the two ropes are used to vertically lower a 255 kg piano from exactly 4 m form a seocnd sotry window to the ground how much work is done by each of the three forces

Answer:

c

Explanation:

Liquid plastic is frozen in a physical change that increases its volume,it can be known about the plastic that Its mass will remain the same, therefore the correct answer is option C.

Anything which has mass and occupies space is known as matter ,mainly there are four states of matter solid liquid gases, and plasma.

These different states of matter have different characteristics according to which they vary their volume and shape.

It is known about plastic that its mass will remain the same when liquid plastic is frozen, by increasing its volume.

Liquid plastic is frozen in a physical change that increases its volume,it can be known about the plastic that Its mass will remain the same,  therefore the correct answer is C.

To earn more about the matter here,refer to the link;

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Answer:

Explanation:

That is an amazing fact.

The minus sign is what you have to pay attention to. The earth has a mass of 100 times that of Saturn. As someone on here once noted, Saturn has such a low density that it would float in water.

The answer is D

Answer:

[tex]E_0=0.173N/C[/tex]

Explanation:

From the question we are told that:

Power [tex]P=50kw=>50*10^3w[/tex]

Distance [tex]d=10km=10000m[/tex]

Generally the equation for Intensity is mathematically given by

[tex]I=\frac{P}{4\pi d^2} w/m^2[/tex]

[tex]I=\frac{50*10^3}{4 \pi 10000^2} w/m^2[/tex]

[tex]I=3.98*10^{-5}w/m^2[/tex]

Generally Intensity is also

[tex]I=\frac{1}{2}cE_0^2e[/tex]

Where

[tex]e=8.854*10^{-12}Nm^2/c^2[/tex]

Therefore

[tex]E_0=\sqrt{\frac{2I}{c *e}}[/tex]

[tex]E_0=\sqrt{\frac{2*3.98*10^{-5}}{3*10^8 *8.854*10^{-12}}}[/tex]

[tex]E_0=0.173N/C[/tex]

Answer:

a)  [tex]F=9.2*10^{-6}N/m^2[/tex]

b)  [tex]a=5.4*10^{-4}m/s[/tex]

c)  [tex]v=46.65m/s[/tex]

Explanation:

From the question we are told that:

Intensity I= 1.36 kW/m2=>1360W/m

b)Average mass per square meter m = 0.170 kg

c) [tex]T=24hrs[/tex]

a)

Generally the equation for force per square meter  is mathematically given by

[tex]F=\frac{2E}{C}[/tex]

[tex]F=\frac{2*1360}{3*10^8}[/tex]

[tex]F=9.2*10^{-6}N/m^2[/tex]

b)

Generally the equation for force  is mathematically given by

F=ma

Therefore

[tex]a=\frac{F}{m}[/tex]

[tex]a=\frac{9.2*10^{-6}N/m^2}{0.0170}[/tex]

[tex]a=5.4*10^{-4}m/s[/tex]

c)

Generally the Newton's equation for Motion is mathematically given by

[tex]v=u+at[/tex]

[tex]v=0+5.4*10^{-4}m/s*(24*3600)[/tex]

[tex]v=46.65m/s[/tex]

Answer:

Following are the complete solution to the given question:

Explanation:

In this question, before tug they are at rest, thus their initial momentum is 0 [tex]\pi=0[/tex], according to the law of conservation [tex]p_f=0[/tex] thus both should move in the opposite direction whose sum of the momentums is equaled to zero as there is no friction they will continue to move with their velocities until their collision. Its collision doesn't happen it will continue up to an infinite distance.

The motion of both you and your partner depends on the tension in the rope.

We must note that frictional force is the force that acts between two surfaces in contact with each other. The frictional force depends on the nature of the surfaces in contact.

Now, since there is no friction between your leg and the ice. The motion of both you and your partner depends on the tension in the rope.

