A car accelerates from rest to a certain velocity in a certain time. Assume that there is no friction, and that the engine power is constant. Consider the following scenarios independently. How long would it take to reach double the velocity (also from rest)

Answers

Answer 1

Answer:

it will take half of the initial time to reach double the velocity

Explanation:

Given that a car accelerates from rest to a certain velocity in a certain time.

Since the car accelerate from rest, the initial velocity U = 0

Using the first equation of motion,

V = U + at

V = at

Assume that there is no friction, and that the engine power is constant. Consider the following scenarios independently. How long would it take to reach double the velocity (also from rest)

That is V = 2V

Using the same formula ,

2( at ) = at

2T = t

T = t/2

Therefore, it will take half of the initial time to reach double the velocity


Related Questions

A power cycle operating between hot and cold reservoirs at 500 K and 300 K, respectively, receives 1000 kJ by heat transfer from the hot reservoir. The magnitude of the energy discharged by heat transfer to the cold reservoir must satisfy

Answers

Answer:

The value is [tex]Q_l \ge 600\ k J[/tex]

Explanation:

From the question we are told that  

   The temperature of  hot is  [tex]T_h = 500 \ K[/tex]

   The temperature of cold is  [tex]T_c = 300 \ K[/tex]

   The energy received is  [tex]E = 1000 \ kJ = 1000 *10^{3 } \ J[/tex]

Generally the maximum thermal  efficiency of the engine is mathematically represented as

     [tex]\eta = \frac{T_h - T_c}{T_h}[/tex]

=> [tex]\eta = \frac{500 - 300}{500}[/tex]

=> [tex]\eta = 0.4[/tex]

Generally the thermal  efficiency of the engine is  

   [tex]\eta_t = \frac{Q - Q_l}{Q}[/tex]

Here  [tex]Q_l[/tex] is the heat energy rejected

Generally the thermal efficiency must be less than or equal to the maximum thermal  efficiency

So

       [tex]\frac{Q - Q_l}{Q} \le 0.4[/tex]

=>    [tex]\frac{1000 *10^{3} - Q_l}{1000 *10^{3} } \le 0.4[/tex]

the change in inequality sign is because [tex]1000*10^{3}[/tex]  which was dividing started multiplying

=>    [tex]Q_l \ge 1000*10^{3} - 400*10^{-3}[/tex]

=>  [tex]Q_l \ge 600*10^{3} \ J[/tex]

=>  [tex]Q_l \ge 600\ k J[/tex]

A speed skater moving across frictionless ice at 8.8 m/s hits a 6.0 m -wide patch of rough ice. She slows steadily, then continues on at 5.8 m/s . What is her acceleration on the rough ice?

Answers

Recall that

v² - u² = 2 ax

where u and v are initial and final velocities, respectively; a is acceleration; and ∆x is the distance traveled (because the skater moves in only one direction).

So we have

(5.8 m/s)² - (8.8 m/s)² = 2 a (6.0 m)

a = ((5.8 m/s)² - (8.8 m/s)²) / (12 m)

a = -3.65 m/s²

With what force will a car hit a tree if the car has a mass of 3,415 kg and it is accelerating at
a rate of 5 m/s2?

Answers

Answer:

[tex]F= 17,075\ N[/tex]

Explanation:

When the car is under an accelerating force and hits a tree, the instant force received by the tree is the same force that is accelerating the car.

The accelerating force can be calculated using Newton's second law:

[tex]F=m\cdot a[/tex]

Where m is the mass of the car and a is the acceleration.

[tex]F=3,415\ kg\cdot 5\ m/s^2[/tex]

[tex]\boxed{F= 17,075\ N}[/tex]

Write the vectors labeled A, B and C with rectangular coordinates.

Answers

Focus on vector A. Start at the base of the vector which is at (1,1)

Then notice how we have to move 3 units to the right and 2 units up to get to the tip of the vector where the arrow is located. So this is at (4,3)

The fact that we moved 3 units to the right and 2 units up means that vector A is <3, 2>

So we'll type 3 in the first box and 2 in the second box.

======================================================

We use the same idea for vector B

Start at the base and move to the tip. Doing so has us move 1 unit left and 3 units down.

Vector B = <-1, -3>

We type -1 in the first box, and -3 in the second box.

======================================================

Finally onto vector C

Start at the base (0,0). To move to the tip, we need to go 3 units left and 3 units up

Vector C = <-3, 3>

-3 goes in the first box and 3 goes in the second box

======================================================

In general, vectors are useful to tell us a specific direction in which to go. They're useful in physics to determine how exactly a force is being applied, or how a particle is moving.

