If you have 100 kg of each of these substances, which would require the most energy to increase its temperature by 25 Kelvin?

A. Iron
B. Carbon
C. Rubber
D. Air

Answer:

Explanation:

Power = Workdone/Time

Since workdone = Force * distance = mgh

Power = mgh/t

Given

Power = 10watts

speed = 2m/s

Power = Weight * velocity

Substitute

10 = Weight * 2

Weight = 10/2

Weight = 5N

Hence the weight of the object is 5N

Answer:

F = 878.9 N

Explanation:

The electrostatic force of attraction or repulsion is given by Coulomb's Law as follows:

F = kq₁q₂/r²

where,

F = Force pf repulsion between balloons = ?

k = Coulomb's Constant = 9 x 10⁹ N.m²/C²

q₁ = q₂ = magnitudes of 1st and 2nd charge = 0.0025 C

r = distance between balloons = 8 m

Therefore,

F = (9 x 10⁹ N.m²/C²)(0.0025 C)(0.0025 C)/(8 m)²

F = 878.9 N

The magnitude of the electrical force of repulsion between them is F = 878.9 N

Here we use Coulomb's Law

F = kq₁q₂/r²

Here,

F = Force of repulsion

k = Coulomb's Constant = 9 x 10⁹ N.m²/C²

q₁ = q₂ = magnitudes of 1st and 2nd charge = 0.0025 C

r = distance between balloons = 8 m

So,

F = (9 x 10⁹ N.m²/C²)(0.0025 C)(0.0025 C)/(8 m)²

F = 878.9 N

Hence, The magnitude of the electrical force of repulsion between them is F = 878.9 N

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Reflection is when waves bounce off a surface this because I did it in 7th grade was my favorite unit to learn in school.

When two different media come together at an  a wavefront might change direction so that it returns to the first medium, which is known as reflection.

The reflection of light, sound, and water waves are typical examples. According to the law of reflection, the angle at which the wave incident on the surface equals the angle at which it is reflected for specular reflection (such as at a mirror).

Reflection produces echoes in acoustics and is used in sonar. It is crucial to the study of seismic waves in geology. Surface waves in bodies of water are used to observe reflection.

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Answer:

The velocity of Mosquito with respect to earth will be 0.302m/s

Explanation:

V(ma) = 1.10 m/s, east  Velocity of mosquito with respect to air

V(ae) = 1.4 m/s at 35°  Velocity of air with respect to Earth in west of south direction.

Velocity of Mosquito with respect to earth will be  

V(me) = V(ma) + V(ae)

We need to find the mosquito’s speed with respect to Earth in the x direction.

V(x, me) = V(x, ma) + V(x, ae) = V(ma) + V(ae)(cos theta(ae) )

Angle (ae) = –90.0° − 35°=−125°

V(x, me) = 1.10 + (1.4)Cos(-125)

             = 1.10 + 1.4(-0.57)

             = 1.10 -0.798

              = 0.302

So the velocity of Mosquito with respect to earth will be 0.302m/s

Answer:

Answer: B. $0.78.

Explanation:

Cost of Electricity

The rate of the cost of electricity is usually expressed in $/kWh or cents/kWh because the consumption of electricity is measured in Kilowatts-hour.

The local power company charges 5.79 cents/kWh.

We are required to calculate the cost to run a 120 W stereo system for 4 hours per day for 4 weeks.

The total consumption time is 4 hours/day * 7 days/week *4 weeks = 112 hours

The total energy consumed is 120 W * 112 h =13,440 Wh.

Converting to kWh: 13,440 Wh/1,000 = 13.440 kWh.

Finally, we multiply by the cost rate: 5.79 cents/kWh * 13.440 kWh = 77.8 cents/100 = $0.78.

Answer: B. $0.78.

Answer:

False

Explanation:

Since it is on the bus, it would not move forward because the outside acceleration cannot be considered.

Answer:

I think A

Explanation:

because it dosn't have enough tools

Answer: The correct answer is graph A.

Explanation:

See Khan Academy.

Answer: it C

Explanation:

Answer:

1) 4000Joules

2) 25%

3) 320N

Explanation:

A block and tackle consisting of 5 pulleys is used to raised a load of 400N through a height of 10m.If the work done against friction is 100j.

