The graph below shows the number of sunspots observed between 1750 and 2000.


Based on the graph, which of these periods most likely witnessed the greatest increase in solar radiation

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:

hlo

Explanation:

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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.

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Answer:

usa

Explanation:

Answer:

A. 112 J

Explanation:

KE = ½mv² = ½(0.14)40² = 112 J

Answer:

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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:

Standard weight: We calculate the standard weight as follows: G = L * mweight, where L is the length of the beam calculated as the difference between the extreme points of the beam body along the direction of the beam axis, taking into account all features except holes.

Explanation:

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Answer:

Explanation:

Given that:

For a first order instrument with a sensitivity of .4 mV/K

constant c  = 25 ms = 25 × 10⁻³ s

The initial temperature [tex]T_1[/tex] = 273 K

The final temperature [tex]T_2[/tex] = 473 K

The initial volume = 0.4 mV/K × 273 K = 109.2 V

The final volume =  0.4 mV/K × 473 K =  189.2 V

the instrument’s response as a function of time for a sudden temperature increase can be computed as follows:

Let consider y to be the function of time i.e y(t).

So;

y(t) = 109.2  + (189.2 - 109.2)( 1 - [tex]\mathbf{e^{-t/c}}[/tex])mV

y(t) = (109.2 +  80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

Plot the response y(t) as a function of time.

The plot of y(t) as a function of time can be seen in the diagram  attached below.

What are the units for y(t)?

The unit for y(t) is mV.

Find the 90% rise time for y(t90) and the error fraction,

The 90% rise time for y(t90) is as follows:

Initially 90% of 189.2 mV = 0.9 ×  189.2 mV

=  170.28 mV

170.28 mV = (109.2 +  80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

170.28 mV - 109.2 mV = 80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

61.08 mV =  80 ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

0.7635  mV = ( 1 - [tex]\mathbf{e^{t/25\times 10^{-3}}}[/tex])) mV

t = 1.44 × 25  × 10⁻³ s

t = 0.036 s

t = 36 ms

The error fraction = [tex]\dfrac{189.2-170.28 }{189.2}[/tex]

The error fraction = 0.1

The error fraction = 10%

Answer:

True

Explanation:

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

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:

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) [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:

the final statements the correct one is. The second

The iron piece exerts a force of 1 N on the magnet in the opposite direction

Explanation:

In this exercise they give us the force exerted by a magnet on an iron bar and ask us the force that the iron bar exerts on the magnet. We can see that these are action and reaction forces, which by Newton's third law must be of equal magnitude and opposite direction, each applied to one of the bodies.

the final statements the correct one is. The second

The iron piece exerts a force of 1 N on the magnet in the opposite direction

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.

Explanation:

It is given that,

The distance covered by a body along the x-axis is given by :

[tex]x=2t^3+5t^2+t[/tex]

t is in seconds and x is meters

Speed of the body is given by :

[tex]v=\dfrac{dx}{dt}\\\\v=\dfrac{d(2t^3+5t^2+t)}{dt}\\\\v=6t^2+10t+1[/tex]

At t = 0,

[tex]v=6(0)^2+10(0)+1=1\ m/s[/tex]

At t = 2 s,

[tex]v=6(2)^2+10(2)+1=45\ m/s[/tex]

So, the average speed in a time interval from t= 0s and t=2s is 45 m/s.

Answer:

The meaning of grit in psychology is a positive, non-cognitive trait based on an individual's perseverance of effort combined with the passion for a particular long-term goal or end state.

Answer:

(B) Parachutes

Explanation:

Air resistance works to slow down trains and airplanes, so it isn't desirable.  Air resistance also causes pendulums to slow and stop.

Parachutes need air resistance to slow a person's fall.  So air resistance is desirable here.

Answer:

B i answered it it it

Explanation:

Answer:

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

Explanation:

-0.09N

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:

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:

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

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.

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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:

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.

The work done by the force on the block is:

[tex]W=135.41*3=406.23 \: J[/tex]

The direction of motion here is in the y-direction, so we need to find the component of the force in this direction.

Using trigonometric functions:

[tex]F_{y}=Fsin(37)[/tex]

This component is in the positive y-direction.

Now, there is a friction force between the block and the wall, so we need to find the friction force.

[tex]F_{f}=\mu N[/tex]

Where:

Let's use the first Newton's Law to get F.

F(y) is upward (+) and F(f) and the weight is downward (-).

[tex]F_{y}-F_{f}-W=0[/tex]

[tex]F_{y}-F_{f}=mg[/tex]

Factoring F in the left side:

[tex]F(sin(37)-\mu cos(37))=mg[/tex]    

[tex]F=\frac{mg}{sin(37)-\mu cos(37)}[/tex]  

[tex]F=\frac{5*9.81g}{sin(37)-(0.3*cos(37))}[/tex]  

[tex]F=135.41\: N[/tex]    

Therefore, the work done will be:

[tex]W=Fd[/tex]  

[tex]W=135.41*3=406.23 \: J[/tex]  

You can learn more about work definition here:

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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:

0.632456 m/s

Explanation:

After 1 hour, 80 g decays to 40 g.

After another hour (total 2 hours), 40 g decays to 20 g.

After another hour (total 3), 20 g decays to 10 g.

After one more hour (total 4), 10 g decays to (D) 5 g.

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