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Answer:

v = 46.67 km/h

Explanation:

We will use the following formula throughout this numerical:

s = vt

where,

s = distance covered

v = speed

t =  time taken

FOR FIRST 30 km:

s = 30 km

v = 30 km/h

t = t₃₀ = ?

Therefore,

30 km = (30 km/h)(t₃₀)

t₃₀ = (30 km)/(30 km/h)

t₃₀ = 1 h

FOR TOTAL 100 km:

s = 100 km

v = 40 km/h (Average Speed)

t = total time = ?

Therefore,

100 km = (40 km/h)(t)

t = (100 km)/(40 km/h)

t = 2.5 h

FOR LAST 70 km:

s = 70 km

t₇₀ = t - t₃₀ = 2.5 h - 1 h = 1.5 h

v = v₇₀ = ?

Therefore,

70 km = v(1.5 h)

v = 70 km/1.5 h

v = 46.67 km/h

Answer:

1.25x10^-19N

Explanation:see attached file pls

Answer:

2 hrs

Explanation:

time = distance ÷ speed

Answer:

Explanation:

the resistance of a electrical device

R = V² / P where V is volt and P is power .

The devices are in parallel so same volt will apply on them

So R₁ = 12² / 32.5 = 4.431 ohm

R₂ = 12² / 2 x 10³ = .072 ohm

when they are in series

Common Current in them = 12 / 4.431 + .072

= 2.6649 A

power consumed by first device when they are in series

= current² x resistance

= 2.6649² x 4.431 = 31.46 W

power consumed by other

= 2.6649² x .072  = .511 W

Explanation:

m = kg. v=m/s. g=m/s^2. h= m

>>1/2mv^2=mgh

>>1/2mv^2=mgh>> kg*(m/s)^2= kg*m/s^2*m

>>1/2mv^2=mgh>> kg*(m/s)^2= kg*m/s^2*m>>kg m^2/s^2=kg m^2/s^2 the fraction 1/2 won't be able to make any changes to to the dimensional expression of energy i.e half of energy is still energy therefore you can neglect the number .

>>kg m^2/s^2=kg m^2/s^2

>>J= J

Answer:

8.8 mT

Explanation:

Current through the conductor = 12.5 A

Magnetic force per unit length on the wire = 0.110 N/m

Recall that the magnetic force per unit length on a current carrying conductor is in a uniform magnetic field is

[tex]\frac{F}{l}= IBsin\alpha[/tex]

where B is the magnetic field magnitude

[tex]I[/tex] is the current in the conductor

α is the angle the conductor makes with the  magnetic field ( since it is perpendicular in this case, α is 90°)

imputing values into the equation, we'll have

0.11 = 12.5 x B x sin 90°

but sin 90° = 1, therefore, we have

0.11 = 12.5B

B = 0.11/12 = 8.8 x 10^-3 T

or rather = 8.8 mT

The amount of lighting on a surface drops to (1/4) of the initial illumination when the distance between a light source and the surface it falls on is doubled.

The amount of light or luminous flux that falls on a surface is known as illumination. It is expressed as lux or lumens per square meter.

The square of the distance has an inverse relationship with the light intensity;

[tex]\rm I = \frac{1}{r^2}[/tex]

Where,

I is the light intensity

r is the distance

Let r is the distance and I is the sound intensity for case 2;

r' = 2r

[tex]\rm I' = \frac{1}{(2r)^2} \\\\ I' = \frac{1}{4r^2} \\\\ I' = \frac{I}{4}[/tex]

When we double the distance between a source of light and the surface on which it falls, the amount of illumination on the surface decreases to(1/2) of the original illumination.

Hence the value of the fraction is 1/4.

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Explanation:

Given,

I = 5 A

V = 240 V

T = 25 mins = 1500 sec

Now,

Energy dissipated = IVT= 5×240×1500 = 1800000 J

Answer:

Explanation:

Friction causes generation of heat and causes increased wear and tear.

The friction is a resistive force and is related to heat energy, so an increase in friction results in the generation of heat, so option D is correct.

