A box with mass of 2 kg is pushed directly horizontally over a horizontal surface (with friction) at a constant speed of 10 m/s. The force of the push is 60 N. How much thermal energy is generated pushing the box a distance of 15 m

Answer: D

Explanation:

Given that a car travels from point A to B in 3 hours and returns back to point A in 5 hours. Points A and B are 150 miles apart along a straight highway.

From point A to B

The speed = distance / time

Where

Distance = 150 mile

Time = 3 hours

Substitute the values into the formula

Speed = 150/3 = 50 mile/ hours

From Point B to Point A

Distance = 150 miles

Time = 5 hours

Where speed = distance/ time

substitute all the parameters into the formula

Speed = 150/5 = 30 mph

Therefore, The car travels at 50 mph for the first half and 30 mph for the second half.

The correct answer is option D

Answer:

usa

Explanation:

Answer:

Work, in physics, measure of energy transfer that occurs when an object is moved over a distance by an external force at least part of which is applied in the direction of the displacement. ... To express this concept mathematically, the work W is equal to the force f times the distance d, or W = fd.

Answer:

a) Strings of guitar (being played)

b) Heart-beat in a healthy person

c) Motion of an apple falling from a tree

Explanation:

a) The motion of the string of a guitar being played is the only motion involving simple harmonic motion.

b) All the other motions are circular motion except the heart beat in a healthy person, which is periodic.

c) The motion of an apply falling from a tree is the only motion under the complete influence of gravity from the onset till the end.

Answer:

Explanation:

The series three. The series 3 will cut the voltage into 1/3. The current will also be lower because of the voltage drop.

The parallel circuit will not cut the voltage and the current will be tripled because each bulb is taking out exactly what it needs.

As an aside, house wiring would be a nightmare if the bulbs were connected in series. If one bulb burned out, you'd have to find it in the dark because they all would go out.

Answer:

The tension in the rod as the ball moves through the bottom circle is 9.8 N

Explanation:

When the ball is released from rest, the centripetal force equals the weight of the ball. So mv²/r = mg where m = mass of ball = 0.5 kg, v = speed of ball, r = radius of vertical circle = length of rod = 0.5 m and g = acceleration due to gravity = 9.8 m/s²

v = √gr = √9.8 m/s² × 0.5 m = √4.9 = 2.21 m/s

Now at the bottom of the circle T - mg = mv²/r where T = tension in the rod

T = m(g + v²/r)

= m(g + (√gr)²/r)

= m(g+ gr/r)

= m(g + g)

= 2mg

= 2 × 0.5 kg × 9.8 m/s²

= 9.8 N

So, the tension in the rod as the ball moves through the bottom circle is 9.8 N

Answer:

Explanation:

Kaleidoscopes work on the principle of multiple reflections.

The mirrors reflect the images of objects inside, creating a symmetrical pattern.

When you look at your reflection in one mirror, you see light that has come from your face and bounced off the mirror.

Answer:

Explanation:

(a) It is given that Joseph jogs on a straight road of 300m in a time interval of 2 minutes and 30 seconds, which is equal to 150seconds. Therefore, when Joseph jogs from point A to point B, he covers a distance of 300m in time of 150seconds. Hence, his average speed is 300m/150s=2ms^−1. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m.

Hence, his average velocity is 300m/150s=2ms^−1

(b) Then it is given that he turns back and points B and jogs on the same road but in the opposite direction for a time interval for 1 minute and covers a distance of 100m.If we consider the whole motion of Joseph, i.e. from point A to point C, then he covers a total distance of 300m+100m=400m. And he covers this total distance in a time interval of 2.5min+1min=3.5min=210s.

Therefore, his average speed for this journey is 400m210s=1.9ms−1.

For the same journey is displacement is equal to the distance between the points A and C,i.e. 300m−100m=200m.

Hence, his average velocity for this case is 200m/210s=0.95ms^−1

Answer:

The velocity of the stone is 2.57 m/s.

Explanation:

Given that

Height = 0.337 m

We need to calculate the velocity of the stone

Using equation of motion

[tex]v^2-u^2=2gh[/tex]

Where, v = velocity of stone

u = initial velocity

g = acceleration due to gravity

h = height

Put the value into the formula

[tex]v^2-0=2\times9.8\times 0.337[/tex]

[tex]v=\sqrt{2\times9.8\times0.337}[/tex]

[tex]v=2.57\ m/s[/tex]

Hence, The velocity of the stone is 2.57 m/s.

