You are playing with a yoyo . If Potential energy of the yoyo is 18 J , and the total mechanical energy is 20 J , how much kinetic energy does the yoyo have ?​

Answer:

My biggest reason is to make it a habit. Even if the ball goes into the endzone it is a live ball and the offensive players must down the ball. Don't leave any room for "I thought he downed it" or "I thought I heard the whistle" just run to the ball always.

If the players slow down and the returner takes it out of the end zone it could be a big return. Players are on a full sprint for 40+ yards sometimes and instead of breaking down, they choose to contine through the goal line to slow down at a decreased rate (possibly limiting a muscle pull injury).

Answer:

b

Explanation:

A researcher who does not want to manipulate or interfere with the behavior of research subjects would conduct a  Naturalistic observation study.

    Observational technique in the research field is usually, " watching something attentively in a scientific manner". If we are observing research technique and its phenomena naturally it's our interest to see in our own subjects. The subject will be known only when we observe the things. It's all about understanding, analyzing, predicting and manufacturing in a unique manner.

The types of observation techniques are:

Naturalistic observation:

 This is the observation which can be observed naturally and the phenomenon will be interacted only with the researchers not with the participants.

Some of the observational research methods are:

Hence, Option B is the correct answer.

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Answer:

- 21⁰C .

Explanation:

Speed of jet = 2.05 x 10³ km /h

= 2050 x 1000 / (60 x 60 ) m /s

= 569.44 m / s

Mach no represents times of speed of sound , the speed of jet

1.79 x speed of sound = 569.44

speed of sound = 318.12 m /s

speed of sound at 20⁰C = 343 m /s

Difference = 343 - 318.12 = 24.88⁰C

We know that 1 ⁰C change in temperature changes speed of sound

by .61 m /s

So a change in speed of 24.88 will be produced by a change in temperature of

24.88 / .61

= 41⁰C  

temperature = 20 - 41 = - 21⁰C .  

When a ball of mass m makes a head-on elastic collision with a second ball (at rest) and rebounds in the opposite direction with a speed equal to one-fourth its original speed, then mass of the second ball having v/3 is velocity after collision is 9m/4.

Momentum is defined as mass times velocity of body. it is denoted by p and its SI unit is Kg.m/s. It has both magnitude and direction. it is a vector quantity.  it tells about the moment of the body. it is denoted by p and expressed in kg.m/s. mathematically it is written as p = mv. A body having zero velocity or zero mass has zero momentum. its dimensions is [M¹ L¹ T⁻¹]. Momentum is conserved throughout the motion.

initial momentum = final momentum

Given,

mass of first body m₁ = m

initial velocity of first body = v₁' = v

final velocity of first body = v₁'' =v/4

mass of second body m₂ = ?

initial velocity of second body = v₂' = 0

final velocity of second body = v₂'' = v/3

According to conservation of momentum,

initial momentum = final momentum

m₁v₁' + m₂v₂' = m₁v₁'' + m₂v₂''

putting al above values

m₁v + 0 = m₁v/4 + m₂v/3

m₁v - m₁v/4 = m₂v/3

m (1 - 1/4)v = m₂v/3

3m/4 = m₂/3

m₂ = 9m/4

Hence mass of the second body is 9m/4.

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A computer is a programmable device that can automatically perform a sequence of calculations or other operations on data once programmed for the task. It can store, retrieve, and process data according to internal instructions. A computer may be either digital, analog, or hybrid, although most in operation today are digital. Digital computers express variables as numbers, usually in the binary system. They are used for general purposes, whereas analog computers are built for specific tasks, typically scientific or technical. The term "computer" is usually synonymous with a digital computers, and computers for business are exclusively digital.

Answer:

The core, computing part of a computer is its central processing unit (CPU), or processor. ... A computer system, therefore, is a computer combined with peripheral equipment and software so that it can perform desired functions.

Explanation:

Hope the answer was helpful

Answer:

0.3106 seconds

Explanation:

Frequency= 20,000-Hz

The speed of echoes sounds can be calculated using the expression below;

Y= ( 2x/t) ...........................eqn(1)

t= overall time taken

x = maximum depth = 230m

Y= speed of echoes sounds

Speed of sound in water= 1,481 m/s which is a constant with little variation.

If we substitute the given values into eqn(1) we have

1481 = (2× 230)/ t

1481 × t= 460

t=460/1481

t=0.3106 seconds

Hence, the minimum time between pulses (in fresh water) is 0.3106 seconds

Answer: C. A few alpha particles bounced off a thin sheet of gold foil.