Two solid objects cannot roll or slide over one another due to the force of friction. Although frictional forces can be useful, such as the traction needed to walk without slipping, they can also present a large degree of resistance to motion. Automobile engines need about 20% of their power to overcome frictional forces in moving parts.

The fundamental source of friction between metals appears to be the adhesion forces between the contact zones of the surfaces, which are always microscopically uneven. Friction is produced by shearing, these "welded" seams, and the rubbing action of the rougher, tougher surface against the softer, smoother surface.

The friction is a resistive force trying to oppose the force applied As friction is related to heat when we increase the heat, the friction increases, and vice versa.

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Answer:

First, let's think in the vertical problem:

The acceleration will be the gravitational acceleration:

g = 9.8 m/s^2

a = -9.8 m/s^2

For the velocity, we integrate over time:

v(t) = (-9.8 m/s^2)*t + v0

Where v0 is the initial velocity, in this case  v0 = 30m/s.

v(t) =  (-9.8 m/s^2)*t + 30m/s

Now, for the position we integrate again over time, and get:

P(t) = (1/2)*(-9.8 m/s^2)*t^2 + 30m/s*t + p0

Where p0 is the initial position, as the ball is launched from the ground, we can use p0 = 0m

p(t) = (-4.9m/s^2)*t^2 + 30m/s*t

Now, the maximum vertical height is reached when:

v(t) = 0m/s = -9.8m/s^2*t + 30m/s

t = 30m/s/9.8m/s^2 = 3.06s

Now we can evaluate the vertical position in t = 3.06s

p(3.06s) = (-4.9m/s^2)*(3.06)^2 + 30m/s*3.06 = 62m

So, rounding down, the correct option is: C. 60 m

Answer:

210 m

Explanation:

The speed of train 2 relative to train 1 is 15 m/s + 20 m/s = 35 m/s.

It takes 6 seconds for the train to pass, so the length of the train is:

(35 m/s) (6 s) = 210 m

Answer:

θ = 41.8º

Explanation:

This is an internal total reflection exercise, the equation that describes this process is

         sin θ = n₂ / n₁

where n₂ is the index of the incident medium and n₁ the other medium must be met n₁> n₂

        θ = sin⁻¹ n₂ / n₁

let's calculate

       θ = sin⁻¹ (1.00 / 1.50)

       θ = 41.8º

Answer:

2.5 kg/m³

Explanation:

Absolute pressure = gauge pressure + atmospheric pressure

P = Pg + Pa

The gauge pressure caused by the weight of a fluid is called the static pressure.  It is equal to the density of the fluid × acceleration due to gravity × depth of the fluid,

Pg = ρgh

Therefore:

P = ρgh + Pa

300 Pa = ρ (10 m/s²) (8.00 m) + 100 Pa

ρ = 2.5 kg/m³

Answer:

[tex]D.\ 970\ N[/tex]

Explanation:

Given:

Mass of Piano: 99kg

Required:

Calculate its weight

The weight of an object is calculate as thus;

[tex]Weight = Mass\ (m) * Acceleration\ due\ to\ gravity\ (g)[/tex]

[tex]m = 99kg[/tex] and [tex]g = 9.8m/s^2[/tex]

The formula becomes

[tex]Weight = 99kg * 9.8m/s^2[/tex]

[tex]Weight = 970.2\ kgm/s^2[/tex]

[tex]Weight = 970.2\ N[/tex]

[tex]Weight = 970\ N[/tex] Approximated

Hence, the weight of the piano is 970N

Explanation:

Power = work / time

Power = force × distance / time

P = (650 kg) (10 m/s²) (20 m) / (15 s)

P = 8667 W

Answer:

The answer is B.

Explanation:

Given that the current (Ampere) in a series circuit is same so we can ignore it. We can assume that the total voltage is 60V and all the 3 resistance are different, 20Ω, 40Ω and 60Ω. So first, we have to find the total resistance by adding :

Total resistance = 20Ω + 40Ω + 60Ω

= 120Ω

Next, we have to find out that 1Ω is equal to how many voltage by dividing :

120Ω = 60V

1Ω = 60V ÷ 120

1Ω = 0.5V

Lastly, we have to calculate the voltage at R1 so we have to multiply by 20 (R1) :

1Ω = 0.5V

20Ω = 0.5V × 20

20Ω = 10V

Explanation:

A theory is a way of explaining an object or event using a set of facts.

