Please Help Me!!!!!!!​

Answer:

The correct option is;

Why car engines are not perfectly efficient

Explanation:

The Second Law of Thermodynamics states that the total entropy, S, of a system combined with the entropy of its surrounding cannot be decreased, such that for an irreversible process, the entropy always increases and [tex]S_f[/tex] > [tex]S_i[/tex], while for a reversible process the entropy is constant and [tex]S_f = S_i[/tex]

The entropy is a measure of the amount of useful work obtainable from heat (or thermal) energy

A system with a low entropy has high amounts of heat energy capable of doing work while a high entropy system can produce only a small amount of useful work from the available thermal energy

In car engines, as the parts start to move, the entropy of the system increases alongside the generated heat lost to the environment, the amount of heat available for doing work reduces and therefore, the entropy increases further and the ratio of work obtainable from a given input of heat energy reduces and therefore, the car engine is not perfectly efficient.

Answer:

Shape of the object

Explanation:

This depends on the shape of the object. For a spherical object, a unitless value of 0.47 is typical. The magnitude of the velocity squared. The faster you go, the greater the air resistance force

Answer:

A

Explanation:

marijuana affects the brain

In this case, they may be under-performing at school. Hence, option (A) is correct.

Routines that are routinely carried out are referred to as habits. They can also be characterized as behaviors brought on by an internal or external stimulus (Robbins & Costa, 2017). Additionally, habits are the actions you take in specific situations.

Perhaps someone else always brushes their teeth before going to bed. Basically, anything that is repeated frequently enough to become automatic might be considered a habit. You don't really need to consider doing it any more. It simply occurs.

Some would argue that our behaviors are what causes life (or at the very least, success). The routine actions we take shape who we are and the outcomes we attain. Because of this, developing healthy habits and breaking negative ones is a vital life skill that has numerous advantages.

Learn more about habits here:

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Answer:

1

Explanation:

How many digits are in front of the decimal in scientific notation?

Answer:

1. no

2. it would be different because of gravity.

3. no

4. they would be different because of the unit of measurment used. Mexico and any other country would use the metric system.

Answer:

30×6=n

Explanation:

30 students in her class× 6 = number of students in the entire 4th grade.

The force does the racket exert on the ball will be 18 N. Force is defined as the product of mass and acceleration. Its unit is Newton.

Force is defined as the push or pull applied to the body. Sometimes it is used to change the shape, size, and direction of the body.

The given data in the problem is;

The mass of tennis ball is, [tex]\rm m= 0.060 \ kg[/tex]

The speed of tennis ball is,[tex]\rm u = 25m/s[/tex]

The rebound's speed is,[tex]\rm v = 40 \ m/sec[/tex]

The time period of ball is in contact,[tex]\rm t=50 \ ms =50 \times 10^{-3} \ sec[/tex]

The force on the rocket is found as;

[tex]\rm F= m [\frac{v-u}{t}] \\\\\ \rm F= 0.060[ \frac{40-25}{50 \times 10^{-3}} ]\\\\\ F= 18 \ N[/tex]

Hence, the force does the racket exert on the ball will be 18 N.

To learn more about the force, refer to the link;

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Answer:

I don't think so

Explanation:

Answer:

yes

Explanation:

Answer: b. infrared

Explanation:

The visible light with the smaller frequency is associated with the color red.

While the blue is the one with the larger frequency.

Now, as the name says, infrared waves are the ones with a frequency just below the one of the red visible light.

Where the frequency of the red light is something around (4.3*10^14 Hz)

and the frequency of the infrared waves is in the range between (10^12 Hz and 10^14 Hz)

Then the correct option is b, infrared.

Answer:

Acceleration = 1.33m/s² East

Explanation:

Given the following data;

Initial velocity = 10m/s

Final velocity = 50m/s

Time = 30secs

To find the acceleration;

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.

Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.

Mathematically, acceleration is given by the equation;

[tex]Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}[/tex]

[tex]a = \frac{v - u}{t}[/tex]

Where,

a is acceleration measured in [tex]ms^{-2}[/tex]

v and u is final and initial velocity respectively, measured in [tex]ms^{-1}[/tex]

t is time measured in seconds.

Substituting into the equation, we have;

[tex]a = \frac{50 - 10}{30}[/tex]

[tex]a = \frac{40}{30}[/tex]

Acceleration = 1.33m/s² East

Answer:

According to our principle, when an object is slowing down, the acceleration is in the opposite direction as the velocity. Thus, this object has a negative acceleration. In Example D, the object is moving in the negative direction (i.e., has a negative velocity) and is speeding up.

Answer:

[tex]22.4\:\mathrm{kg\cdot m/s}[/tex]

Explanation:

Momentum is given by [tex]p=mv[/tex].