Answer:

a system is a set of some things which helps the good happenings in ousr day to day life. It also helps the astrophysisists to find the planets with a system

Answer:

hlo

Explanation:

plzz mark me as brainlest

i can do anything

Answer:

D, photosynthesis

Explanation:

Answer:

first part the skater goes down a constant slope ramp, initially he has Newton's second law

pply Newton's third law, the normal is the reaction to the support of the body on the surface

the ramp shoots off.  axis becomes zero and therefore with Newton's first law its speed

Explanation:

It is the description of this movement let's write Newton's laws.

* The first law that a body goes at constant speed or zero if the sum of the external forces is zero

* the second law is F = m a

* The third law states that the forces act in pairs of equal magnitude and opposite direction, one applied to each body.

Let's apply these laws to our case

In the first part the skater goes down a constant slope ramp, initially he has Newton's second law when he accelerates from the initial velocity of zero to a terminal velocity.

The expression for this is

             Wₓ - fr = ma

             W sin θ - μ W cos θ = m a

             W = mg

             g (sin θ - μ cos) = a

the value of the coefficient of kinetic friction depends on the condition of the surface, dry, wet or muddy

This is Newton's second law

On the Y axis, which is perpendicular to the ramp we have

            N- [tex]W_{y}[/tex] = 0

If we apply Newton's third law, the normal is the reaction to the support of the body on the surface, note that it can be different from the weight.

In the second part when he is on the ramp.

In the ramp the skater enters with a speed v, suppose that the ramp has an incline so that the skater can jump, in this case the angle is positive with respect to the axis x

In this case the analysis is similar to the previous one

Newton's second law gives the acceleration of the skater, who when he reaches the end of the ramp shoots off.

 At this point the force in the x (horizontal) axis becomes zero and therefore with Newton's first law its speed this axis remains constant and the force in the y axis is the force of gravity and has an acceleration that changes if velocity according to Newton's second law

Answer:look at explanations

Explanation:

Answer:

Explanation:

Given the following :

Temperature (Th) of hot reservoir = 30°C (30 +273) = 303K

Temperature (Tc) of cold reservoir = 0°C (273K)

Quantity (Q) of heat transferred from hot reservoir = 400 J

Total change in entropy (ΔStotal) :

ΔStotal = ΔShot + ΔScold

ΔS = Q/T

Hot reservoir is losing 400J of heat ;

Q = - 400 J

ΔShot = Q/Th

ΔShot = - 400/303

ΔShot = - 1.32 J/K

ΔScold = Q/T

ΔScold = 400 / 273

ΔScold = 1.47 J/K

ΔStotal = ΔShot + ΔScold

ΔStotal = - 1.32 + 1.47

ΔS total = 0.15 J/K

Answer:

-400/303 = -1.32

400/273 = 1.47

-1.32 + 1.47 =

.15 J/K

Explanation:

a p e x

Answer:

option a is correct

Explanation:

water ∠iron∠aluminium∠mercury

water density =1.0000

iron =7.487

aluminium=2.07

mercury=13.59

Answer:

A. 112 J

Explanation:

KE = ½mv² = ½(0.14)40² = 112 J

Answer:

Balanced forces

Explanation:

Answer:

its balance force

Explanation:

Answer: The bonds can shift because valence electrons are held loosely and move freely.

Explanation:

Answer:

4.5 x 10^4 x -2 x 10^-6 = -0.09N

Explanation:

-0.09N

Answer:

a) [tex]N_{p}[/tex]/[tex]N_{s}[/tex] = 2

b) [tex]I_{in}[/tex]/[tex]I_{out}[/tex] = 0.5

c) A Kenyan travelling in the united states will now use the output terminal of the transformer in Kenya as the input terminal in the United States, to step up the voltage from 120 V to 240 V for his devices

Explanation:

Kenya's standard voltage [tex]V_{p}[/tex] = 240 V

America's standard voltage [tex]V_{s}[/tex] = 120

using the transformer relationship

[tex]V_{p}[/tex]/[tex]V_{s}[/tex] = [tex]N_{p}[/tex]/[tex]N_{s}[/tex]

substituting values, we have

240/120 =  [tex]N_{p}[/tex]/[tex]N_{s}[/tex]

[tex]N_{p}[/tex]/[tex]N_{s}[/tex] = 2

b) The power input must be equal to the power output

[tex]I_{in}[/tex][tex]V_{in}[/tex] = [tex]I_{out}[/tex][tex]V_{out}[/tex]

where [tex]I_{in}[/tex] = input current

[tex]V_{in}[/tex] = input voltage = 240 V

[tex]I_{out}[/tex] = output current

[tex]V_{out}[/tex] = output voltage = 120 V

Transposing the above equation, we get

[tex]I_{in}[/tex]/[tex]I_{out}[/tex] = [tex]V_{out}[/tex]/[tex]V_{in}[/tex]

[tex]I_{in}[/tex]/[tex]I_{out}[/tex] = 120/240 = 0.5

c) A Kenyan travelling in the united states will now use the output terminal of the transformer in Kenya as the input terminal in the United States, to step up the voltage from 120 V to 240 V for his devices.

