Electromagnetic waves are classified as longitudinal waves.


Please select the best answer from the choices provided

T
F

sorry i think so i dont exactly know i am sorry

Explanation:

As a certain amount of water is cooled from room temperature until it reaches 4 °C, its volume drops. The density reduces as the volume increases below 4 °C. Therefore, water's greatest density occurs at 4 degrees Celsius.

Water has an unusual trait called anomalous expansion, which causes it to enlarge rather than compress when the temperature drops from 4 °C to 0 °C, and it becomes less dense.

At temperatures not far below zero degrees Celsius, water ice is unique for having low coefficients of static and dynamic friction that range from 0.04-0.02, but as the temperature drops, these numbers rise.

Therefore, When a metal sheet's temperature rises by one degree, its coefficient of area expansion is calculated as the increase in surface area per unit of original surface area.

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Answer:

Nervous system and immune system

Explanation:

The nervous system is involved because you immediately jumped away, that ur brain and nerves initiating the fight or flight response. The immune system is involved because the tack most likely pierced your skin, so your immune system needs to work to make sure the wound does not get infected.

Answer:

Acceleration, a = 0.65m/s² due North.

Explanation:

Given the following data;

Initial velocity = 12mi/hr

Final velocity = 25mi/hr

Time = 9 secs

To find the acceleration;

First of all, we would convert miles per hour to meters per seconds.

[tex] Initial \; velocity = \frac {12 * 1609.344}{60*60} = \frac {19312.128}{3600} = 5.37m/s [/tex]

[tex] Final \; velocity = \frac {25 * 1609.344}{60*60} = \frac {40233.6}{3600} = 11.18m/s [/tex]

Now to find the acceleration;

Mathematically, acceleration is given by the equation;

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

Substituting into the equation, we have;

[tex]a = \frac{11.18 - 5.37}{9}[/tex]

[tex]a = \frac{5.81}{9}[/tex]

Acceleration, a = 0.65m/s² due North.

None can.

A clinical thermometer only measures temperatures above +30°C.

Mercury and alcohol are both frozen solid at -50°C.

Answer:

Explanation:

The velocity can be found by using the formula

[tex]v = \sqrt{ \frac{2k}{m} } \\ [/tex]

k is the kinetic energy

m is the mass

From the question we have

[tex]v = \sqrt{ \frac{2 \times 4116}{4200} } \\ = 1.4[/tex]

We have the final answer as

Hope this helps you

Answer:

The speed of the lift is 1.4 m/s

Explanation:

Kinetic Energy

Is the type of energy of an object due to its motion. It's proportional to the square of the speed and the mass.

The equation 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

The kinetic energy is expressed in Joules (J)

It's given the mass of the lift as m=4,200 kg and its kinetic energy K=4,116 J. To calculate the speed (magnitude of velocity), we solve the formula for v as follows:

[tex]\displaystyle v=\sqrt{\frac{2k}{m}}[/tex]

[tex]\displaystyle v=\sqrt{\frac{2*4,116}{4,200}}[/tex]

[tex]\displaystyle v=\sqrt{1.96}[/tex]

v = 1.4 m/s

The speed of the lift is 1.4 m/s

Answer:

Ffriction = 217.7[N]

Explanation:

First, we must find the mass of the box, we must remember that the weight is defined as the product of the mass by acceleration.

[tex]w=m*g[/tex]

where:

w = weight [N] (units of Newtons)

m = mass [kg]

g = gravity acceleration = 9.81 [m/s²]

[tex]1300=m*9.81\\m=132.51[kg][/tex]

Now we must use Newton's second law, which tells us that the sum of forces is equal to the product of mass by acceleration.

∑F = m*a

where:

∑F sum of forces

m = mass = 132.51[kg]

a = acceleration = 1.3[m/s²]

We must know that the forces that act are the horizontal force that moves the box and the friction force in the negative direction that acts against the movement.

Now replacing:

[tex]390-f_{friction}=132.51*1.3\\390-172.26=f_{friction}\\f_{friction}=217.7[N][/tex]

Answer:

20m/s due east

Explanation:

Given parameters:

Displacement eastward  = 200m

Time  = 10s

Unknown:

Velocity  = ?

