It is easier to lift the same load by using three pulley system than by using two-pulley system. why give reason.​

Answer:

a. 0.8 cm

Explanation:

The distance of the object from the lens, u = 1 cm

The magnification of the lens, m = 5

The focus of a lens formula is given as follows;

[tex]f = \dfrac{1}{\dfrac{1}{v} + \dfrac{1}{v} }[/tex]

The magnification of the lens, m = -v/u

Where;

v = The distance of the image from the lens

Therefore, we have;

v = m × u

∴ v = 5 × 1 cm = 5 cm (on the other side of the lens)

From which we get;

[tex]f = \dfrac{1}{\dfrac{1}{1} + \dfrac{1}{5} } = \dfrac{5}{6} \approx 0.8[/tex]

The focal length ≈ 0.8 cm

Answer:

The moment of inertia should be decreased.

Explanation:

The torque is given by

Torque = Moment of inertia x angular velocity

To keep the torque constant, the spin rate be increased when the moment of inertia decreases.  

The moment of inertia of the body are the efforts to put the object in rotation.  

Answer:

Explanation:

Assuming the squirrel is jumping off the ground, here's what we know but don't really know...

v₀ = 4.0 at 50.0°

So that's not really the velocity we are looking for. We are dealing with a max height problem, which is a y-dimension thing. Therefore, we need the squirrel's upward velocity, which is NOT 4.0 m/s. We find it in the following way:

[tex]v_{0y}=4.0sin(50.0)[/tex] which gives us that the upward velocity is

v₀ = 3.1 m/s

Moving on here's what we also know:

a = -9.8 m/s/s and

v = 0

Remember that at the very top of the parabolic path, the final velocity is 0. In order to find the max height of the squirrel, we need to know how long it took him to get there. We are using 2 of our 3 one-dimensional equations in this problem. To find time:

v = v₀ + at and filling in:

0 = 3.1 - 9.8t and

-3.1 = -9.8t so

t = .32 seconds.

Now that we know how long it took him to get to the max height, we use that in our next one-dimensional equation:

Δx = [tex]v_0t+\frac{1}{2}at^2[/tex] and filling in:

Δx = [tex]3.1(.32)+\frac{1}{2}(-9.8)(.32)^2[/tex] and using the rules for adding and subtracting sig fig's correctly, we can begin to simplify this:

Δx = .99 - .50 so

Δx = .49 meters

Answer:

[tex]V.E=498.02m/s^2[/tex]

Explanation:

From the question we are told that:

Radius [tex]r=301Km[/tex]

Gravitational acceleration [tex]g=0.412 m/s^2[/tex]

Generally the equation for Escape velocity is mathematically given by

 [tex]V.E^2=2gr[/tex]

 [tex]V.E^2=2*0.412m/s^2*301000[/tex]

 [tex]V.E^2=248024[/tex]

 [tex]V.E=\sqrt{248024}[/tex]

 [tex]V.E=498.02m/s^2[/tex]

Answer:

a. Tiempo = 25000 segundos

b. Distancia = 19200 metros

Explanation:

Dados los siguientes datos;

Velocidad = 8 m/s

Distancia = 200 km a metros = 200 * 1000 = 200,000

Para encontrar el tiempo para cubrir la distancia anterior;

Tiempo = distancia/velocidad

Tiempo = 200000/8

Tiempo = 25000 segundos

b. Para encontrar la distancia recorrida en 40 minutos;

Tiempo = 40 minutos a segundos = 40 * 60 = 2400 segundos

Distancia = velocidad * tiempo

Distancia = 8 * 2400

Distancia = 19200 metros

Answer:

Large spherical regions from which no light is detected

Explanation:

A black hole is an object that has an extremely high density such that it possesses very powerful gravitational force that prevents the escape of all objects including light from it, and consumes nearby objects.

Due to the power of the gravitational force of a black hole, at the center, objects are infinitesimally compressed resulting in the inapplicability of the concept of space and time and the location is known as a singularity

Therefore, the search for black holes involves searching for large spherical regions from which no light is detected.

Answer:

Explanation:

1)Melting:

Melting is the process by which a substance changes from the solid phase to the liquid phase. ... Melting occurs when the internal energy of a solid increases, usually through the application of heat or pressure, such that the molecules become less ordered.

