Does the air in a room or water in a pot have to be at a certain temperature to create convection? Yes or No? and Explain why?

Answer:

1 m/s

Explanation:

Using law of conservation of momentum

m1v1 + m2v2 = (m1 + m2)vf , where

m1 = mass of object at rest, 20 kg

v1 = initial velocity of object at rest, 0 m/s

vf = final velocity of the bodies

m2 = mass of object in motion, 10 kg

v2 = initial velocity of object in motion, 3 m/s

On substituting, we have

(20 * 0) + (10 * 3) = (20 + 10) vf

0 + 30 = 30 vf

vf = 30 / 30

vf = 1 m/s

Therefore, the velocity of the bodies after hitting each other is 1 m/s

Answer:

Following are the solution to this question:

Explanation:

Law:

[tex]\to \theta= 180^{\circ}- 50^{\circ}- 25^{\circ}[/tex]

      [tex]= 180^{\circ}- 75^{\circ}\\\\= 105^{\circ}[/tex]

[tex]\to \frac{T_{L}}{\sin (90+50)}= \frac{T_{R}}{\sin (25+90)}=\frac{1400}{\sin (105)}[/tex]

[tex]\to T_L=931.65 \ pounds \\\\ \to T_R=1313.59 \ pounds \\\\[/tex]

First:

5 cm = 0,05 m

Now, the formula:

F = k * (qq') / r²

Replacing:

F = 9x10⁹ * (55x10⁸ * 1x10⁷) / 0,05²

F = 9x10⁹ * (5,5x10¹⁶ / 2,5x10⁻³)

F = 9x10⁹ * 2,2x10¹⁹

F = 1,98x10²⁹

The force between the charges is 1,98x10²⁹ Newtons.

Answer:

Explanation:

Let the right index finger be the pivot, the balanced ruler is shown in the diagram attached to this answer.

a. The forces present are:

i. The weight of the ruler, W, which acts upwards at the point of pivot.

ii. The reaction, R, of the right index finger on the ruler which acts upwards.

b. According to the principle of equilibrium, the total forces acting upwards must be equal to the total forces acting downwards.

So that,

R = W ................. 1

ii. The sum of clockwise moment must be equal to the sum of anticlockwise moment.

Since the ruler is balanced at the mid-point (6 inch), then;

R x 0 = w x 0 = 0 ............... 2

This implies that no moment is experienced by the ruler balanced on the right index finger. Therefore, the ruler is said to be in a state of equilibrium.

Answer:

a) Newton proposed three laws to explain the motion of things.

b) bodies are in motion the kinetic moment   is preserved,

c) entropy

Explanation:

In this exercise you are asked to explain various concepts of physics

a) Newton proposed three laws to explain the motion of things.

* The first law or inertia states that a body in an inertial system (without acceleration) remains stationary or with constant velocity if the sum of the forces is zero

* The second law states that the force (interaction) is proportional to the masses and the acceleration of the bodies

        F = m a

* The third law or action and reaction, says that the forces always go in pairs, that is, if a body interacts with a body 2, and body 2 will also interact with body 1, with the same force but with the opposite direction, each force is applied to a body

b) when bodies are in motion the kinetic moment

          L = I w

it is preserved, if it does not interact with the outside.

The quantity I called the moment of inertia is I = m r²

In this case

in the initial instant with outstretched arms

     L = I₀ w₀

in the final moment. By shrinking your arms

    [tex]L_{f}[/tex] = I_{f} w_{f}

as the body does not interact with another

     L₀ = L_{f}

     I₀ w₀ = I_{f} w_{f}

     w_{f} = [tex]\frac{I_{o} }{I_{f} }[/tex]  w₀

we substitute

      w_{f} = \frac{r_{o} }{r_{f} }^2 w₀

as the distance of the arms extended is greater than when they are retracted (r₀>  [tex]r_{f}[/tex]), the final angle speed increases

c) This is an application of the concept of entropy that establishes that disorder is the most probable state of a system, which is why the cave increases its disorder or entropy over time since by not fixing things, they are increasingly dispersed

Answer:

number 2 down is: safetygoggles

Explanation:

no space

Lab safety personal protective equipment should always be put on when in the lab, and lab equipment are what scientists for lab work

The words for the lab safety and lab equipment puzzle are:

1. Test tube rack

2. Splash goggles

3. Fire extinguisher

4. Balance scale

5. Closed heel

6. Deluge shower

7. Waft

8. Pipette

9. Proctor

10. Meter stick

11. Bunsen burner

12. Cleanup

13. Beaker tongs

14. Measuring cylinder

15. Funnel

16. Trash bin

17. Hot plate

18. Beaker

19. Lab apron

20. Fire blanket

Learn more about lab equipment here:

https://brainly.com/question/13142279

https://brainly.com/question/13164015

https://brainly.com/question/17391361

Answer:

The Dimension of mass is [F T v⁻¹] and Dimension of energy is [F T v]

Explanation:

(i) We know that,

Force = mass × acceleration

= mass × velocity/time

⇒ mass = force × time ÷ velocity

or. [mass] = [force] [time] ÷ [velocity]

= [F] [T] ÷ [v]

∴ [mass] = [F T v⁻¹]

(ii) Dimensions of energy are same as the dimensions of kinetic energy

∴ Energy = [ ½mv²] = [m] [v]²

= [F T v⁻¹] [v]²

Energy = [F T v]

Thus, The Dimension of mass is [F T v⁻¹] and Dimension of energy is [F T v]

-TheUnknownScientist

Explanation:

fvt-1 = mass

ftv = energy

Answer:

if the frequency is double, the wavelength is only half as long

Explanation:

Considering the definition of wavelength, frequency and propagation speed, if the wavelength is doubled, the frequency is reduced by half.

In a periodic wave the wavelength (λ) is the physical distance between two points from which the wave repeats itself. That is, the wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

The frequency (f) is a measure of the number of cycles or repetitions of the wave per unit of time. Its unit is s⁻¹ or hertz (Hz).

The wavelength and its frequency are related from the speed at which the wave travels. The propagation speed (v) is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave's disturbance propagates along its displacement. So, the speed expression is:

v=λ×f

This indicates that the higher the frequency, the shorter the wavelength and the lower the frequency, the longer the wavelength.

All electromagnetic waves propagate in a vacuum at a constant speed of 300,000,000 m/s, the speed of light. Then, since an inversely proportional relationship is established between the frequency and the wavelength, if the wavelength is doubled, the frequency is reduced by half.

In summary, if the wavelength is doubled, the frequency is reduced by half.

Learn more:

Answer:

It is because the room is occupied with stuffs.

Explanation:

In a well furnished room there are things

like bed, cupboard, wardrobe and other stuffs, So they act as absorbing materials.

They absorb sound and do not give a chance to resounds.

Answer:

Its a Universal Force

Explanation:

Answer:

Even though the cross-sectional area of each capillary is extremely small compared to that of the large aorta, the total cross-sectional area of all the capillaries added together is about 1,300 times greater than the cross-sectional area of the aorta because there are so many capillaries

Explanation:

Answer:

The answer is "effective stress at point B is 7382 ksi "

Explanation:

Calculating the value of Compressive Axial Stress:

[tex]\to \sigma y =\frac{F}{A} = \frac{4 F}{( p d ^2 )} = \frac{(4 x ( - 40000 \ lbf))}{[ p \times (1 \ in)^2 ]} = - 50.9 \ ksi \\[/tex]

Calculating Shear Transverse:

[tex]\to \frac{4v}{ 3 A} = \frac{4 (75 \ lbf + 25 \ lbf)}{ \frac{3 ( lni)^2}{4}}[/tex]

        [tex]= \frac{4 (100 \ lbf)}{ \frac{3 ( lni)^2}{4}} \\\\ = \frac{400 \ lbf)}{ \frac{3 ( lni)^2}{4}} \\\\= 0.17 \ ksi[/tex]

[tex]= R \times 200 \ in - P \times 100 \ in = 12500 \ lbf \times\ in[/tex]

[tex]\to \sigma' =[ s y^2 +3( t \times y^2 + t yz^2 )] \times \frac{1}{2}\\\\[/tex]

       [tex]= [ (-50.9)^2 +3((63.7)^2 +(0.17)^2 )] \times \frac{1}{2}\\\\=[2590.81+ 3(4057.69)+0.0289]\times \frac{1}{2}\\\\=[2590.81+12,173.07+0.0289] \times \frac{1}{2}\\\\=14763.9089\times \frac{1}{2}\\\\ = 7381.95445 \ ksi\\\\ = 7382 \ ksi[/tex]

Answer:

(a) The kinetic energy at A is 6.875 J.

(b) The speed at point B is 5.26 m/s.