Learn more about tension force: https://brainly.com/question/1195122

Answer:

the cost of running the stereo is $211.2

Explanation:

Given;

cost of electricity, = 12.00$/kWh

power consumed by the stereo system, P = 220 W

duration of the power consumption, t = 8 hours

number of days, = 10 days

total time of the power consumption = 8 hours x 10 = 80 hours

power consumed in kW = 220 W / 1000 = 0.22 kW

Energy consumed = 0.22 kW x 80 h = 17.6 kWh

The cost of using 17.6 kWh

= 17.6 x $12

= $211.2

Therefore, the cost of running the stereo is $211.2

Answer:

The total length of wire is 0.24 m.

Explanation:

Number of turns, N = 270

magnetic field, B = 0.48 T

frequency, f = 60 Hz

rms value of emf = 120 V

maximum value of emf, Vo = 1.414 x 120 = 169.68 V

let the area of square is A and the side is L.

The maximum emf is given by

Vo = N B A w

169.68 = 270 x 0.48 x A x 2 x 3.14 x 60

A = 3.5 x 10^-3 m^2

So,

L = 0.0589 m

Total length of wire, P = 4 L = 4 x 0.0589 = 0.24 m

Answer:

The block will not move.

Explanation:

We'll begin by calculating the frictional force. This can be obtained as follow:

Coefficient of friction (µ) = 0.6

Mass of block (m) = 3 Kg

Acceleration due to gravity (g) = 10 m/s²

Normal reaction (R) = mg = 3 × 10 = 30 N

Frictional force (Fբ) =?

Fբ = µR

Fբ = 0.6 × 30

Fբ = 18 N

From the calculations made above, the frictional force of the block is 18 N. Since the frictional force (i.e 18 N) is bigger than the force applied (i.e 14 N), the block will not move.

Answer:

0.023 Ohms

Explanation:

Given data

Length= 2.8m

radius= 1.03mm

current I= 1.35 A

voltage V= 0.032V

We know that from Ohm's law

V= IR

Now  R= V/I

Substitute

R= 0.032/1.35

R= 0.023 Ohms

Hence the resistance is 0.023 Ohms

Answer:

Lubrication

Explanation:

People oil/lubricate bicycle chains because the chain turns around the cogs and rub together so this help with friction.

Hope this helps :)

Answer:

The method of reducing friction are :

i) In moving parts of machine friction can be reduced by using a ball bearing between the moving surfaces

ii) The bodies of aeroplane ,ship ,boat etc are made streamlined to reduce friction.

iii) Friction can be reduced by polishing rough surfaces. For example : carrom boards are highly polished to reduce friction.

I hope this help you:)

(C)

Explanation:

[tex]E = hf = (6.626×10^{-34}\:\text{J•s})(8.0×10^{15}\:\text{Hz})[/tex]

[tex]= 5.3×10^{-18}\:\text{J}[/tex]

Answer:

It's D

Explanation:

It's from alvs

Answer:

b) - 3.3 J

Explanation:

Given;

mass, m = 2 kg

initial extension of the spring, x = 6 cm = 0.06 m

The weight of the mass on the spring;

W = mg

where;

g is acceleration due to gravity = 9.81 m/s²

W = 2 x 9.81

W = 19.62 N

The spring constant is calculated as;

W = kx

k = W/x

k = 19.62 / 0.06

k = 327 N/m

The work done by the spring when it is extended to an additional 10 cm;

work done = force x distance

distance = extension, x =  10 cm = 0.1 m

The work done by the spring opposes the applied force by acting in opposite direction to the force.

W = - Fx

W = - (kx) x

W = - kx²

W = - (327) x (0.1)²

W = - 3.27 J

W ≅ - 3.3 J

Therefore, the work done by the spring by opposing the applied force is -3.3 J

Answer:

An object in either state of equilibrium must have no net force acting on it.

Explanation:

Answer: An object in either state of equilibrium must have no net force acting on it.