Hellllllpppppp what happens

Answers

Answer:

u can write ur answer and submit it

its a test

4. A 65 kg woman is inside an elevator. Calculate her apparent weight (Normal Force) for the following cases:

a. The elevator moves at constant speed of 10 m/s downward (2 pts)
b. The elevator accelerates upward at a constant rate of 2.4 m/s2 (2 pts)
c. If the scale read 450 N. Find the magnitude and direction of the elevator’s acceleration. (3 pts)

Answers

Answer:

Explanation:

a ) Let her apparent weight be W₁

Net force on her = W₁ - mg

acceleration a = 0

W₁ - mg  = 0

W₁   =   mg = 65 x 9.8 = 637 N  

b )

a = 2.4 m /s²

W₁ - mg  = ma

W₁  = m(g + a )

= 65 x ( 9.8 + 2.4 )

= 793 N

c )

W₁ = 450 N

a = ?

W₁ - mg  = ma

450 - 65 x 9.8 = 65 x a

65 a = - 187

a = - 2.87 m /s²

acceleration is negative therefore , it must be downwards   .

The elevator was accelerating downward at a constant rate of -3.1 m/s²

Let the acceleration due to gravity (g) = 10 m/s²

a) When moving at constant speed of 10 m/s downward:

Net force = mass * g = 65 kg * 10 m/s² = 650N

b) Net force = Mass * g + mass * acceleration

Net force = (65 * 10) + (65 * 2.4) = 806 N

c) Net force = Mass * g + mass * acceleration

450 = 65 * 10 + (65*a)

65a = -200

a = -3.1 m/s²

The elevator was accelerating downward at a constant rate of -3.1 m/s²

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I am so close to wanting to drop out of physics


I'm in college and idk why physics has to be this tough. I took physics back in high school, and it was super easy & I had a really nice teacher.


But now that I'm in college, my professor does no help and literally 60 people dropped out of his class bc his class is hard. I am going to fail my midterm this week. idk what to do and Im sick and tired but its a requirement.

I literally wanna drop out of college bc of physics

Answers

Answer: Dont drop out i know school can be a headache but if you try you can accomplished anything.

Explanation:

Answer:

college vs high school.

Explanation:

hello! first, i see the comparison between college and highschool. remember that college professors are much more strict. they dont give participation awards or guide you. this is the time to push yourself! your so close to your goal, why give up from one class? you got this! every question you get wrong or right is a step closer to understanding it better. dont give up. i hope i could help!

Calculate the magnetic field at the center of a circular current loop of radius R divided by the magnetic field at a distance R away from a very long straight wire carrying the same current value I. (Note the loop and wire are not in electrical contact.)

Answers

Answer:

The magnetic field at the center of a circular current loop of radius R divided by the magnetic field at a distance R away from a very long straight wire carrying the same current value I is [tex]\pi[/tex] or 3.14

Explanation:

The magnetic field at center of a circular loop is given by

[tex]B = \frac{\mu _{o}I }{2R}[/tex]

Where B is the magnetic field

[tex]\mu _{o}[/tex] is the free space permeability constant ( [tex]\mu _{o}[/tex] = 4π × 10⁻⁷ N/A²)

[tex]I[/tex] is the current

and [tex]R[/tex] is the radius

For the magnetic field of a long straight wire, it is given by

[tex]B = \frac{\mu _{o}I }{2\pi R}[/tex]

Where B is the magnetic field

[tex]\mu _{o}[/tex] is the free space permeability constant ( [tex]\mu _{o}[/tex] = 4π × 10⁻⁷ N/A²)

[tex]I[/tex] is the current

and [tex]R[/tex] is the distance from the wire

Then, to calculate the magnetic field at the center of a circular current loop of radius R divided by the magnetic field at a distance R away from a very long straight wire carrying the same current value I, that will be

[tex]\frac{\mu _{o}I }{2R} \div \frac{\mu _{o}I }{2\pi R}[/tex]

= [tex]\frac{\mu _{o}I }{2R} \times \frac{2\pi R }{\mu _{o}I}[/tex]

= [tex]\pi[/tex]

(NOTE: [tex]\pi[/tex] = 3.14)

Hence, the magnetic field at the center of a circular current loop of radius R divided by the magnetic field at a distance R away from a very long straight wire carrying the same current value I is [tex]\pi[/tex] or 3.14.