(c) The total work done on the particle as it moves from A to B is 0.725 J.

Explanation:

Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.

Kinetic energy is defined as the amount of work necessary to accelerate a body of a given mass and at rest, until it reaches a given speed. Once this point is reached, the amount of accumulated kinetic energy will remain the same unless a change in speed occurs or the body returns to its state of rest by applying a force.

Kinetic energy is represented by the following formula:

Ec = ½ *m*v²

Where Ec is kinetic energy, which is measured in Joules (J), m is mass measured in kilograms (kg), and v is velocity measured in meters over seconds (m/s).

(a) In this case, you know:

Replacing:

Ec = ½ *0.55 kg*(5 m/s)²

and solving you get:

Ec= 6.875 J

The kinetic energy at A is 6.875 J.

(b) In this case, you know:

Replacing:

7.6 J = ½ *0.55 kg*v²

and solving you get:

[tex]v=\sqrt{\frac{7.6 J}{\frac{1}{2}*0.55 kg } }[/tex]

v= 5.26 m/s

The speed at point B is 5.26 m/s.

(c)  The total work done on the particle as it moves from A to B is the difference between the work done at the end point (point B) and the work done at the start point (point A). Considering that work is equal to kinetic energy, then:

Work= Ec at point B - Ec al point A= 7.6 J - 6.875 J

Work= 0.725 J

The total work done on the particle as it moves from A to B is 0.725 J.

Explanation:

General relativity is a theory of space and time. ... The central idea of general relativity is that space and time are two aspects of spacetime. Spacetime is curved when there is matter, energy, and momentum resulting in what we perceive as gravity. The links between these forces are shown in the Einstein field equations.

Answer:

bowling was one of the first racially integrated sports because bowling alleys were primarily located in urban areas. Racial integration was inevitable since it was promoted by US Armed Forces during 1940s and its image as sport for the common man made it a choice of activity for Americans!!

Explanation:

Answer:

The  correct option is b

Explanation:

From the question we are told that

    The resistance of the first resistor is  [tex]R_1 = 39 \ \Omega[/tex]

     The resistance of the second resistor is  [tex]R_2 = 56 \ \Omega[/tex]

      The capacitive reactance of the first capacitor is [tex]jX_{c_1 } = 80 \ \Omega[/tex]

       The capacitive reactance of the first capacitor is [tex]jX_{c_2 } = 40 \ \Omega[/tex]

Generally given that the resistors are connected in parallel , their equivalent resistance is  

            [tex]R_e = R_1 +R_2[/tex]

=>         [tex]R_e = 39 + 56[/tex]

=>         [tex]R_e = 95 \ \Omega[/tex]

Generally given that the capacitors are connected in parallel , their equivalent capacitive reactance  is  

          [tex]jX_e = jX_{c_1} + jX_{c_2}[/tex]

=>       [tex]jX_e = 80 + 40[/tex]

=>       [tex]jX_e = 120[/tex]

Hence the impedance of the circuit is  

         [tex]Z = R_e - jX_e[/tex]        

=>      [tex]Z = 95 - j120[/tex]          

Generally from the impedance equation , the total used resistance is  

       [tex]R_e = 95 \ \Omega[/tex]

Answer:

The correct answer is B)

Explanation:

When a wheel rotates without sliding, the straight-line distance covered by the wheel's center-of-mass is exactly equal to the rotational distance covered by a point on the edge of the wheel.  So given that the distances and times are same, the translational speed of the center of the wheel amounts to or becomes the same as the rotational speed of a point on the edge of the wheel.

The formula for calculating the velocity of a point on the edge of the wheel is given as

[tex]V_{r}[/tex] = 2π r / T

Where

π is Pi which mathematically is approximately 3.14159

T is period of time

Vr is Velocity of the point on the edge of the wheel

The answer is left in Meters/Seconds so we will work with our information as is given in the question.

Vr = (2 x 3.14159 x 1.94m)/2.26

Vr = 12.1893692/2.26

Vr = 5.39352619469

Which is approximately 5.39

Cheers!

Answer:

Conductors- copper, aluminum, gold, and silver.

Insulators- glass, air, plastic, rubber, and wood.

Explanation:

Answer: 5 conductors are copper, aluminum, gold, iron, and silver and 5 insulators are glass, air, plastic, rubber, and wood.