Answer:

[tex]E=6.01\times 10^{-3}\ J[/tex]

Explanation:

It is given that,

Side of a square loop, l = 24 cm = 0.24 m

Resistance of loop, R = 6.1 ohms

Initial magnetic field is 0.665 T and final magnetic field is 0 as the field is removed in 40 ms

We need to find the electrical energy dissipated in this process.

Due to change in magnetic field, the loop will induce a voltage. The induced voltage is given by :

[tex]V=-\dfrac{dB}{dt}\\\\V=\dfrac{BA}{t}[/tex]

If I is induced current then,

[tex]V=IR[/tex]

[tex]I=\dfrac{V}{R}\\\\I=\dfrac{BA}{tR}[/tex]

Power is given by voltage times current. So,

[tex]P=\dfrac{(BA)^2}{(t^2R)}[/tex]

Now, energy is given by the product of power and time. So,

[tex]E=\dfrac{(BA)^2}{(t^2R)}\times t\\\\E=\dfrac{(BA)^2}{(tR)}[/tex]

Now putting all the values in above formula. So,

[tex]E=\dfrac{(0.665\times (0.24)^2)^2}{(40\times 10^{-3}\times 6.1)}\\\\E=6.01\times 10^{-3}\ J[/tex]

So, the electrical energy of [tex]6.01\times 10^{-3}\ J[/tex] is dissipated in this process.

The electrical energy dissipated throughout this process will be "6.01 × 10⁻³ J".

According to the question,

Square loop's side, l = 24 cm or,

                                  = 0.24 m

Loop's resistance, R = 6.1 ohms

Initial magnetic field = 0.665 T

Final magnetic field = 0

We know the relation,

→ V = - [tex]\frac{dB}{dt}[/tex]

      = [tex]\frac{BA}{t}[/tex]

Also we know,

Current, V = IR

               I = [tex]\frac{V}{R}[/tex]

                 = [tex]\frac{BA}{tR}[/tex]

Now, Energy, E = [tex]\frac{(BA)^2}{t^2R}[/tex] × t or,

                          = [tex]\frac{(BA)^2}{tR}[/tex]

By substituting the values,

                          = [tex]\frac{(0.665\times (0.24)^2)^2}{40\times 10^{-3}\times 6.1}[/tex]

                          = 6.01 × 10⁻³ J

Thus the response above is correct.                                  

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Answer:

The magnitude and direction of the force per unit length of one wire on the other is 2 x 10⁻⁵ N/m, attractive force.

Explanation:

Given;

distance between the two parallel wires, r = 10 cm = 0.1 m

current in the first wire, I₁ = 2A

current in the second wire, I₂ = 5 A

The force per unit length on each wire can be calculated as;

[tex]\frac{F}{L} = \frac{\mu_oI_1I_2}{2\pi r}[/tex]

where;

μ₀ is permeability of free space = 4π x 10⁻⁷ m/A

[tex]\frac{F}{L} = \frac{\mu_oI_1I_2}{2\pi r} \\\\\frac{F}{L} = \frac{4\pi*10^{-7}*2*5}{2\pi *0.1} \\\\\frac{F}{L} = 2 *10^{-5} \ N[/tex]/ m

The direction of the force between the two wires is attractive since the current in the two wires are in opposite direction.

Therefore, the magnitude and direction of the force per unit length of one wire on the other is 2 x 10⁻⁵ N/m, attractive force.

Answer:

According to super hero logic , nothing will happen to him.

But according to science , yes he will get current shock but good news is that he wouldn't get elected until he is in contact with the wires.

He may / may not be affected but his suit will be damaged for sure as it is made of metal.

HOPE THIS HLEP AND PLSSSSS MARK AS BRAINLIEST AND THNXX :)

Answer:

(a) 1900 kg m²

(b) 8950 Nm

Explanation:

(a) The moment of inertia of a rod about its end is I = ⅓mL².

