Select all the correct answers.
Which statements are true?
A farsighted person's cornea and lens refract light too much.
A nearsighted person's cornea and lens do not refract light enough.
A person whose eyes are blue has irises that reflect blue light.
Even people with perfectly working eyes have a blind spot in each eye.
A lens with cataracts absorbs or scatters light that it should refract.

Answer:

d) the second law of thermodynamics

Explanation:

Here we take an example

The entropy represents a measurement of the energy dispersal in the system. Also, the campfire would an entropy example. The burning of the solid wood and then it became the ash, smoke and gases this all would be spread the energy to the outward as compared to the solid fuel

Therefore as per the given statement, the correct option is d.

Answer:

when a sled is moving, the kinetic energy is changing beacuse of the speed and mass. its cause the sled to move, and changes because you aren't at a constant speed. potential energy changes when you get on. because you are adding more weight causing the gravity to change.

Answer:

a) ll and Ill only

Explanation:

Let the mass of the wrench = m

and the mass of the astronaut = M

Initially, the velocity of the astronaut and wrench are zero.

The astronaut throws the wrench in one direction and subsequently recoils back with a velocity in the opposite direction.

Let v and V be the velocity of the wrench and the velocity of the astronaut respectively.

In space, there is no external force acting, the momentum must be conserved.

So, m(0)+M(0)=m(v)+M(V)

So, 0=mv+MV

[tex]\Rightarrow mv=-MV[/tex] ...(i)

Here, the momentum of the wrench = mv, and the momentum of the astronaut= MV. The negative sign showing that both the momentum are in opposite direction.

Therefore, the momentum of the wrench is equal and opposite to the momentum of the astronaut.

According to Newton's second law, the rate of change of momentum = applied force.

Let it take [tex]\Delta t[/tex] seconds to change the momentum.

So, for the wrench

[tex]m(v-0)/\Delta t= F_w \\\\\Rightarrow m(v-0)=F_w\Delta t \\\\\Rightarrow mv=F_w\Delta t \cdots(ii)[/tex]

Here, [tex]F_w\Delta t[/tex] is the impulse applied to the wrench.

Similarly, for the astronaut

[tex]M(-V-0)/\Delta t= F_a[/tex] [negative sign (-V) for opposite direction]

[tex]\Rightarrow M(-V-0)=F_a\Delta t \\\\\Rightarrow -MV=F_a\Delta t[/tex]

Here, [tex]F_a\Delta t[/tex] is the impulse applied to the astronaut.

So, the impulse on the astronaut.

By using equations (i) and (ii)

[tex]F_a\Delta t=F_w\Delta t[/tex]

Therefore, the impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut.

Hence, option (a) is correct.

Answer:

False

Explanation:

We still use the old way. It's easier to understand the old way, and its NOT outdated.

Answer:

7,539 m/s

Explanation:

Let's use this equation to find the gravitational acceleration of this space shuttle:

We know that G is the gravitational constant: 6.67 * 10^(-11) Nm²/kg².

M is the mass of the planet, which is Earth in this case: 5.972 * 10^24 kg.

r is the distance from the center of Earth to the space shuttle: radius of Earth (6.3781 * 10^6 m) + distance above the Earth (630 km → 630,000 m).

Plug these values into the equation:

Remove units to make the equation easier to read.

Multiply the numerator out.

Add the terms in the denominator.

Simplify this equation.

The acceleration due to gravity g = 8.11045189 m/s². Now we use the equation for acceleration for an object in circular motion which contains v and r.

a = g, v is the velocity that the space shuttle should be moving (what we are trying to solve for), and r is the radius we had in the previous equation when solving for g.

Plug these values into the equation and solve for v.

Remove units to make the equation easier to read.

Multiply both sides by 7,008,100.

Take the square root of both sides.

The shuttle should be moving at a velocity of about 7,539 m/s when it is released into the circular orbit above Earth.