Please answer correctly will give brainlist if correct
Before you kick a soccer ball you pull your leg back. For a brief moment, before you kick the ball, your leg is not moving as seen in the image below. At this point, your leg has______
Active Energy
Potential Energy
Conservation of Energy
Kinetic Energy

Answers

If your keg is not moving the only energy your leg can have is Potential energy.

Answer:

Kinetic energy

Which landform represents a piece of land that is formed when a river splits before flowing into the ocean?

Delta
Glacier
Lake
Mountain

Answers

I think the answer is a delta but I could be wrong

Answer:

delta

Explanation:i just got it right

Suppose a rocket-propelled motorcycle is fi red from rest horizontally across a canyon 1.00 km wide. (a) What minimum constant acceleration in the x-direction must be provided by the engines so the cycle crosses safely if the opposite side is 0.750 km lower than the starting point? (b) At what speed does the motorcycle land if it maintains this constant horizontal component of acceleration? Neglect air drag, but remember that gravity is still acting in the negative y-direction.

Answers

motion equation
x
=
a
t
2
2
x=
2
at
2



y
=

g
t
2
2
y=−
2
gt
2



Initial conditions
g
=
9.8
m
s
2
g=9.8
s
2

m


the cycle crosses safely if the...
1000
=
a
t
2
2
1000=
2
at
2




750
=

g
t
2
2
−750=−
2
gt
2



From this we have acceleration
a
=
1000

9.8
750
=
13.1
m
s
2
a=
750
1000⋅9.8

=13.1
s
2

m

Explain how the ESPN network has helped the sports industry grow in the past thirty years. In your explanation, you must also explain whether the industry has peaked or whether potential for growth still exists.

Answers

Answer:

Thirty years ago, the culture of American sports took a new course. An idea shouldered by a former sports communication executive, along with his son and other partners, would go on to transform the way we consume, analyze and interpret the world of athletics, and would influence international sport culture as well. While sports have always acted as a medium for those looking to escape the drudgeries of work, a way to channel negative emotions into something engaging and entertaining, ESPN presented a new opportunity for fans: an all-encompassing cable network for not only sports itself but also for the culture surrounding sports.,

Explanation:

Hope this helped!

A 2070 kg space station orbits Earth at an altitude of 5.37×105 m. Find the magnitude of the force with which the space station attracts Earth. The ma

Answers

Answer:

9.9 × 10^-16N

Explanation:

Given that a 2070 kg space station orbits Earth at an altitude of 5.37×105 m. Find the magnitude of the force with which the space station attracts Earth. 

Calculating the gravitational field strength.

g = Gm/R^2

Where G = 6.67408 × 10-11 m3 kg-1 s-2

g =(6.67408 × 10-11 × 2070)/5.37 × 10^5

g = 1.38069×10^-7 / 2.88369^11

g = 4.788×10^-19 m/s

Force F = mg

Substitute g into the formula

F = 2070 × 4.79×10^-19

F = 9.9 × 10^-16N

What is a factor in an experiment that can be changed or it can be kept the same?

Answers

Answer:  If you are performing an experiment on the effect of spraying plants with different chemicals, you would try to maintain the same pressure and maybe the same volume when spraying your plants. The independent variable is the one factor that you are changing. It is one factor because usually in an experiment you try to change one thing at a time.

Explanation:

Which example illustrates Newton's first law?

Answers

Answer: The motion of a ball falling down through the atmosphere, or a model rocket being launched up into the atmosphere are both examples of Newton's first law. The motion of a kite when the wind changes can also be described by the first law.

Explanation:

how is the process of finding the mass of a gas different from that of finding the mass of a liquid why is the difference necessary​

Answers

Because gas and liquid are both different things

If a wave is traveling at a constant speed, and the frequency increases, what would happen to the wavelength?
It would increase
It would decrease.
It would remain constant.
It would drop to zero.

Answers

If a wave is traveling at a constant speed, and the frequency increases, the wavelength would decrease.

What is wavelength?

The wavelength is the distance between the adjacent crest or trough of the sinusoidal wave. The wavelength is the reciprocal of the frequency of the wave.

Wavelength λ = 1 / frequency

The wavelength and frequency are inversely related to each other. So, when frequency is increased, the wavelength increases.

Thus, the wavelength of would decrease if the frequency increases.

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Answer:

B. It would decrease

Explanation:


Which of the following is an example of homeostasis?