Answer:

63.8 kJ

Explanation:

The net work output per cycle is the difference in heat input and heat output. The heat input and heat output are expressed as a function of volume ratios, while volume is expressed as a function of pressure and pressure as a function of temperature.

R = 287 J/kg.K, k = 1.4

Hence the net work input (W) is given as:

[tex]W=Q_{in}-Q_{out}\\\\W=mR[T_Hln\frac{V_2}{V_1} -T_Lln\frac{V_3}{V_4}]\\\\=mR[T_Hln\frac{P_1}{P_2} -T_Lln\frac{P_4}{P_3}]\\\\=mR[T_Hln(\frac{P_1}{P_3}(\frac{T_L}{T_H} )^\frac{k}{k-1}) -T_Lln(\frac{P_1}{P_3}(\frac{T_L}{T_H} )^\frac{k}{k-1})]\\\\=mR(T_H-T_L)ln(\frac{P_1}{P_3}(\frac{T_L}{T_H} )^\frac{k}{k-1})\\\\Substituting\ values:\\\\W=mR(T_H-T_L)ln(\frac{P_1}{P_3}(\frac{T_L}{T_H} )^\frac{k}{k-1})=0.6*287(1100-300)ln(\frac{3000*10^3}{2-*10^3}(\frac{300}{1100} )^\frac{1.4}{1.4-1})\\\\[/tex]

[tex]W=63.8\ kJ[/tex]

Answer:

Einstein's equivalence principle says that __________.

the effects of gravity are exactly equivalent to the effects of acceleration

Explanation:

The equivalence principle is one of the fundamental laws of physics, as enunciated by Einstein.  It categorically states that the gravitational and inertial forces are of a similar nature.  In physics, a gravitational acceleration is the acceleration of an object in a free fall within a space.  The importance of Einstein's Equivalence Principle is explained by his theory of general relativity.  This theory states that mass is the same, whether inertial or gravitational.

According to the Einstein's equivalence principle, the effects of gravity are exactly equivalent to the effects of acceleration.

Einstein's equivalence principle says that  the effects of gravity are exactly equivalent to the effects of acceleration.

Einstein's equivalence principle states that the the force due to gravity and the force of inertia are similar in the nature and there is no need to distinct them.

Thus Einstein's equivalence principle says that  the effects of gravity are exactly equivalent to the effects of acceleration.

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Answer:

Option B. O because the net force was 5 N in Alfredo's direction

Explanation:

To know the the correct answer to the question given above, we shall determine the net force acting on the bat. This can be obtained as follow:

Force of pull by Mason (Fₘ) = 15 N

Force of pull by Alfredo (Fₐ) = 20 N

Net force (Fₙ) =?

Fₙ = 20 – 15

Fₙ = 5 N in Alfredo's direction

From the calculation made above, we can see that the net force is 5N in Alfredo's direction. This is the reason why Alfredo end up having the bat.

Answer:

Here its right but its also better than Barney's response

Explanation:

W, Y, Z, X or C

Answer:

W, Y, Z, X

Explanation:

Answer:

1 m/s

Explanation:

5m/s change in velocity, divided by 5 seconds= 1 meter/second/second

change in velocity/change in time

Acceleration = (change in velocity) / (time for the change)

that's = (change in speed and its direction) / (time for the change)

Change in velocity = (ending velocity) - (starting velocity)

Change in velocity = (20 m/s west) - (15 m/s west)

Change in velocity = 5 m/s west

Acceleration = (5 m/s west) / (5 seconds)

Acceleration = 1 m/s west

Answer:

The answer is below

Explanation:

We are going to use Gauss’ law to find the electric field equation. Since electric field is coming from an infinite line of charge, hence it is going out in a radial direction.  

Therefore we use the area of the electric field which passes through, forming a Gaussian cylinder. We neglect the ends of the area.

Hence:

[tex]\int\limits {E} \, dA=\frac{Q_{enc}}{\epsilon_o}\\\\E(2\pi rL)= \frac{\lambda L}{\epsilon_o}\\\\E=\frac{\lambda}{2\pi r\epsilon_o} \\\\Given \ that:\\\\r=a=8.7\ cm=0.087\ m, \lambda=-2.3 \mu C/cm=-2.3*10^{-4}\ C/m,\epsilon_o=8.85*10^{-12}F/m.\\\\Hence:\\\\E=\frac{-2.3*10^{-4}}{2\pi *0.087*8.85*10^{-12}}=-4.75*10^7\ N/C[/tex]

The value of the x-component of the electric field is -475213.968 newtons per coulomb.