Answer:

a) The work done by the applied force is 1500 joules.

b) The kinetic energy of the block after 10 seconds is 1200 joules.

c) The magnitude of the force of friction is 3 newtons and its direction is against motion.

d) 300 joules of energy are lost during motion.

Explanation:

a) Since the object has a constant mass, on which a constant horizontal force is exerted. The work done by the force ([tex]W[/tex]), measured in joules, is defined by the following expression:

[tex]W = F\cdot \Delta x[/tex] (1)

Where:

[tex]F[/tex] - Force, measured in newtons.

[tex]\Delta x[/tex] - Distance, measured in meters.

If we know that [tex]F = 15\,N[/tex] and [tex]\Delta x = 100\,m[/tex], then the work done by the force exerted on the object is:

[tex]W = (15\,N)\cdot (100\,m)[/tex]

[tex]W = 1500\,J[/tex]

The work done by the applied force is 1500 joules.

b) At first we need to calculate the net acceleration of the object ([tex]a[/tex]), measured in meters per square second. By assuming a constant acceleration, we use the following kinematic formula:

[tex]\Delta x = v_{o}\cdot t +\frac{1}{2}\cdot a\cdot t^{2}[/tex] (2)

Where [tex]v_{o}[/tex] is the initial velocity of the object, measured in meters per second.

We clear the acceleration within the equation above:

[tex]\frac{1}{2}\cdot a \cdot t^{2} = \Delta x-v_{o}\cdot t[/tex]

[tex]a = \frac{2\cdot (\Delta x - v_{o}\cdot t)}{t^{2}}[/tex]

If we know that [tex]\Delta x = 100\,m[/tex], [tex]v_{o} = 0\,\frac{m}{s}[/tex] and [tex]t = 10\,s[/tex], then the net acceleration experimented by the object is:

[tex]a = \frac{2\cdot \left[100\,m-\left(0\,\frac{m}{s} \right)\cdot (10\,s)\right]}{(10\,s)^{2}}[/tex]

[tex]a = 2\,\frac{m}{s^{2}}[/tex]

By the 2nd Newton's Law, we construct the following equation of equilibrium under the consideration of a friction force acting against the motion of the object:

[tex]\Sigma F = F - f = m\cdot a[/tex] (3)

Where:

[tex]F[/tex] - External force exerted on the object, measured in newtons.

[tex]f[/tex] - Kinetic friction force, measured in newtons.

If we know that [tex]F = 15\,N[/tex], [tex]m = 6\,kg[/tex] and [tex]a = 2\,\frac{m}{s^{2}}[/tex], the kinetic friction force is:

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

[tex]f = 15\,N-(6\,kg)\cdot \left(2\,\frac{m}{s^{2}} \right)[/tex]

[tex]f = 3\,N[/tex]

The work done by friction ([tex]W'[/tex]), measured in joules, is:

[tex]W' = f\cdot \Delta x[/tex] (4)

[tex]W' = (3\,N) \cdot (100\,m)[/tex]

[tex]W' = 300\,J[/tex]

And the net work experimented by the object is:

[tex]\Delta W = 1500\,J - 300\,J[/tex]

[tex]\Delta W = 1200\,J[/tex]

By the Work-Energy Theorem we understand that change in translational kinetic energy ([tex]\Delta K[/tex]), measured in joules, is equal to the change in net work. That is:

[tex]\Delta K = \Delta W[/tex] (5)

If we know that [tex]\Delta W = 1200\,J[/tex], then the change in translational kinetic energy is:

[tex]\Delta K = 1200\,J[/tex]

The kinetic energy of the block after 10 seconds is 1200 joules.

c) The magnitude of the force of friction is 3 newtons and its direction is against motion.

d) The energy lost by the object is equal to the work done by the force of friction. Therefore, 300 joules of energy are lost during motion.

Answer:

A. 28.42 m/s

B. 41.21 m

Explanation:

From the question given above, the following data were obtained:

Time (t) to reach the maximum height = 2.90 s

Initial velocity (u) =?

Maximum height (h) =?