Answers

Answer:

Humans' internal body temperature is a great example of homeostasis. ...

Glucose is the most basic form of sugar, and the only type the body can use directly. ...

When bacteria or viruses that can make you ill get into your body, your lymphatic system kicks in to help maintain homeostasis.

Explanation:

Which Statement describes Newton's law of universal gravitation?

Mass has little effect on gravity between objects

gravity pushes objects away from Earth's center

gravity does not act between Earth and Moon

every object in the universe attracts every other objects

>You will get 100 points for answering this!

Answers

Answer:

The answer is D, every object in the universe attracts every other objects

Explanation:

Newton's law of universal gravitation is described as every object in the universe attracts every other objects.

What is gravitation?

Gravitation is the force in physics that draws two masses together. Unbelievably, every single particle of matter in the cosmos attracts every other particle through gravity. The phrases gravitation and gravity are sometimes used synonymously to refer to the attraction that exists between everything with mass or energy.

According to Newton's Law of Universal Gravitation, every particle in the cosmos is drawn to every other particle with a force that is directly proportional to the product of their masses and inversely proportional to their distance from one another.

So, every object in the universe attracts every other objects describes  Newton's law of universal gravitation.

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answer
prove that p = d g h

Answers

Answer:

Proving LHS=RHS

Explanation:

Given

p=dgh

Multiplying by 0 on both sides of the equations

p×0=dgh×0

0=0

:- Hence proved

Two wires A and B made of the same material and having the same lengths are connected across the same voltage source. If the power supplied to wire A is six times the power supplied to wire B, what is the ratio of their diameters

Answers

Answer:

sqrt (3) : sqrt (2)

Explanation:

Given that Two wires A and B made of the same material and having the same lengths are connected across the same voltage source.

Since they are both made of the same material, they will have the same resistivity.

Resistance is directly proportional to the length of the wire and inversely proportional to the cross sectional area.

Resistance R =1/ πr^2

If the power supplied to wire A is six times the power supplied to wire B, that is,

Pa = 6Pb

Where

Power P = IV

Since the same voltage passes through both wires,

P = V^2/R

Substitutes resistance R into the equation .Therefore,

V^2 ÷ 1 / πr^2 = 6( V^2 ÷ 1 / πr^2 )

V will cancel out , leaving

πr^2 = 6πr^2

Pi( π) will also cancel out. And since diameter d = 2r

r = d/2

Substitutes r into the equation

(d/2)^2 = 6( d/2)^2

d^2/4 = 6( d^2/4)

d^2/4 = 3d^2/2

da^2/2 = 3db^2

(Da/Db)^2 = 3/2

Da : Db = sqrt (3) : sqrt (2)

therefore, the ratio of their diameters is

sqrt (3) : sqrt (2)

The ratio of the diameter of Wire A to Wire B is; √6 : 1

What is the power in the wire?

Since both wires are made of the same material, they will definitely have the same resistivity.

Formula for the resistance with area is;

R = 1/A = 1/(πr²)

We are told that the power supplied to wire A is six times the power supplied to wire B. Thus;,

Pa = 6Pb

Since the same voltage passes through both wires, then formula for power in both cases is; P = V²/R. Thus;

V² ÷ (1/πr_a²) = 6(V² ÷ (1/πr_b²))

V and π will cancel out to give;

r_a² = 6r_b²

We know that radius; r = d/2

Thus;

(d_a/2)²= 6(d_b/2)²

d_a²/4 = 6(d_b²/4)

(d_a/d_b)² = 6

d_a/d_b = √6 : 1

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The cheetah, the fastest land animal, can sprint at 30 m/s. Could the cheetah get a speeding
ticket on a highway where the speed limit is 55 mph?

Answers

Answer:

#1, cheetas can't go 30 miles per second. #2 no

Explanation:

No because animals can't get tickets.

Answer:

yes

Explanation:

it would be going 67.108 mph,

Question 11 of 15
When hydrogen is attached to the more highly electronegative oxygen atom in
a water molecule,
A. the electronegative atom becomes strongly positive
B. the hydrogen atom becomes partially positive
O C. the oxygen atom becomes partially negative

If answer is right WILL GIVE BRAINLIEST
D. the hydrogen atom becomes partially negative

Answers

Answer:

I'm leaning twards A

Explanation:

I think B but I’m not sure

Question 3 of 10
A 0.057 kg tennis ball and a tennis racket collide. The racket has an initial
momentum of -1.75 kg-m/s and a final momentum of -1.25 kg-m/s. The ball
has an initial momentum of 0.00684 kg-m/s. If you assume the collision is
elastic, what is the final velocity of the ball?
A. -0.50 m/s
B. -52.48 m/s
C. -2.99 m/s
d
D. -8.65 m/s

Answers

The answer is d I hope this helps

If we assume the collision to be elastic the final velocity of the ball will be  -8.65 m/s, therefore the correct option is D.