Solution:

Velocity is the displacement divided by time;

    Velocity  = [tex]\frac{displacement}{time}[/tex]  

 Velocity  = [tex]\frac{200}{10}[/tex]    = 20m/s due east

Answer:

Explanation:

A) Large: As she opens her parachute, she begins to displace a large volume of air. This leads to a Large air resistance

B) increase, weight: As she falls, the air resistance force increases. Now there is a force acting in opposite directions to her weight.

C)Weight, Decelerate: The skydiver has only the downward force of her weight pulling down on her, so she starts to decelerate

D) Weight, Upward, Resultant:

Her weight is now equal to the upward force from the ground. Her resultant  force is then zero

E) Increases, same, constant,  resultant, terminal:

As she accelerates faster, the air resistance force increases. It is now the same as her weight. She now moves at a constant speed because the resultant force acting on her is zero. She is now at her terminal velocity.

F) Increases, same, constant, terminal:

As she decelerates, the air resistance force on her parachute increases until it is the same as her weight. She is now moving with a constant speed until she hits the ground - a new slower terminal velocity

Answer:

  160 W

Explanation:

Power is the ratio of work to time:

  (1600 J)/(10 s) = 160 J/s = 160 W

Answer:

8 J and 2 J

Explanation:

Given that,

Mass of the rubber ball, m = 1 kg

Initial speed of the rubber ball, u = 4 m/s (in east)

Final speed of the rubber ball, v = -2 m/s (in west)

We need to find the kinetic energy of the ball before it hits the wall, the kinetic energy of the ball after it bounces off the wall.

Initial kinetic energy,

[tex]K_i=\dfrac{1}{2}mv^2\\\\K_i=\dfrac{1}{2}\times 1\times (4)^2\\\\K_i=8\ J[/tex]

Final kinetic energy,

[tex]K_f=\dfrac{1}{2}mv^2\\\\K_f=\dfrac{1}{2}\times 1\times (2)^2\\\\K_f=2\ J[/tex]

So, the initial kinetic energy is 8 J and the final kinetic energy is 2 J.

The kinetic energy of the ball after it bounces off the wall is 2.0 Joules.

The kinetic energy of an object is the energy that is in motion or performing work. It can be expressed by using the formula:

[tex]\mathbf{K.E = \dfrac{1}{2}mv^2}[/tex]

The Kinetic energy of the ball after the collision and when it bounces off the wall is computed as:

[tex]\mathbf{K.E = \dfrac{1}{2} \times 1 \times 2.0^2}[/tex]

K.E = 2.0 Joules

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Answer:

I think A= 5M/S is answer

Answer:

1m/s²

Explanation:

Given parameters:

Initial velocity  = 2m/s

Final velocity  = 4m/s

Time of chase  = 2s

Unknown:

Acceleration = ?

Solution:

Acceleration is the rate of change of velocity with time;

 A = [tex]\frac{v - u }{t}[/tex]  

A is the acceleration

v is the final velocity

u is the initial velocity

t is the time taken

      A  = [tex]\frac{4 - 2}{2}[/tex]   = 1m/s²

Answer:

12 km/hr

Explanation:

Speed= Distance/Time

Answer:

12km/h

Explanation:

average speed= Distance covered /time taken

average speed=2km/20minutes

=but 1 minutes is 60 seconds

=2km/60minutes

=12km/h

Answer:

the types of gas the car is given

Explanation:

All three cars are identical and have different gas in each car so she is trying to determine how each car will react with different gasoline.

Explanation:

600 ÷ 60 = 10

1500 ÷ 10 = 150 minutes

I don't know how you should express the answer in:

So it's either 150 minutes or 2 hours and 30 minutes.

(This is kind of like mathematics, not physics)

Answer:

480m/s²

Explanation:

Acceleration is the change in velocity of a body with respect to time;

Acceleration = change in velocity/change in time

change in velocity = 29,500 - 24,000

change in velocity= 5,500

Change in time = 55 - 5

change in time = 50secs

Substitute into the formula;

spaceships acceleration = 24000/50

spaceships acceleration = 480 m/s²

Hence the spaceships acceleration is 480m/s²

Answer:

there is not enough information

Answer: B

"Ball 1 at 0.21 m/s left, Ball 2 at 0.22 m/s left"

Answer:I think it’s D

Explanation:

Conduction needs direct touch to transfer

Answer:

9800Nm⁻²

Explanation:

Given parameters:

Dimensions of the water tank = 6m x 4m x 4m

Density of water  = 1000kgm⁻³

Gravity  = 9.8m/s²  

Unknown:

Pressure exerted by the water at the base of the dam  = ?