If the acceleration constant..

you can use the formula s = ut + 1/2at²

Known that :

s = ?

u = 0

t = 2s

a = 10ms-²

Then you can apply the formula

s = ut + 1/2at²

s = 0 + 1/2(10)(2)²

s = 5 × 4

s = 20m

Answer : 20m

Explanation :

The gravity can be 9,8 or 10. Also im not sure how people teach you but in my school, if the ball goes down the gravity is positive and not negative thats why i put 10ms-² and not -10ms-²

s = displacement/distance

u = initial speed

a = acceleration

t = time

sorry if im wrong

Answer:

The Greeks had drama and arts competitions that were considered very popular, and important in society.

Explanation:

hope it helps!

Answer:

velocity = 16.05 m/s

Explanation:

inelastic collision formula:

m1u1 + m2u2 = (m1 + m2)v

m1 = 4kg

u1 = 20m/s

m2 = 15kg

u2 = 15m/s

find v ?

m1u1 + m2u2 = (m1 + m2)v

(4×20) + (15×15) = (4+15)v

80 + 225 = 19v

305 = 19v

19v = 305

v = 305/19

v = 16.05 m/s

Answer:

a)  I = ([tex]\frac{M}{3}[/tex] + [tex]\frac{4m}{9}[/tex]) L²  ,   b)     w = (\frac{27 M}{18 m} + 2)⁻¹  Lv₀

Explanation:

a) The moment of inertia is a scalar that represents the inertia in circular motion, therefore it is an additive quantity.

The moment of inertia of a rod held at one end is

         I₁ = 1/3 M L²

The moment of inertia of the mass at y = L

        I₂ = m y²

The total inertia method

        I = I₁ + I₂

        I = \frac{1}{3} M L² + m (\frac{2}{3} L)²

        I = ([tex]\frac{M}{3}[/tex] +[tex]\frac{4m}{9}[/tex] ) L²

b) The conservation of angular momentum, where the system is formed by the masses and the bar, in such a way that all the forces during the collision are internal.    

Initial instant. Before the crash  

       L₀ = I₂ w₀  

angular and linear velocity are related  

       w₀ = y v₀  

      w₀ = [tex]\frac{2}{3}[/tex]L v₀  

      L₀ = I₂ y v₀  

Final moment. After the crash  

      [tex]L_{f}[/tex] = I w

how angular momentum is conserved  

      L₀ = L_{f}

      I₂ y v₀ = I w

substitute

      m ([tex]\frac{2L}{3}[/tex])² (\frac{2L}{3} v₀ =  ([tex]\frac{M}{3}[/tex] +[tex]\frac{4m}{9}[/tex] ) L²  w

      [tex]\frac{6}{27}[/tex]  m L³ v₀ = ([tex]\frac{M}{3}[/tex] +[tex]\frac{4m}{9}[/tex] ) L²  w

        [tex]\frac{6}{27}[/tex]  m L v₀ = ([tex]\frac{M}{3}[/tex] +[tex]\frac{4m}{9}[/tex] )   w

        L v₀ = [tex](\frac{27 M}{18 m} + 2)[/tex]  w     

       w = (\frac{27 M}{18 m} + 2)⁻¹  Lv₀

Answer:F(of gravity) = MA

F(normal force) = MA * cos(angle)

F = 72 * 9.81 * cos28

Don't have a calculator, so can't really do all the math right there. So just plug that in

Explanation:

i dont really know

Potential energy of a body is the product of its mass, height and acceleration due to gravity. The potential energy of 75 Kg skateboard sitting at 5 meter high is 3675  J.

What is potential energy?

Potential energy of a body is generated by virtue of the position of the body. It is dependent  on the mass of the body and the height at which it is placed and the acceleration due to gravity.

Whereas kinetic energy of an object is a form of energy generated by virtue of the motion of the object. Kinetic energy is dependent on the mass and velocity of the body.