What is elastic collision?

It is a type of Collison for which the momentum, as well as the kinetic energy after and before the collision, is constant. there is no loss of energy in a perfectly elastic collision.

By using the law of conservation of momentum

momentum before collision = momentum after the collision

the initial momentum of rocket +initial momentum, of ball = final momentum of rocket + final momentum of the ball

By substituting the respective values

-1.75 + 0.00684 = -1.25 + m*v

-1.75 + 0.00684 = -1.25 + 0.057*v

v = -8.65 m/s

Thus, the final velocity of the ball is -8.65 m/s

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Your car is initially at rest when your hit that gas and the car begins to accelerate at a rate of 2.857 m/s/s. The acceleration lasts for 15.5 s. What is the final speed of the car and how much ground does it cover during this acceleration?

Answers

Answer:

Vf = 44.56 [m/s]

Explanation:

In order to solve this problem we must use the following expression of kinematics.

[tex]v_{f} = v_{i}+(a*t)[/tex]

where:

Vf = final velocity [m/s]

Vi = initial velocity = 0

a = acceleration = 2.857 [m/s^2]

t = time = 15.5 [s]

Note: the initial velocity is equal to zero as the car begins its movement from rest, or with an initial velocity equal to zero.

Vf = 0 + (2.875*15.5)

Vf = 44.56 [m/s]

What is the momentum of a 76–kilogram horse running at a speed of
45 kilometers/hour?

A.
2.5 × 102 kilogram·meters/second
B.
3.4 × 104 kilogram·meters/second
C.
3.4 × 103 kilogram·meters/second
D.
9.5 × 102 kilogram·meters/second

Answers

Answer:

Option D, is closest to the answer = 950.

Answer: D. 9.5x102 kilogram.meters/second

Explanation:

correct for plato

A stone is thrown vertically upward with the velocity of 25 m/s. How long day
it take to reach the maximum height? Also calculate the height​

Answers

Answer:

The stone takes 2.55 sec to reach a maximum height of 31.89 m

Explanation:

Vertical Motion

When an object is thrown vertically up with a speed vo, it loses speed because of the effect of the gravity and gains height until the speed is eventually zero. The height attained at that time is called maximum height, and can be calculated as follows:

[tex]\displaystyle h_m=\frac{v_o^2}{2g}[/tex]

Since vo=25 m/s

[tex]\displaystyle h_m=\frac{25^2}{2\cdot 9.8}=31.89\ m[/tex]

Also, the time taken to reach the maximum height is calculated by:

[tex]\displaystyle t_m=\frac{v_o}{g}[/tex]

[tex]\displaystyle t_m=\frac{25}{9.8}=2.55\ s[/tex]

The stone takes 2.55 sec to reach a maximum height of 31.89 m

What statements accurately describe sunspots? Check all that apply.
Sunspots are storms on the Sun's surface.
Sunspots are marked by intense magnetic activity.
Sunspots produce solar flares and hot gassy ejections.
Sunspots can affect Earth's climate.
Sunspots are cool areas where the Sun is covered by clouds.

Answers

Answer:

sunspots are storms on the Suns surface

Sunspots are marked by intense magnetic activity

Sunspots produce solar flares and hot gassy ejections.

Sunspots can affect Earth’s climate.

Explanation:

I just did this lesson

The statement that describe sunspot is Sunspots are storms on the Sun's surface.

What are sunspot?

Sunspot are region of the earth that are more darker than other surfaces. They have temporary spots that are darker because the temperature of that area is cooler than other surfaces. They have a reduced temperature.

Therefore, The statement that describe sunspot is Sunspots are storms on the Sun's surface.

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Which statement describes S waves? A. They move side to side.B.They arrive betore P waves. C. They travel through liquids D. They occur at Earth's surtace.​

Answers

Answer: they move side to side

Explanation:

i took the test

Will ice melt faster in salt, sugar or water?

Answers

Answer:

Water because the salt will just make it colder and the sugar won't do anything

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