2) liquefication:

In physics and chemistry, the phase transitions from solid and gas to liquid (melting and condensation, respectively) may be referred to as liquefaction. The melting point (sometimes called liquefaction point) is the temperature and pressure at which a solid becomes a liquid.

3) vaporization:

Vaporization, conversion of a substance from the liquid or solid phase into the gaseous (vapour) phase. If conditions allow the formation of vapour bubbles within a liquid, the vaporization process is called boiling. Direct conversion from solid to vapour is called sublimation.

4) Sublimation occurs as molecules of a substance in the solid state go to the vapor state directly, rather than through the liquid state. ... ⭕In terms of the kinetic molecular theory, we know that molecules are in constant random motion, even when the substance is below the melting point.

Answer:

[tex]d=58m[/tex]

Explanation:

From the question we are told that:

Initial Speed [tex]U=12m/s[/tex]

Time [tex]T=5.6s[/tex]

Angle [tex]\theta=30[/tex]

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

[tex]d=d'+ut+\frac{at^2}{2}[/tex]

[tex]d=12cos30*5.6[/tex]

[tex]d=58m[/tex]

Answer:

below

Explanation:

that is the procedure above

Answer:

The number of electrons flowing per second is [tex]4.375\times 10^{18}[/tex].

Explanation:

How many electrons per second pass through a section of wire that carries a current of 0.70 A.?

Current, I = 0.7 A

time, t = 1 s

According to the definition of current, let the charge is q.

q = I t

q = 0.7 x 1 = 0.7 C

Let the number of electrons is n.

[tex]n =\frac{q}{e}\\\\n = \frac{0.7}{1.6\times 10^{-19}}\\\\n = 4.375\times 10^{18}[/tex]

Answer:

This question is incomplete but the completed question is below

As a girl pushes an object across a wood floor, she suddenly comes to an area where the floor has been waxed recently, making it slippery. What becomes true of the coefficient of kinetic friction? A. The coefficient of kinetic friction increases. B. The coefficient of kinetic friction decreases. C. The coefficient of kinetic friction becomes zero. D. The coefficient of kinetic friction becomes negative.

The correct option is B

Explanation:

Coefficient of kinetic friction can be defined as the frictional force resisted by the motion of an object. From the question, it might take the girl to apply a force equivalent to just half that of the weight of the object to overcome friction to keep the object moving on a wood floor. Once she gets to the waxed area, the frictional force reduces, thereby also reducing the coefficient of kinetic friction further. Thus, she will be able to use less than half of the force (equivalent to less than half of the weight of the object) to push the object.

Thus, the correct option is B.

Answer:

it takes 365 days to revolve around the star(sun)

Answer:

the answer is 4 acceleration is 0

Explanation:

this is because when parallel line is drawn through x axis the velocity will bw uniform

plz brainliest

The amount of energy required for a unit mass of a substance to undergo a phase change from liquid to gas.

Answer:

The linear speed of the car, v, is 24.26 m/s

Explanation:

Given;

radius of the car's tire, r = 0.330 m

angular speed of the car, ω = 11.7 revolutions/s

The angular speed of the car in radian per second:

[tex]\omega = 11.7 \ \frac{rev}{s} \times \frac{2\pi \ rad}{1 \ rev} \\\\\omega = 73.523 \ rad/s[/tex]

The linear speed of the car, v, is calculated as;

v = ωr

v = 73.523 rad/s  x  0.33 m

v = 24.26 m/s

Therefore, the linear speed of the car, v, is 24.26 m/s

Answer:

The angle is 16 degree.

Explanation:

A uniformly charged infinite plane, density σ = 4.10-9 C/cm2, is placed vertically in air. A small ball of mass 8 g, with charge q = 10-8 C, hangs close to the plane, so that the string is initially parallel to the plane. Take g = 9.8m/s2 . In equilibrium, by what angle does the string hanging from the ball make an angle with the plane?

Surface charge density,   σ = 4 x 10^-9 C/m^2

charge, q = 10^-8 C

mass, m = 0.008 kg

Let the tension is the string is T and the angle is A.

[tex]T sin A = q E....(1)\\\\T cos A = m g .... (2)\\\\Divie (1) by (2)\\\\tan A =\frac{q E}{m g}\\\\tan A = \frac{10^{-8}\times 4\times 10^{-5}}{2\times 8.85\times 10^{-12}\times 0.008\times9.8}\\\\tan A = 0.288\\\\A = 16 degree[/tex]

Answer:

second lag

Explanation:

If in a cup game, a specified time limit is assigned to both teams to score high. If both teams are unable to score or if score of both the teams is equal then there is another second lag played where each team tries to score high. Even if in second lag both teams fail to score higher than other the last third lag is played or else game is declared draw.