Calculate;

1)The work done by the effort

2)The efficiency of the system

3)The effort applied

1) Workdone by the effort is the work input = Load * distance moved by the Load

Workdone by the effort = 400 * 10

Workdone by the effort = 4000Joules

2) Efficiency = Work output/Work input * 100

Work output = work done against friction = 100 Joules

Efficiency = 100/4000 * 100

Efficiency = 10000/4000

Efficiency  = 25%

Hence the Efficiency of the system is 25%

3) Using the efficiency formula:

efficiency = MA/VR * 100

Velocity ratio = 5

MA = Load/Effort

efficiency = (L/E)/5 * 100

25 = 400/E/5 * 100

25/100 = 400/5E

0.25 = 400/5E

0.25 * 5E = 400

1.25E = 400

E = 400/1.25

E = 320N

hence the effort applies is 320N

Answer:

I took the science quiz and Its A

Explanation:

HOPE THIS HELPS!

The iron-nickel alloy melts due to hot temperatures. This statement best explains why Earth’s outer core is in liquid form

The Earth's outer core is the second innermost layer, located between the inner core and the mantle. It contains mostly iron and nickel, which- due to lower pressure than existing at the inner core- are in the liquid form. The outer core, about 2,200 kilometers (1,367 miles) thick, is mostly composed of liquid iron and nickel  because of the high temperature. However, the intense pressure, which increases towards the inner core, dramatically changes the melting point of the nickel–iron, making it solid. The  iron and nickel alloy of the outer core is very hot, between 4,500° and 5,500° Celsius (8,132° and 9,932° Fahrenheit).

The outer core is a liquid alloy of mainly iron and nickel. The reason why the core is metal is that the heavy metals sank to the center while the Earth was cooling. The mantle which lies above the core is made of molten rock

correct option is a) The iron-nickel alloy melts due to hot temperatures.

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Answer:

78.4m

Explanation:

In these situations, vertical and horizontal components need to be considered separately;

So, horizontal speed is irrelevant since we are talking about vertical height, i.e. the height of the cliff;

But, the fact that the speed is horizontal is relevant because this means the vertical speed initially is 0m/s;

The downwards movement of the ball is due to gravity, which is 9.8m/s²;

The time is given as 4.0s from the top of the cliff to the bottom;

We know the acceleration, time and initial speed so we can use this kinematic equation to solve for distance:

s = ut + ¹/₂at²

s = displacement (/distance)

u = initial vertical velocity = 0

t = time (time taken for the ball to fall) = 4

a = acceleration (downwards) = 9.8

Substitute these values into the equation to get the distance:

s = 0(4) + ¹/₂(9.8)(4)²

s = 78.4m

Answer:

D

Explanation:

Answer:

Direct current

Explanation:

Because it cannot reverse, and it's optimum for usage by electric home appliances.

Unlike Alternating current which reverses, and can cause electric appliances to burn out.

Answer:

The solid sphere.

Explanation:

The moment of inertia for hollow sphere is larger, thereby having a greater resistance to motion. Thus the solid sphere will have greater speed.

Answer:

The solid sphere

Explanation:

So when comparing the spheres, both spheres have the same density and have the same radius which would they are the same size so the only factor to vary them is mass. The solid sphere is filled and thus heavier compared to the hollow sphere which has lighter air. As a result, the solid sphere will be pulled down by gravity more and reach the bottom first.

Answer:

B. [tex]5\,\frac{m}{s^{2}}[/tex] South

Explanation:

The correct statement is:

A washing machine is being dragged with a starting force of 380.8 N to the South, but this is reduced by friction. If the mass of the washing machine is 37 kg  and the coefficient of friction is 0.54, what was the Net acceleration experienced by the washing machine?

The net force of the washing machine moving on the horizontal ground is equal to the external force minus the friction force, where the normal force from the ground on the washing machine is equal to its weight. The free body diagram of the washing machine is presented below. The equation of equilibrium associated with the acceleration of the washing machine is:

[tex]\Sigma F = P -\mu_{k}\cdot m \cdot g = m\cdot a[/tex] (1)

Where:

[tex]P[/tex] - External force exerted on the washing machine, measured in newtons.

[tex]\mu_{k}[/tex] - Kinetic coefficient of friction, dimensionless.

[tex]m[/tex] - Mass, measured in kilograms.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

[tex]a[/tex] - Net acceleration of the washing machine.

If we know that [tex]P = 380.8\,N[/tex], [tex]m = 37\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]\mu_{k} = 0.54[/tex], then the net acceleration experienced by the washing machine is:

[tex]a = \frac{P}{m}-\mu_{k}\cdot g[/tex]

[tex]a = \frac{380.8\,N}{37\,kg}-(0.54)\cdot \left(9.807\,\frac{m}{s^{2}} \right)[/tex]

[tex]a = 4.996\,\frac{m}{s^{2}}[/tex]

The correct answer is B.