Answer:

True

Explanation:

Thats is true since it cannot be a vector because speed only gives a magnitude, not a direction as well.

Answer:

D!!!!!

Explanation:

A hypothesis is a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

Answer:

D. An educated guess about the outcome of an experiment.

Explanation:

Hypothesis is an educated guess about the outcome of an experiment.

Hope this helps ;) ❤❤❤

Explanation:

the force acting perpendicularly on unit area of surface

A pressure of one Newton per square meter .. The SI unit of 1 Pascal pressure is 1 Newton per square metre .

Answer: The keywords to input into the blank spaces were omitted which are ; fragments, increases, decreases, opaque, raises, molecular, protostar, gravitational, thermal.

Please find the answers for the blank spaces in the explanation column

Explanation:

1. The first stage of stellar formation is the assembly (or formation) of a_PROTOSTAR______ . 2. Stars form in MOLECULAR clouds. 3. When a cloud collapses, it FRAGMENTS into smaller and smaller pieces till those pieces reach stellar masses. 4. As the density increases, the fragments become_OPAQUE______ , which___RAISES_____ the temperature of the cloud and inhibits further fragmentation. 5. The __FRAGMENTS_____then condense into rotating globs of gas that serve as stellar embryos. 6. During this stage the surface temperature INCREASES_______ and luminosity__INCREASES_______ despite decreasing size. 7. The central temperature and pressure increase as the GRAVITATIONAL potential energy is converted to energy due to THERMAL contraction.

The above describes the evolution or formation of stars which begins with the collapse of a molecular cloud by gravitational force, this collapse cause the molecular cloud to fragment with the release of heat --Gravitation potential energy causing an increased temperature and pressure of the newly condensing  fragment with increasing luminosity known as a Protostar.

The line graph showing the temperature change over time of a liquid before it boils has an upward-sloping trend as heat is applied until it reaches its boiling point, with fluctuations due to heat transfer rate changes.

Heat transfer rate refers to the amount of heat energy transferred per unit of time between two objects or substances that are at different temperatures. It is a measure of how quickly heat is transferred between two objects or substances and is influenced by factors such as the temperature difference between the objects, the thermal conductivity of the materials, the surface area in contact, and the type of heat transfer mechanism involved (conduction, convection, or radiation). Heat transfer rate is often expressed in units of watts or BTUs per unit of time (e.g., watts/second or BTUs/hour).

Here in the Question,

The shape of the line graph that shows the temperature change over time of the liquid before it starts to boil is generally an upward-sloping line. As heat is applied to the liquid, its temperature will increase gradually until it reaches its boiling point. The rate of temperature increase may not be constant, and there may be some fluctuations due to factors such as changes in the rate of heat transfer.

Therefore, the trend of the line graph will be upward-sloping until the liquid reaches its boiling point.

To learn more about the boiling point of water click:

https://brainly.com/question/30462611

#SPJ2

Answer:

Option B. 2 A.

Explanation:

The following data were obtained from the question:

Resistance 1 (R1) = 1 Ω

Resistance 2 (R2) = 2 Ω

Resistance 3 (R3) = 3 Ω

Potential difference (V) = 12 V.

Current through the 3 Ω (I3) =?

Next, we shall determine the total resistance of the circuit.

This can be obtained as follow:

Resistance 1 (R1) = 1 Ω

Resistance 2 (R2) = 2 Ω

Resistance 3 (R3) = 3 Ω

Total resistance (R) =.?

R = R1 + R2 + R3

R = 1 + 2 + 3

R = 6 Ω

Next, we shall determine the current flowing in the circuit.

This can be obtained as follow:

From ohm's law,

Voltage (V) = current (I) x resistance (R)

V = IR

Potential difference (V) = 12 V.

Resistance (R) = 6 Ω

Current (I) =?

V = IR

12 = I x 6

Divide both side by 6

I = 12/6

I = 2 A.

Since the circuit is in series connection, therefore, the same current will flow through each resistor.

Therefore, the current through the the 3 Ω load is 2 A.

Answer:

number 6 is wrong

the answer is pesticides

2.combines are used for harvesting or threshing.so number 2 is wrong

at least you tried

Explanation:

there is no such thing as weedicides

Answer:

1. True

2.True

3.False

4. True

5. True

6.False

7.False

8.True

9.False

10.False

Answer

Resistivity R = K * L / A    where resistivity is constant for material, L the length of the material and A the area of the material

K = R * A / L     where R is the resistance of the material

Answer:

find the sum of the inital and final velocitys and divide by 2 to find the average

Answer:

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