A. Determination of the initial velocity of the ball.

Time (t) to reach the maximum height = 2.90 s

Final velocity (v) = 0 m/s (at maximum height)

Acceleration due to gravity (g) = 9.8 m/s²

Initial velocity (u) =?

v = u – gt (since the ball is going against gravity)

0 = u – (9.8 × 2.9)

0 = u – 28.42

Collect like terms

0 + 28.42 = u

u = 28.42 m/s

Thus, the initial velocity of the ball is 28.42 m/s

B. Determination of the maximum height reached by the ball.

Final velocity (v) = 0 m/s (at maximum height)

Acceleration due to gravity (g) = 9.8 m/s²

Initial velocity (u) = 28.42 m/s

Maximum height (h) =?

v² = u² – 2gh (since the ball is going against gravity)

0² = 28.42² – (2 × 9.8 × h)

0 = 807.6964 – 19.6h

Collect like terms

0 – 807.6964 = – 19.6h

– 807.6964 = – 19.6h

Divide both side by – 19.6

h = – 807.6964 / – 19.6

h = 41.21 m

Thus, the maximum height reached by the ball is 41.21 m

Answer:

Thus, the object is accelerating to the left

Explanation:

The Net Force

The net force is the result of adding all the forces as vectors acting on a body.

[tex]\vec F=\vec F_1+\vec F_2+...+\vec F_n[/tex]

Each vector can be expressed in its rectangular components Fx and Fy, and the sum is the sum of the rectangular components separately.

Second Newton's law gives the relation between the net force and the acceleration of the body:

[tex]\vec F = m.\vec a[/tex]

We can see the acceleration is a vector with the same direction as the net force.

The diagram shows two vertical forces and two horizontal forces.

The vertical forces are acting in opposite directions and with the same magnitude, thus they cancel out, leaving zero net force in the y-axis.

The horizontal forces are opposite and with different magnitudes. Since the force acting to the left (F3) has a greater magnitude than the force acting to the right (F4), there is a net force directed to the left with a magnitude of 60 N - 20 N = 40 N

Thus, the object is accelerating to the left

Answer:

The frequency [tex]f = 0.8048 \ Hz[/tex]

Explanation:

From the question we are told that

    The mass of the object is  [tex]m = 19 \ kg[/tex]

      The spring constant is  [tex]k = 486 \ N/ m[/tex]

Generally the maximum frequency is mathematically represented as  

        [tex]f = \frac{1}{2 \pi } * \sqrt{ \frac{k}{m } }[/tex]

=>     [tex]f = \frac{1}{2 * 3.142 } * \sqrt{ \frac{486}{ 19 } }[/tex]

=>     [tex]f = 0.8048 \ Hz[/tex]

Answer:

Just 3

Explanation:

I believe the other two are incorrect

Explanation:

Given that,

Distance covered, d = 40 m

Time, t = 9.5 s

Final velocity, v = 2.75 m/s

(a) Let u be the original speed of the truck. We can find it using first equation of motion.

[tex]v=u+at\\\\2.75=u+2.75\times 9.5\\\\2.75-26.125=u\\\\u=-23.375\ m/s[/tex]

(b) Acceleration = rate of change of velocity

[tex]a=\dfrac{v-u}{t}\\\\a=\dfrac{2.75-(-23.375)}{9.5}\\\\=2.75\ m/s^2[/tex]

So, the original speed is -23.375 and acceleration is 2.75 m/s².

Answer:

Fr = 55 [N]

Explanation:

We must perform a free body diagram to understand the forces acting on the couch. In the attached image we see the force that Jack exerts just like that of Rob acting in the same direction.

We must perform a summation of force on the X-axis, to determine the resulting force.

∑Fx = Fr

Fr = 30 + 25

Fr = 55 [N]

Answer:

[tex]F=3.93\times 10^{-7}\ N[/tex]

Explanation:

Mass of student 1, m₁ = 79 kg

Mass of student 2, m₂ = 93.5 kg

The students are 1.12 m apart, d = 1.12 m

We need to find the force of the gravitational attraction between them. The force of gravitational force is given by :

[tex]F=G\dfrac{m_1m_2}{r^2}\\\\F=6.67\times 10^{-11}\times \dfrac{79\times 93.5}{(1.12)^2}\\\\=3.93\times 10^{-7}\ N[/tex]

So, the force of gravitational attraction between them is [tex]3.93\times 10^{-7}\ N[/tex]. Hence, the correct option is (B).

Answer:

25000N

Explanation:

distance travelled(d)=500m

force(f)=20N

Power=0.4KW=0.4×1000Watt=400watt

Then,Time(T)=?

Now,

Power(P)=W/T

400=F×D/T.(w=f×d)

or, 400=20×500/T

or, 400=10000/T

or, T=10000/400

or,T=25 sec

Therefore,time taken=25 sec