It is given that the mass of the object is 75 Kg and the height from the surface is 5 m. Acceleration due to gravity on earth is 9.8 m/s².Thus, the potential energy is calculated as follows:

p = m g h

 = 75 Kg × 9.8 m/s²  × 5 m

 =  3675   J.

Therefore, the potential energy of the skateboard is  3675  J.

To find more on potential energy, refer here:

http://brainly.com/question/24284560

#SPJ2

Question 4

B. Toby is correct because the rock is experiencing a negative acceleration, causing its positive velocity to decrease until the rock reaches a velocity of O m/s before becoming negative.

Question 5

At the maximum height, velocity is 0, so:

v = v₀ - gt

0 = 14.75 - 9.8t

t = 14.75/9.8

t = 1.5 s    (OPTION A)

4). In the given situation, the assertion that could be made regarding Toby would be:

B). Toby is correct because the rock is experiencing a negative acceleration, causing its positive velocity to decrease until the rock reaches a velocity of O m/s before becoming negative.

5). The time that would be taken by the rock to attain its greatest height would be:

1.5 second

4). Tobby correctly states as rock would be undergoing a -ve acceleration which leads its +ve velocity to fall by the time rock attains the velocity of 0 m/s.

Thus, option B is the correct answer.

5). Given that,

Initial velocity([tex]v_{0}[/tex]) = 14.75 m/s

As we know,

Velocity remains 0 m/s at the greatest height,

So,

Velocity(v) [tex]= v_{0} - gt[/tex]

where

[tex]0 = 14.75 - 9.8t[/tex]

⇒ [tex]t = 14.75/9.8[/tex]

 ∵ [tex]t = 1.5 s[/tex]

Learn more about "Velocity" here:

brainly.com/question/18084516

Explanation:

By Hooke's Law, Fe = kx.

Since Fe = 1.6N and x = 9.2cm - 8cm = 1.2cm,

k = Fe/x = 1.6N/1.2cm = 1.33N/cm.

Answer:

So, given the eqn Fg=G(m1+m2/r^2) where G is the gravitational constant, m is the mass of the satellite and m2 is the mass of the earth and r is the distance from earth to the satellite, the force of earths gravity should be quartered.

Cause (2r)^2 gets turned into (4r^2) where 4r^2 is compared to r^2

Explanation:

Answer:

6.77m/s

Explanation:

Using the law of conservation of momentum

m1u1 + m2u2 = (m1+m2)v

m1 and m2 are the masses of the object

u1 and u2 are the velocities before collision

v is the final collision

Given

m1 = 300g  = 0.3kg

u1 = 6.0m/s

m2 = 10g = 0.01kg

u2 = 30m/s

Required

The bird's speed immediately after swallowing v

Substitute the given values into the formula

m1u1 + m2u2 = (m1+m2)v

0.3(6) + 0.01(30) = (0.3+0.01)v

1.8+0.3 = 0.31v

2.1 = 0.31v

v = 2.1/0.31

v = 6.77m/s

Hence the bird's speed immediately after swallowing is 6.77m/s

Using Newtons Second Law:

F = m×a

F = (0.25 kg)(-2 m/s²)

F = -0.5 N

Answer:an inspirational statement of an idealistic emotional future

Explanation:

I don't know if it's right tho

Answer:

The document that state tge currentand future objectives of an organization.

Answer:

The value is  [tex]|v| = 7.39 \ m/s[/tex]

Explanation:

From the question we are told that

    The angular speed is  [tex]w = 2030 \ rpm = \frac{2030 * 2 * \pi }{ 60} = 212.61 \ rad/s[/tex]

    The distance between the minimum and maximum external position is  [tex]d = 6.95 \ cm = 0.0695 \ m[/tex]

Generally the amplitude of the crank shaft is mathematically represented as

         [tex]A = \frac{d}{2}[/tex]      

=>     [tex]A = \frac{0.0695}{2}[/tex]    

=>     [tex]A = 0.03475 \ m[/tex]

Generally the maximum speed of the piston is mathematically represented as

        [tex]|v| = A * w[/tex]  

=>    [tex]|v| = 0.03475 * 212.61[/tex]

=>    [tex]|v| = 7.39 \ m/s[/tex]

My opinion about friction is that It always acts in the opposite direction as the motion of the object.

