

[tex]a \approx 13.3 \ m/s^2[/tex]

The car's acceleration is approximately 13.3 meters per second squared.

Who is the author "talking” to in the third stanza of Flanders field

Answers

I’m not sure if it’s correct but here u go

In Flanders Fields” is written in the voice of a group of soldiers who have recently died in a World War I battle. By speaking as a group and asking the reader to join in their struggle, these speakers suggest that war is a shared responsibility that affects everyone.

Answer:

One of Canada's best-known poems, “In Flanders Fields” was written on May 2, 1915, when Canadian serviceman John McCrae was stationed at an army hospital in Flanders, Belgium, during World War I.

Explanation:

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