For 3 rods of mass m = 135 kg and length L = 3.75 m, the total moment of inertia is:

I = 3 (⅓ (135 kg) (3.75 m)²)

I = 1900 kg m²

(b) Net torque = moment of inertia × angular acceleration

∑τ = Iα

First, find the angular acceleration.

ω₀ = 0 rad/s

ω = 6.0 rev/s (2π rad/rev) = 37.7 rad/s

t = 8.0 s

α = (37.7 rad/s − 0 rad/s) / 8.0 rad/s = 4.71 rad/s²

∑τ = Iα

∑τ = (1900 kg m²) (4.71 rad/s²)

∑τ = 8950 kg m² / s²

∑τ = 8950 Nm

Answer:

1) a.  52.41 m/s

b. The skier will be going 15.35 m/s slower

2)  103.68 m

3) 35,127 J

4) a.  88.825 kJ

(b) 16.36 %

5) 3,071.12 J

Explanation:

1) a. The given height of the hill, h = 140.0 m

The mass of the skier at the top of the hill, m = 85.0 kg

The acceleration due to gravity, g = 9.81 m/s²

The initial potential energy, P.E of the skier = m×g×h = 85.0×140.0×9.81 = 116739 J

From the principle of conservation of energy, we have;

The potential energy, P.E. lost = The gain in kinetic energy, K.E.

m×g×h = 1/2×m×v²

116739 J = 1/2×85.0×v²

v² = 116739/(1/2*85.0)= 2746.8 m²/s²

v = √(2746.8 m²/s²) = 52.41 m/s

b. From 70 m up, we have;

The initial potential energy, P.E., of the skier is now = 85.0×70×9.81 = 58,369.5 J

The potential energy, P.E. lost = The gain in kinetic energy, K.E.

58,369.5 J = 1/2×85.0×v²

v² = 58,369.5/(1/2*85.0) = 1373.4 m²/s²

v = 37.06 m/s

The skier will be going 52.41 - 37.06 = 15.35 m/s slower

The skier will be going 15.35 m/s slower

2) From the principle of conservation of energy, the amount of work done (energy used) = The (potential) energy gained by the load

The amount of work done by the electric hoist = 356,000 J

The mass of the load = 350.0 kg

The height to which the load is raised = h

The potential energy gained by the load = m×g×h = 350.0×9.81×h

356,000 J = 350.0×9.81×h

h = 356,000/(350.0*9.81) = 103.68 m

The height to which the load is lifted= 103.68 m

3) The initial potential energy of the roller coaster cart = 600*35.0*9.81 = 206010 J

The final potential energy = 600*28.0*9.81= 164808 J

The velocity at point 3  = 4.5 m/s

The kinetic energy at point 3 = 1/2*600*4.5^2 = 6075 J

The total energy at point 3 = 164808 + 6075 = 170,883 J

The energy loss = The initial potential energy at point 1 - Total energy at point 3

The energy loss = 206010 - 170,883 = 35,127 J

The heat energy due to friction that must have been produced between points 1 and 3 = 35,127 J

4) a. The heat energy absorbed = mass × specific heat capacity for water, [tex]C_{water}[/tex] × Temperature change

The mass of the water = 2.5×10² g = 0.25 kg

[tex]C_{water}[/tex] = 4,180 J/(kg·°C)

Initial temperature = 10.0°C

Final temperature = 95°C

The temperature change = 95.0°C - 10.0°C = 85.0°C

The heat energy absorbed = 0.25*4,180* 85 = 88,825 J = 88.825 kJ

(b) The percentage efficiency = (Heat absorbed/(Heat supplied)) × 100

The heat supplied = 543 kJ

The efficiency = (88.825/543) × 100  = 16.36 %

5) The mass of the box = 115 kg

Force acting on the rope = 255 N

The angle of inclination of the force to the horizontal = 24.5°

The distance the box is displaced = 15.0 m to the right

The work done = Force applied × distance moved in the direction of the force

The work done = Force applied × distance moved in the direction of the force

Given that the load moves a distance 15.0 m to the right,we have;

The component of the force acting in the direction of the movement of the load (to the right) is 225 × cos(24.5°) =  204.74 N

The work done = 204.7*15 = 3071.12 J

The amount of work done  = 3,071.12 J

Answer:

625 cm²

Explanation:

The pressure is the same on both pistons.