Friction refers to the resistance of motion of one object that is moving relative to another object. Fricton has many application but it has also many disadvantages.

So we can conclude that friction is always acts in the opposite direction as the motion of the object.

Learn more about friction here: https://brainly.com/question/24338873

Answer:

a) v = 5.59x10³ m/s

b) T = 4 h

c) F = 1.92x10³ N

Explanation:

a) We can find the satellite's orbital speed by equating the centripetal force and the gravitation force as follows:

[tex] F_{c} = F_{G} [/tex]

[tex]\frac{mv^{2}}{r + h} = \frac{GMm}{(r + h)^{2}}[/tex]

[tex] v = \sqrt{\frac{gr^{2}}{r+h} [/tex]          

Where:

g is the gravity = 9.81 m/s²        

r: is the Earth's radius = 6371 km

h: is the satellite's height = r = 6371 km      

[tex]v = \sqrt{\frac{gr^{2}}{2r}} = \sqrt{\frac{gr}{2}} = \sqrt{\frac{9.81 m/s^{2}*6.371 \cdot 10^{6} m}{2}} = 5.59 \cdot 10^{3} m/s[/tex]                                      

b) The period of its revolution is:

[tex] T = \frac{2\pi}{\omega} = \frac{2\pi (r + h)}{v} = \frac{2\pi (2*6.371 \cdot 10^{6} m)}{5.59 \cdot 10^{3} m/s} = 14322.07 s = 4 h [/tex]

c) The gravitational force acting on it is given by:

[tex] F = \frac{GMm}{(r + h)^{2}} [/tex]

Where:

M is the Earth's mass =  5.97x10²⁴ kg    

m is the satellite's mass = 782 kg

G is the gravitational constant = 6.67x10⁻¹¹ Nm²kg⁻²

[tex] F = \frac{GMm}{(r + h)^{2}} = \frac{6.67 \cdot 10^{-11} Nm^{2}kg^{-2}*5.97 \cdot 10^{24} kg*782 kg}{(2*6.371 \cdot 10^{6} m)^{2}} = 1.92 \cdot 10^{3} N [/tex]

I hope it helps you!

Answer:

It enabled them to run faster from predators.

Explanation:

The evolution of hooves from a five-digit feet enabled horses to run faster from predators as well as support their larger weights and longer legs. Hope this helped and have an awesome day! :)

It enabled them to run faster from predators. ]

Explanation: The evolution of hooves from a five-digit feet enabled horses to run faster from predators as well as support their larger weights and longer legs.

"Radiocarbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon."

Answer:

well for me I think

Explanation:

The use of carbon 12 to tell the age of substances

Answer:

μ = 0.849

Explanation:

In order to solve this problem we must remember that the friction force is defined as the product of the coefficient of friction by the normal force. And normal force is defined as the component of force in the opposite direction to the weight of the body (chair).

As in the y axis there is no movement we can say that the sum of the forces on the chair is equal to zero.

∑Fy = 0

[tex]N-W=0[/tex]

where:

N = normal force [N] (units of Newtons)

W = weight of the chair = m*g [N]

m = mass = 15 [kg]

g = gravity acceleration = 9.81 [m/s²]

[tex]N=m*g\\N=15*9.81\\N=147.15 [N][/tex]

Now the key to solving this problem is to understand that we start applying force on the horizontal component until the chair starts to move at this moment the friction component is calculated with the static friction coefficient. As the chair doesn't move we can say that the sum of force in the horizontal direction is equal to zero.