Explanation:

Answer:

opposite direction

Explanation:

An electric field is defined as a physical field which surrounds the electrically charged particles that exerts force on the other particles on the field.

Now when an electron or a negatively charged particle enters a uniform electric field, the electric forces acts on the negatively charged particles and it forces the particle to move in the direction which is opposite to the direction of the field. In an uniform electric field, the field lines are parallel.

Answer:

Explanation:

negatively charged particle is placed inside uniform electric field

The force on the charge due to the electric field is

F = q E

when the charge is negative so the force on the charge is opposite to the direction of electric field.

The electric field is opposite to the force.

Answer:

Explanation:

An impulse results in a change of momentum.

The impulse is the product of a force and a distance. This will be represented by the area under the curve

a) W = ½(4.00)(3.00) = 6.00 J

b) W = (11.0 - 4.00)(3.00) = 21.0 J

c) W = ½(17.0 - 11.0)(3.00) = 9.00 J

d) ASSUMING the speed at x = 0 is in the direction of applied force

½(3.00)(v₄²) = ½(3.00)(0.450²) + 6.00

v₄ = 2.05 m/s

½(3.00)(v₁₇²) = ½(3.00)(0.450²) + 6.00 + 21.0 + 9.00

v₁₇ = 4.92 m/s

If the initial speed is NOT in the direction of applied force, the final speed will be slightly less in both cases.

Answer:

The speed at B is 16.18 ft/s .

Explanation:

Speed at A, u = 11 ft/s

Speed at C, v' = 18 ft/s

Time from A to C = 5 s

Time from B to C = 1.3 s

Let the speed of car at B is v.

Let the acceleration is a.

From A to B

Use first equation of motion

v = u + a t

18 = 11 + a x 5

a = 1.4 ft/s^2

Let the time from A to B is t' .

t' = 5 - 1.3 = 3.7 s

Use first equation of motion from A to B

v = 11 + 1.4 x 3.7 = 16.18 ft/s  

Answer:

The net electric field at the midpoint is 6.85 x 10^7 N/C.

Explanation:

q = − 8.3 μC

q' = + 7.8 μC

d =  9.2 cm

d/2 = 4.6 cm

The electric field due to the charge q at midpoint is

[tex]E = \frac{k q}{r^2}\\\\E = \frac{9\times 10^9\times 8.3\times 10^{-6}}{0.046^2}\\\\E = 3.53\times 10^7 N/C[/tex] leftwards

The electric field due to the charge q' at midpoint is

[tex]E' = \frac{k q}{r^2}\\\\E' = \frac{9\times 10^9\times 7.8\times 10^{-6}}{0.046^2}\\\\E' = 3.32\times 10^7 N/C[/tex]

The resultant electric field at mid point is

E'' = E + E' = (3.53 + 3.32) x 10^7 = 6.85 x 10^7 N/C

Explanation:

the car will be brought back

Explanation:

For air, n1 = 1.00003; for water, n2 = 1.3330

Given: θ2 = 30 degrees, then

θ1 = arcsin [(n2/n1) sin θ2]

= arcsin [(1.3330/1.0003) sin (40)]

= 58.93 degrees

Note that since, in this example, light is traveling from a medium of higher density (water; n2 = 1.3330) to a medium of lower density (air; n1 = 1.0003), then n2 > n1, and the angle of refraction (θ1) is larger than the angle of incidence (θ2), thus the light bends away from the normal (in this example, the vertical) as it leaves the water and enters the air.

Answer:

In sof the friction with the nylon is very small and the current with the line e is largeummary

Explanation:

When we rub the shoes against the carpet, static electricity is produced, when you touch the metal knob you close the circuit and the current can circulate to three of the body, the value of this current is of the order of micro volts, for which a small discharge, the power that circulates through the body is very small of the order of 0.005 A

When you touch the power line, the voltage may be small, but the amount of current that can generate them is of the order of tens of amps, the electric shock is much greater per location.