In this question we shall apply Gauss' Law to determine the magnitude of the electric field ([tex]E_{x}[/tex]), in newtons per coulomb, rapidly and based on the assumptions of uniform charge distribution and cylindrical symmetry.

[tex]\frac{Q_{enc}}{\epsilon_{o}} = \oint\,\vec E\,\bullet d\vec A[/tex] (1)

Where:

Based on all assumptions, we simplify (1) as follows:

[tex]\frac{\lambda\cdot l}{\epsilon_{o}} = E \cdot (2\pi\cdot r\cdot l)[/tex]

And the equation of the x-component of the electric field is:

[tex]E = \frac{\lambda}{2\pi\cdot \epsilon_{o}\cdot r}[/tex] (2)

Where [tex]\lambda[/tex] is the linear charge density, in coulomb per meter.

If we know that [tex]\lambda = -2.3\times 10^{-6}\,\frac{C}{m}[/tex] and [tex]a = 0.087\,m[/tex], then the electric field produced by the line of charge at point P is:

[tex]E = \frac{\left(-2.3\times 10^{-6}\,\frac{C}{m} \right)}{2\pi\cdot \left(8.854\times 10^{-12}\,\frac{s^{4}\cdot A^{2}}{kg\cdot m^{3}} \right)\cdot (0.087\,m)}[/tex]

[tex]E_{x} = -475213.968 \,\frac{N}{C}[/tex]

The value of the x-component of the electric field is -475213.968 newtons per coulomb. [tex]\blacksquare[/tex]

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Answer:

Potential energy: Greatest at the top of the hill

Kinetic energy: Greatest at the bottom of the hill

The two meet at some point on the way down!

Explanation:

Potential energy is energy that represents an object's potential for motion. Kinetic energy is that object's energy during motion. They're two sides of the same coin, and in fact, their sum gets a special name: mechanical energy. Potential energy builds up in reaction to working against certain forces - in the case of the roller coaster, that primary force is gravity. Gravity exerts a downward force on the roller coaster, and it takes work to pull it up the hill.

When it reaches the peak, the coasters potential energy is at its highest, and the moment it crests over the hill and begins its descent, that gravitational potential energy starts converting into kinetic energy: the coaster starts accelarating down the track, and the potential energy decreases at the same rate that the kinetic energy increases.

At the bottom of the hill, all of that potential energy has become kinetic energy, and the coaster zooms along the track, hopefully not giving too many riders nausea

Answer:

The new force becomes 4 times the initial force.

Explanation:

The force of attraction or repulsion is given by the relation as follows :

[tex]F=k\dfrac{q_1q_2}{d^2}[/tex]

Where

d is the distance between the interacting charges

F is inversely proportional to the distance between charges.

If the distance is halved, d'=(d/2), new force is given by :

[tex]F'=k\dfrac{q_1q_2}{d'^2}\\\\=k\dfrac{q_1q_2}{(\dfrac{d}{2})^2}\\\\=k\dfrac{q_1q_2}{\dfrac{d^2}{4}}\\\\=4\times \dfrac{kq_1q_2}{d^2}\\\\F'=4F[/tex]

So, the new force becomes 4 times the initial force.

Answer:

See explanation below

Explanation:

The question is incomplete. The missing part of this question is the following:

"While the block is in contact with the spring and being brought to rest, what are (a)the work done by the spring force and (b) the increase in thermal energy of the blockfloor system? (c) What is the blocks speed just as it reaches the spring?"

According to this we need to calculate three values: Work, Thermal Energy and Speed of the block when it reaches the spring.

Let's do this by parts.

a) Work done by the spring:

In this case, we need to apply the following expression:

W = -1/2 kx²  (1)

We know that k = 430 N/m, and x is the distance of compressed spring which is 5.8 cm (or 0.058 m). Replacing that into the expression:

W = -1/2 * 430 * (0.058)²

b) Increase in thermal energy

In this case we need to use the following expression:

ΔEt = Fk * x   (2)

And Fk is the force of the kinetic energy which is:

Fk = μk * N   (3)

Where μk is the coeffient of kinetic friction

N is the normal force which is the same as the weight, so:

N = mg (4)

Let's calculate first the Normal force (4), then Fk (3) and finally the chance in the thermal energy (2):

N = 4.8 * 9.8 = 47.04 N

Fk = 0.28 * 47.04 = 13.1712 N

Finally the Thermal energy:

ΔEt = 13.1712 * 0.058

c) Block's speed reaching the spring

As the block is just reaching the speed, the initial Work is 0. And the following expression will help us to get the speed:

V = √2Ki/m   (5)

And Ki, which is the initial kinetic energy can be calculated with:

Ki = ΔU + ΔEt   (6)

And ΔU is the same value of work calculated in part (a) but instead of being negative, it will be positive here. So replacing the data first in (6) and then in (5), we can calculate the speed:

Ki = 0.7233 + 0.7639 = 1.4872 J

Finally the speed:

V = √(2 * 1.4872) / 4.8

Hope this helps

Answer:

How can I help you??? Plz insert some questions

Answer: 109.4 mm

Explanation: Distance is a scalar quantity and it is the measure of how much path there are between two locations. It can be calculated as the product of velocity and time:  d = vt

The separation between the two steamrollers is 105 mm or 0.105 m. They collide to each other at the middle of the separation:

location of collision = [tex]\frac{0.105}{2}[/tex] = 0.0525 m

To reach that point, both steamrollers will have spent

[tex]v=\frac{\Delta x}{t}[/tex]

[tex]t=\frac{\Delta x}{v}[/tex]

[tex]t=\frac{0.0525}{1.2}[/tex]

t = 0.04375 s

The fly is travelling with speed of 2.5 m/s. So, at t = 0.04375 s:

d = 2.5*0.04375

d = 0.109375 m

Until it is crushed, the fly will have traveled 109.4 mm.

Answer:

the initial speed of the arrow before joining the block is 89.85 m/s

Explanation:

Given;

mass of the arrow, m₁ = 49 g = 0.049 kg

mass of block, m₂ = 1.45 kg

height reached by the arrow and the block, h = 0.44 m

The gravitational potential energy of the block and arrow system;

P.E = mgh

P.E = (1.45 + 0.049) x 9.8 x 0.44

P.E = 6.464 J

The final velocity of the system after collision is calculated as;

K.E = ¹/₂mv²

6.464 = ¹/₂(1.45 + 0.049)v²

6.464 = 0.7495v²

v² = 6.464 / 0.7495

v² = 8.6244

v = √8.6244

v = 2.937 m/s

Apply principle of conservation of linear momentum to determine the initial speed of the arrow;

[tex]P_{initial} = P_{final}\\\\mv_{arrow} + mv_{block} = (m_1 + m_2)V\\\\0.049(v) + 1.45(0) = (0.049 + 1.45)2.937\\\\0.049v = 4.4026\\\\v = \frac{4.4026}{0.049} \\\\v = 89.85 \ m/s[/tex]

Therefore, the initial speed of the arrow before joining the block is 89.85 m/s

The arrow moving as the speed of "76.36 m/s".

According to the question,

By using the conservation of energy, we have

→                [tex]K.E=P.E[/tex]

→ [tex]\frac{1}{2} (m_1+m_2)v_2^2= (m_1+m_2)gh[/tex]

or,

→                    [tex]v_2 = \sqrt{2mgh}[/tex]

By substituting the values, we have

→                         [tex]= \sqrt{2\times 9.8\times 0.44}[/tex]

→                         [tex]=2.469 \ m/s[/tex]

Now,

By using the conservation of momentum, we get

→ [tex]m_1 v_1 = (m_1+m_2) v_2[/tex]

or,

→      [tex]v_1 = \frac{(m_1+m_2)v_2}{m_1}[/tex]

            [tex]= \frac{1.45+0.049}{0.049}\times 2.469[/tex]

            [tex]= 30.6\times 2.496[/tex]

            [tex]= 76.36 \ m/s[/tex]

Thus the above approach is correct.  

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Answer and Explanation: No, the explanation is not plausible. The puck sliding on the ice is an example of the Principle of Conservation of Energy, which can be enunciated as "total energy of a system is constant. It can be changed or transferred but the total is always the same".

When a player hit the pluck, it starts to move, gaining kinetic energy (K). As it goes up a ramp, kinetic energy decreases and potential energy (P) increases until it reaches its maximum. When potential energy is maximum, kinetic energy is zero and vice-versa.

So, at the beginning of the movement the puck only has kinetic energy. At the end, it gains potential energy until its maximum.

The representation is as followed:

[tex]K_{i}+P_{i}=K_{f}+P_{f}[/tex]

[tex]K_{i}+0=0+P_{f}[/tex]

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

As we noticed, mass of the object can be cancelled from the equation, making height be:

[tex]h=\frac{v^{2}}{2g}[/tex]

So, the height the puck reaches depends on velocity and acceleration due to gravity, not mass of the puck.