∑Fx = 0

[tex]F -f_{force} = 0[/tex]

F = force applied = 125 [N]

fforce = friction force = μ*N

μ = friction coefficient (static)

N = normal force = 147.15 [N]

[tex]125-u*147.15=0\\u = 125/147.15\\u = 0.849[/tex]

Answer:

protons are in the nucleus .

Explanation:

there are 6 protons

Answer:

electrical energy

Explanation:

sorry I'm really tired but trust me on this one

Answer:

electrical to thermal and light

Explanation:

The FitnessGram Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. A single lap should be completed each time you hear this sound. Remember to run in a straight line, and run as long as possible.

Answer:

[tex]5.33\ m/s[/tex]

Explanation:

[tex]We\ know\ that,\\Momentum=Mass*Velocity\\p=mv\\Hence,\\Lets\ first\ consider\ the\ case\ of\ the\ two\ balls\ 'Before\ Collision':\\\\Mass\ of\ the\ green\ ball=0.2\ kg\\Initial\ Velocity\ of\ the\ green\ ball=5\ m/s\\Initial\ Momentum\ of\ the\ green\ ball=5*0.2=1\ kg\ m/s\\\\Mass\ of\ the\ pink\ ball=0.3\ kg\\Initial\ Velocity\ of\ the\ pink\ ball=2\ m/s\\Initial\ Momentum\ of\ the\ pink\ ball=0.3*2=0.6\ kg\ m/s\\\\Total\ momentum\ of\ both\ the\ balls\ 'Before\ Collision'=1+0.6=1.6\ kg\ m/s[/tex]

[tex]Hence,\\Lets\ now\ consider\ the\ case\ of\ the\ two\ balls\ 'After\ Collision':\\\\Mass\ of\ the\ green\ ball=0.2\ kg\\Final\ Velocity\ of\ the\ green\ ball=0\ m/s\\Final\ Momentum\ of\ the\ green\ ball=0\ kg\ m/s\\\\Mass\ of\ the\ pink\ ball=0.3\ kg\\Final\ Velocity\ of\ the\ pink\ ball=v\ m/s\\Final\ Momentum\ of\ the\ pink\ ball=0.3*v=0.3v\ kg\ m/s\\\\Total\ momentum\ of\ both\ the\ balls\ 'After\ Collision'=0+0.3v=0.3v\ kg\ m/s[/tex]

[tex]As\ we\ know\ that,\\Through\ the\ law\ of\ conservation\ of\ momentum,\\In\ an\ isolated\ system:\\Total\ Momentum\ Before\ Collision=Total\ Momentum\ After\ Collision\\Hence,\\1.6=0.3v\\v=\frac{1.6}{0.3}=5.33\ m/s[/tex]

Answer:

4417

i think because

mv^2/r is centripetal force

Answer: The second one? C.

Answer:

B. - Voltage is decreased by local transformers.

Explanation:

edge 2021  beep boop

Answer:

Police officer

Explanation:

Because police officers wants to gather information on what happens and question people to know everything. That is what Derick is doing

Answer:

The  correct option is D

Explanation:

From the question we are told that

  The intensity of the first  electromagnetic wave is  [tex]I = 18 \ W/m^2[/tex]

  The amplitude of the electric field is  [tex]E_{max}_1 =A[/tex]

   The intensity of the second electromagnetic wave is  [tex]I = 36 \ W/m^2[/tex]

Generally the an electromagnetic wave intensity is mathematically represented as

       [tex]I = \frac{1}{2} * \epsilon_o * c * E_{max}^2[/tex]

Looking at this equation we see that

     [tex]I \ \ \alpha \ \ E^2_{max}[/tex]

=>  [tex]\frac{I_1}{I_2} = [ \frac{ E_{max}_1}{ E_{max}_2} ] ^2[/tex]

=>   [tex]E_{max}_2 = \sqrt{\frac{x}{y} } * E_{max}_1[/tex]

=>  [tex]E_{max}_2 = \sqrt{\frac{36}{18} } * E[/tex]        

=>  [tex]E_{max}_2 = \sqrt{2 } E[/tex]