In general there is a rule that if the body resumes more than P = 4000W the discharge could be fatal.

In sof the friction with the nylon is very small and the current with the line e is largeummary, the difference is that the current at the stop , so the paper that passes through the body is large and can be dangerous.

In contact with metal doorknob, get a mild shock  while with power line of same voltage, fatal the body as the amount of current is more.

When the two materials are rubbed each other, then the electric charged generated between them.

This charging of materials, due to the rubbing of two materials against each other, is called the charging by friction.

It is easy to produce a potential difference of several thousand volts between the body and the floor by scuffing your shoes across a nylon carpet.

In this case, the potential difference may be higher, but the value of current is very low. Thus, when the body touches a metal doorknob, it will get a mild shock.

Now, in another case, the contact with a power line of comparable voltage would probably be fatal. This is because in the power line the amount of current is much higher.

Hence, in contact with metal doorknob, get a mild shock  while with power line of same voltage, fatal the body as the amount of current is more.

Learn more about the charging by friction here;

https://brainly.com/question/8418256

Answer:

............................................

Explanation:

Answer:

Q at the center of the distribution.

Explanation:

Answer:

12

Explanation:

i agree the answer is 12 because the acceleration is given by the difference in the velocity divided by the time taken

a=v-u/t

60-0/5

=12m/s²

I hope this helps

Answer:

a)  p₀ = 1.2 kg m / s,  b) p_f = 1.2 kg m / s,  c)   θ = 12.36, d)  v_{2f} = 1.278 m/s

Explanation:

For this exercise we define a system formed by the two balls, which are isolated and the forces during the collision are internal, therefore the moment is conserved

a) the initial impulse is

         p₀ = m v₁₀ + 0

         p₀ = 0.6 2

         p₀ = 1.2 kg m / s

b) as the system is isolated, the moment is conserved so

        p_f = 1.2 kg m / s

we define a reference system where the x-axis coincides with the initial movement of the cue ball

we write the final moment for each axis

X axis

         p₀ₓ = 1.2 kg m / s

         p_{fx} = m v1f cos 20 + m v2f cos θ

         p₀ = p_f

        1.2 = 0.6 (-0.8) cos 20+ 0.6 v_{2f} cos θ

         1.2482 = v_{2f} cos θ

Y axis  

        p_{oy} = 0

        p_{fy} = m v_{1f} sin 20 + m v_{2f} cos θ

        0 = 0.6 (-0.8) sin 20 + 0.6 v_{2f} sin θ

        0.2736 = v_{2f} sin θ

we write our system of equations

         0.2736 = v_{2f} sin θ

         1.2482 = v_{2f} cos θ

divide to solve

         0.219 = tan θ

          θ = tan⁻¹ 0.21919

          θ = 12.36

let's look for speed

            0.2736 = v_{2f} sin θ

             v_{2f} = 0.2736 / sin 12.36

            v_{2f} = 1.278 m / s

the longer the wavelength, lower the frequency. In the same manner, shorter the wavelength, higher will be the frequency.

Answer:

velocity is the answer of this question.

Answer:

Velocity is the right answer ok

Answer: 26.84 m/s

Explanation:

Given

Original frequency of the horn [tex]f_o=228\ Hz[/tex]

Apparent frequency [tex]f'=246\ Hz[/tex]

Speed of sound is [tex]V=340\ m/s[/tex]

Doppler frequency is

[tex]\Rightarrow f'=f_o\left(\dfrac{v+v_o}{v-v_s}\right)[/tex]

Where,

[tex]v_o=\text{Velocity of the observer}\\v_s=\text{Velocity of the source}[/tex]

Insert values

[tex]\Rightarrow 246=228\left[\dfrac{340+v_o}{340-0}\right]\\\\\Rightarrow 366.84=340+v_o\\\Rightarrow v_o=26.8\ m/s[/tex]

Thus, the speed of the car is [tex]26.84\ m/s[/tex]