All the objects are motionless, so kinetic energy of each object is zero after the collision.

The kinetic energy of an object is defined as the energy which is  possesses due to its motion. It is the work required to accelerate a body of a given mass from rest to its stated velocity. This energy is gained during its acceleration, the body maintains the kinetic energy as long as its momentum does not change.

Kinetic Energy can be expressed as

[tex]K.E.=[/tex] [tex]1/2 mv^2[/tex]

Where, m is the mass of the object

v is the velocity.

It is expressed in joules (J).

After the collision all the objects are at rest, therefore, the final kinetic energy is also zero which shows maximum loss of kinetic energy. Such collisions are called perfectly inelastic.

Thus, all the objects are motionless, so kinetic energy of each object is zero after the collision.

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Answer:

A. Retina

Explanation:

Answer:

30J

Explanation:

Given parameters:

Mass of hamster  = 0.104kg

Velocity  = 24m/s

Unknown:

Kinetic energy  = ?

Solution:

Kinetic energy is the energy due to the motion of a body. It is mathematically derived by;

  Kinetic energy  = [tex]\frac{1}{2}[/tex] m v²  

m is the mass

v is the velocity

  Kinetic energy  = [tex]\frac{1}{2}[/tex] x 0.104 x 24²   = 30J

Answer:

D = -4/7 = - 0.57

C = 17/7 = 2.43

Explanation:

We have the following two equations:

[tex]3C + 4D = 5\ --------------- eqn (1)\\2C + 5D = 2\ --------------- eqn (2)[/tex]

First, we isolate C from equation (2):

[tex]2C + 5D = 2\\2C = 2 - 5D\\C = \frac{2 - 5D}{2}\ -------------- eqn(3)[/tex]

using this value of C from equation (3) in equation (1):

[tex]3(\frac{2-5D}{2}) + 4D = 5\\\\\frac{6-15D}{2} + 4D = 5\\\\\frac{6-15D+8D}{2} = 5\\\\6-7D = (5)(2)\\7D = 6-10\\\\D = -\frac{4}{7}[/tex]

D = - 0.57

Put this value in equation (3), we get:

[tex]C = \frac{2-(5)(\frac{-4}{7} )}{2}\\\\C = \frac{\frac{14+20}{7}}{2}\\\\C = \frac{34}{(7)(2)}\\\\C = \frac{17}{7}\\[/tex]

C = 2.43

Answer:

There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces. Static friction is strongest, followed by sliding friction, and then rolling friction, which is weakest. Fluid friction occurs in fluids, which are liquids or gases.

Explanation:

Answer:

Explanation:

C 200÷100=2

Output ÷ Input= MA

Answer and Explanation: To know how much tape he will need, we have to calculate the perimeter of each parallelogram-shaped stripe.

Perimeter is the sum of all the sides of a figure.

For a parallelogram:

P = 2*length + 2*width

So, we need to determine width and length of the stripe.

Width is 3 inches. Length is the hypotenuse of the right triangle, whose sides are 6 and 18 inches. Then, length is

[tex]h=\sqrt{18^{2}+6^{2}}[/tex]

[tex]h=\sqrt{360}[/tex]

h = 19 in

Perimeter of the first stripe is

P = (2*19) + (2*3)

P = 44 inches

The hazard sign has 3 stripes. So total perimeter is

[tex]P_{t}=[/tex] 44 + 44 + 44

[tex]P_{t}=[/tex] 132 inches

To outline the parallelogram-shaped stripes, Charles need a total of 132 inches of tape. Since one roll has 144 inches, he will have enough tape to finish the job.

Assuming the particle is in free fall once it is shot up, its vertical velocity v at time t is

v = 30 m/s - g t

where g = 9.8 m/s² is the magnitude of the acceleration due to gravity, and its height y is given by

y = (30 m/s) t - 1/2 g t ²

(a) At its maximum height, the particle has 0 velocity, which occurs for

0 = 30 m/s - g t

t = (30 m/s) / g ≈ 3.06 s

at which point the particle's maximum height would be

y = (30 m/s) (3.06 s) - 1/2 g (3.06 s)² ≈ 45.9184 m ≈ 46 m

(b) It takes twice the time found in part (a) to return to 0 height, t ≈ 6.1 s.

(c) The particle falls 35 m below its starting point when

-35 m = (30 m/s) t - 1/2 g t ²

Solve for t to get a time of about t ≈ 7.1 s