Let [tex]p_1[/tex] be the initial momentum of the object:

[tex]p_1=m\cdot v=22.4[/tex]

If we doubled the mass, the new mass would be [tex]2\cdot m[/tex], and if we halved the velocity, the new velocity would be [tex]\frac{1}{2}\cdot v[/tex].

Therefore, the final momentum would be:

[tex]p_f=2\cdot m\cdot \frac{1}{2}\cdot v=m\cdot v=\fbox{$22.4\:\mathrm{kg\cdot m/s}$}[/tex]..

Answer:

22.4

Explanation:

Acellus

Explanation:

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Calculus 1 : How to find acceleration

Study concepts, example questions & explanations for Calculus 1

Example Questions

Calculus 1 Help » Spatial Calculus » Acceleration » How to find acceleration

Find Acceleration : Example Question #1

The position vector of an object moving in a plane is given by r(t)=3t4i + 6t2j. Find its acceleration when t=1.

Possible Answers:

3i + 2j

36i + 12j

3i + 6j

6i + 2j

36i - 12j

Correct answer: 36i + 12j

Explanation:

To find acceleration at time t, we have to differentiate the position vector twice.

Differentiating the first time gives the velocity:

v(t) = r'(t) = 12t3i + 12tj

Differentiating a second time gives the accelaration:

a(t) = r''(t) = 36t2i + 12j

Plug in t=1 to solve for the final answer:

a(1) = r''(1) = 36i + 12j

Strategies currently being implemented include:

Vapor recovery nozzles at the gasoline pumps to reduce refueling emissions;

Cleaner burning gasoline reformulated to reduce VOC, NOx and other pollutants;

Strict NOx emission limits for power plants and industrial combustion sources;

Enhanced vehicle inspection programs in states; and

Strict limitations on the solvent usage in factories.

hope this helps

Answer:

visible rock fragments

Explanation:

sedimentary rocks start as sediments carried in rivers and deposited in lakes and oceans then get buried so the sediments lose water and become cemented to form the rock.

Answer:

c

Explanation:

Answer:

40kg

Explanation:

that the answer

Answer:

True

its giving an object that has potential energy, kinetic energy.

Explanation:

Answer:

Concept: Periodic Trends

Answer:

D

Explanation:

plz help me with my most recent post if u can

Answer: this answer is definitely c for k12

Explanation:

Answer:

21.25 m/s

Explanation:

The speed of the pitch is equal to the distance the baseball travels (85 m) divided by the time it took for it to cover that distance (4). In short, we are dividing 85 by 4 to reach our answer of 21.25 meters per second.

Answer: It is correct to say iron is heavier than the wood.

Explanation:

It's because the density of iron is more than wood. What is this mean is iron the space between iron molecules in iron much less than as that of wood. So in iron there is more molecules than wood in same volume. More molecules means more mass, that's why iron is much heavier than wood for same volume.

Given that,

Initial velocity of the airplane = 66 m/s

Distance = 560 m

Final velocity of the airplane = 0 (stops)

To find,

Acceleration of the airplane.

Solution,

Let us consider that a is the acceleration of the airplane. We can find it using third equation of motion as follows :

[tex]v^2-u^2=2as\\\\a=\dfrac{v^2-u^2}{2s}\\\\a=\dfrac{0^2-66^2}{2(560)}\\\\a=-3.9\ m/s^2[/tex]

Therefore, the acceleration of the airplane is [tex]-3.9\ m/s^2[/tex]

Answer:

D.) Object 1 has 4x the kinetic energy of object 2

Explanation:

Kinetic Energy

Is the type of energy an object has due to its state of motion. It is proportional to the square of the speed.

The formula for the kinetic energy is:

[tex]\displaystyle K=\frac{1}{2}mv^2[/tex]

Where:

m = mass of the object

v = speed at which the object moves

Now suppose we have two objects with the same mass m1=m2=m and object 1 moves twice as fast as object 2, that is:

[tex]v_1=2v_2[/tex]

Let's compute their kinetic energies:

[tex]\displaystyle K_1=\frac{1}{2}mv_1^2[/tex]

[tex]\displaystyle K_2=\frac{1}{2}mv_2^2[/tex]

Since v1=2v2, the first kinetic energy is:

[tex]\displaystyle K_1=\frac{1}{2}m(2v_2)^2[/tex]

[tex]\displaystyle K_1=4\frac{1}{2}m(v_2)^2[/tex]

Dividing both equations:

[tex]\displaystyle \frac{K_1}{K_2}=\frac{4\frac{1}{2}m(v_2)^2 }{\frac{1}{2}m(v_2)^2}[/tex]

Simplifying:

[tex]\displaystyle \frac{K_1}{K_2}=4[/tex]

Or, equivalently:

[tex]K_1=4K_2[/tex]

Answer:

D.) Object 1 has 4x the kinetic energy of object 2