Answer:

1.97 * 10^8 m/s

Explanation:

Given that:

n = 1.52

Recall : speed of light (c) = 3 * 10^8 m/s

Speed (v) of light in glass:

v = speed of light / n

v = (3 * 10^8) / 1.52

v = 1.9736 * 10^8

Hence, speed of light in glass :

v = 1.97 * 10^8 m/s

Answer:

d

Explanation:

the spring depends on gravity and friction

Answer:

Tailed star

Explanation:

Tailed star

Answer:

The radius of the circle made by the person on the merry go round is 74.55 meters

Explanation:

The given parameters are;

The force the merry go round exerts on the rider = 1000 N

The time it takes the merry go round to make one complete revolution = 15 seconds

The weight of the person = 750 N

The radius of the circle made by the person on the merry go round = r

We have;

[tex]F_c = \dfrac{m \cdot v^2}{r} = m \cdot \omega ^2 \cdot r[/tex]

Where;

m = The mass of the person

v = The velocity of the person

[tex]F_c[/tex] = The centrifugal force acting on the person = 1,000 N

r = The radius of the circle made by the person on the merry go round

ω = Angular velocity = 2·π/15 rad/s

We have;

The mass of the person = The weight/(The acceleration due to gravity, g)

∴ The mass of the person = 750/9.81 ≈ 76.45 kg

By substituting the calculated and known values into the equation for  the centripetal force, we have;

[tex]F_c[/tex] = m × ω² × r

1000 = 76.45 × (2·π/15)² × r

r = 1000/(76.45 × (2·π/15)²) = 74.55 m

The radius of the circle made by the person on the merry go round = r = 74.55 m.

Explanation:

answers.................

Explanation:

dimension are used for

1 we check the homogeneity of a physical equation

2 drive a possible formula for a physical problem

3 To find dimensions of physical constants or coefficients.

Answer:

50 N

Explanation:

Since the refrigerator doesn’t move, that means the force of friction equals the amount of force the child exerts on the fridge. If the friction force were greater than the force by the child, the fridge would start accelerating towards the child. If it were less than the force the child exerted, the fridge would start accelerating away from the child. Therefore, the net force must be 0, in this case, the friction force is equal to the force the child exerted, for it to stay at rest (as Newton’s First Law stated).

I hope this helps! :)

Answer: Two objects sliding against each other.

Explanation:

The friction between the two surfaces converts kinetic energy into heat.

Answer:

33,333.33 N

Explanation:

Given that :

Initial kinetic energy = 500,000 J

Final kinetic energy = 100,000 J

Using the relation :

Force * time = change in momentum (Newton's law)

Force (F) * 0.12 = (500,000 - 100,000)

0.12F = 400,000 J

Force = (400,000 J) / 0.12s

Force = 33333.333

Force = 33,333.33 N

Answer:

cold

Explanation:

Answer:

The answer is B

Explanation:

Trust

Answer:

Because even though our eyes have a huge dynamic range (ability to pick out details in sharply lit and lesser lit areas simultaneously) than any camera, there's a limit.

When there's strong sunlight, your pupils contract and let less light in, which makes the shadows look darker.

When it's cloudy, your pupils widen and let more light in, which makes the shadows look less dark.

Do some experiments with a camera and you'll soon get the hang of it.

NOTE: Also test HDR (high dynamic range) photography, where the camera takes three or more pictures in quick succession, with different exposure settings, and combines them to get the most detail of both bright and dark areas. The result is more or less what we percieve.

Answer:

Distance is the length of the path taken by an object whereas displacement is the simply the distance between where the object started and where it ended up.

Explanation:

Hope this helps! Good Luck on the rest of your assignments! :)

Answer:

Distance is quite literally the total amount of distance you have covered. Displacement is the total displacement from your origin. For example, if you were to move 5m north then 2m south, your total displacement from your origin would be 3m north.

A 40 N force would move a load 9.875 m high when 395 J of work is done on the load.

The total amount of energy transferred when a force is applied to move an object through some distance

The work done is the multiplication of applied force with displacement.

The SI  unit of work done by an object is Joules.

IJ is the work done when a force of 1 N displaces an object by 1 m .

Work Done = Force * Displacement

For the given problem Force =40N and work done = 395 J

By using the above formula

Work Done = Force * Displacement

395 j = 40 N × height

height =9.875 m

Thus a 40 N force supported by a work done of 395 J moves the load up to 9.875 m height

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