Solution:

The pressure exerted by the water is given as:

  Pressure  = density of water x acceleration due to gravity x height of water

The height of the water here is half = 1m

Pressure  = 1000 x 9.8 x 1 = 9800Nm⁻²

Answer:

Density is the mass of an object divided by its volume. ... Density often has units of grams per cubic centimeter ... Density is not something that is directly measured.

Explanation:

given

mass (m) = 315 g

length (l) = 7 cm

width (b) = 3 cm

height (h) = 5 cm

Now

volume (v) = l * b * h

V = 7 * 3 * 5

V = 105 cm³

Density (d) = ?

We know

density is defined as mass per unit volume so

d = m / v

d = 315 / 105

d = 3 g/cm³

Therefore density = 3 g/cm³

Note

If the question is asked to write in SI unit of density then u have to write the unit of density as kg/m³

Hope it will help :)

Answer:

It's 4m/s

Explanation:

V = u _ at, at u = 44m/s

44 + [-4]10

4m/s

Velocity of sound travels faster in solids than in liquids, and faster in liquids than in gases because "the density of solids is higher than that of liquids, meaning that the particles are closer together."

Answer:

Explanation:

Due to the fact that sound is caused by vibrations, it's more noticeable in liquid because the vibrations may cause ripples in the liquid

Answer:

The new period of oscillation is D) 3.0 T

Explanation:

Simple Pendulum

A simple pendulum is a mechanical arrangement that describes periodic motion. The simple pendulum is made of a small bob of mass 'm' suspended by a thin inextensible string.

The period of a simple pendulum is given by

[tex]T=2\pi \sqrt{\frac{L}{g}}[/tex]

Where L is its length and g is the local acceleration of gravity.

If the length of the pendulum was increased to 9 times (L'=9L), the new period of oscillation will be:

[tex]T'=2\pi \sqrt{\frac{L'}{g}}[/tex]

[tex]T'=2\pi \sqrt{\frac{9L}{g}}[/tex]

Taking out the square root of 9 (3):

[tex]T'=3*2\pi \sqrt{\frac{L}{g}}[/tex]

Substituting the original T:

[tex]T'=3*T[/tex]

The new period of oscillation is D) 3.0 T

Answer:

1400 N

Explanation:

Verá, durante el salto mortal, el piloto se mueve en una trayectoria circular y la fuerza que actúa sobre él es una fuerza centrípeta.

Sea la fuerza centrípeta F, la masa del piloto (m) = 70 Kg, el radio (r) = 500 my la velocidad (v) = 360 km / hr * 1000/3600 = 100 m / s

F = mv ^ 2 / r

F = 70 * (100) ^ 2/500

F = 1400 N

Answer:

Sound waves are reflected back

Answer:

39225J

Explanation:

Given parameters:

Mass of water  = 375grams of water

Change in temperature  = 25°C

Specific heat capacity of water  = 4.184J/g°C

Unknown:

Amount of heat absorbed  = ?

Solution:

To solve this problem, we use the expression below:

      H  = m c Ф  

H is the heat absorbed

m is the mass

c is the specific heat capacity

Ф is the change in temperature

  Insert the parameters and solve;

      H  = 375 x 4.184 x (25) = 39225J

Answer:

4048 = 115x/100.

Explanation:

Profit P = (15/100) X x.

P= 15x/100.

15x/100 = 4048- x.

4048 = 15x/100 + x.

4048 = 115x/100.

Answer: Optical test is a test which is used to assess vision and ability of the person to focus on the objects.

Explanation:

The following are the advantages of utilizing plane mirror in optical testing:

1. When a plane mirror is used for testing the image of the test card must be placed at distance equal to the distance of the object.  

2. Larger distance in between the object or test card and viewer is obtained. This can help in determining the exact ability of the eye to focus on objects.

Answer:

30*12=360m,it would travel 360 m.