F/A = F/A

200 N / 25 cm² = 5000 N / A

A = 625 cm²

Answer:

A = [m/s]

B = [m/s²]

Explanation:

Assuming that V has SI units of m/s, then A and BT must also have units of m/s.

A = [m/s]

BT = [m/s]

Since T has SI units of s:

B [s] = [m/s]

B = [m/s²]

Answer:

(a) Error: Other's ; Correction: Others'

(b) Error: to ; Correction: for

(c) Error: with ; Correction: of

(d) Error: prepares ; Correction: prepare

Explanation:

a)  The error is in the word "other's" as the position of apostrophe is wrong, so the correct word will be "others'", it shows plural nouns.

b)  The error is in the word "to", so the correct word will be "for" as for is use to talk about a purpose.

c)  The error is in the word "with"  and the correct word will be "of" as of indicates relationships between other words including things that made of other things.

d)  The error is in the word "preapres" and the correct word will be "prepare".

Answer:

yeah this statement is tru

Explanation:

it is because the speed of the bullet is more than the speed of rolling ball .so from this reason we cannot catch a bullet.

A bullet will be moving much faster than a rolling ball. Even seeing a bullet in flight requires it to be extremely low velocity.

Answer:

900 cm/s or 9 m/s.

Explanation:

Data obtained from the question include the following:

Length (L) = 30 cm

frequency (f) = 60 Hz

Velocity (v) =.?

Next, we shall determine the wavelength (λ).

This is illustrated below:

Since the wave have 4 node, the wavelength of the wave will be:

λ = 2L/4

Length (L) = 30 cm

wavelength (λ) =.?

λ = 2L/4

λ = 2×30/4

λ = 60/4

λ = 15 cm

Therefore, the wavelength (λ) is 15 cm

Now, we can obtain the speed of the wave as follow:

wavelength (λ) = 15 cm

frequency (f) = 60 Hz

Velocity (v) =.?

v = λf

v = 15 × 60

v = 900 cm/s

Thus, converting 900 cm/s to m/s

We have:

100 cm/s = 1 m/s

900 cm/s = 900/100 = 9 m/s

Therefore, the speed of the wave is 900 cm/s or 9 m/s.

Answer:

1: the refracted angle in the first face is equal to the incident angle that is 60degrees

2. Emergence Angle is 42degrees

Explanation:

Pls see attached file

Answer:

B. they have less mass than their reactants

Explanation:

In both nuclear fission and nuclear fusion, the products have less mass than their reactants. So, option B is correct.

Nuclear reaction is defined as the reaction that involves the collision between one or more atomic nuclei and a highly energetic subatomic particle to produce one or more nuclei along with the emission of a large amount of energy.

Here,

Nuclear fission and fusion are two types of nuclear reactions that involves the production of large amount of energy from atomic nuclei.

Nuclear fission is the nuclear reaction in which a heavier nucleus is split into two or more lighter nuclei, under radioactive condition, with the release of a massive amount of energy.

Nuclear fusion is the nuclear reaction in which two or more lighter nuclei nuclei fuse together under radioactive condition and forms a heavier nuclei and by releasing a large amount of energy.

In both nuclear fission and nuclear fusion, there occurs a release of large amount of energy. This is because most of the mass of the reactants is converted into energy which is known as the mass-energy. So the products of these nuclear reactions will have lesser mass than their reactants.

Hence,

In both nuclear fission and nuclear fusion, the products have less mass than their reactants.

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Answer:

59%

Explanation:

Data obtained from the question include the following:

Input temperature = 495 K

Output temperature = 293 K

Efficiency =?

The efficiency of the car engine can be obtained by multiplying the ratio of the output temperature to the input temperature by 100 as shown below:

Efficiency = output /input x 100

Efficiency = 293/495 x 100

Efficiency = 59.1 ≈ 59%

Therefore, the efficiency of the car engine is approximately 59%