The Torque is only produced when the force is applied perpendicular to the moment arm.

The equal and opposite force acting at a point from the axis of rotation is called the moment.

M = F x r

Moment of force is also called as Torque.

Moment arm is the distance of the point of application of force from the axis of rotation of the body.

Thus, the perpendicular component only, produces the torque.

Learn more about moment of force.

https://brainly.com/question/6278006

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Answer:

Time = 16.667 seconds

Explanation:

Given the following data;

Distance = 50 meters

Velocity = 3 m/s

To find the time it will take;

Velocity can be defined as the rate of change in displacement (distance) with time. Velocity is a vector quantity and as such it has both magnitude and direction.

Mathematically, velocity is given by the equation;

Velocity = distance/time

Making time the subject of formula, we have;

Time = distance/velocity

Time = 50/3

Time = 16.667 seconds

Answer:

C. More of the heat is transferred to the kinetic energy of the copper atoms than to the kinetic energy of the water molecules.

Explanation:

Both equal masses of water and copper were heated at the same temperature. Since copper is a good conductor of heat compared to water, its  absorbs more heat. Which in-turn increases the rate of vibrations of the atoms in the copper mass, thus increasing their kinetic energy.

In the case of water, its molecules displaces one another after being heated to a higher temperature compared to neighboring molecules. So that the heated molecule becomes less dense and floats to the surface of water.

This property of copper makes it to be heated to a higher final temperature than the water.

Answer:

[tex]v=-4.93\times 10^{5}~m/s[/tex] [negative sign denotes that it is moving away]

Explanation:

Actual wavelength of hydrogen spectral lines, [tex]\lambda=121.6~nm[/tex]

Apparent wavelength of hydrogen spectral lines from a star, [tex]\lambda'=121.8~nm[/tex]

So, shift in wavelength:

[tex]\Delta \lambda=\lambda'-\lambda[/tex]

[tex]\Delta \lambda=121.8-121.6[/tex]

[tex]\Delta \lambda=0.2~nm[/tex]

Using Doppler's shift:

[tex]\frac{\Delta \lambda}{\lambda} =-\frac{v}{c}[/tex]

[tex]\frac{0.2}{121.6} =-\frac{v}{3\times 10^8}[/tex]

[tex]v=-4.93\times 10^{5}~m/s[/tex] [negative sign denotes that it is moving away]

Answer:

(a) The motion is uniform

(b)  11.11 m/s

Explanation:

(a)

From the table below, the motion of the bus is uniform.

(b)

Speed(s) = Δd/Δt

s = Δd/Δt............. Equation 1

From the table,

Given: Δd = 10 km = 10000 m, Δt = 15 minutes = (15×60) = 900 seconds

Substitute these values into equation 1

s = 10000/900

s = 11.11 m/s

Answer:

The gravitational potential energy (gpe) possessed by an object or body is directly proportional to the height of the object or body.

Explanation:

Gravitational potential energy (GPE) is an energy possessed by an object or body due to its position above the earth.

Mathematically, gravitational potential energy is given by the formula;

G.P.E = mgh

Where;

G.P.E represents potential energy measured in Joules.

m represents the mass of an object.

g represents acceleration due to gravity measured in meters per seconds square.

h represents the height measured in meters.

Generally, the gravitational potential energy (gpe) of an object or body is directly proportional to the height of the object or body. Thus, the gravitational potential energy of a body increases as the height of the body increases.

In conclusion, an object with a higher height would have a higher gravitational potential energy.

Answer:

b)3:2

Explanation:

The dispersive power is the reciprocal of the focal length:

[tex]P=\frac{1}{f}[/tex]

Given the ratio of focal lengths:

[tex]\frac{f_1}{f_2} = \frac{2}{3}\\\\\frac{\frac{1}{P_1}}{\frac{1}{P_2}}=\frac{2}{3}\\\\\frac{P_2}{P_1}=\frac{2}{3}\\\\\frac{P_1}{P_2}=\frac{3}{2}[/tex]

Therefore,

P₁ : P₂ = 3 : 2

Hence, the correct option is:

b)3:2

Answer:

40 kW

Explanation:

A railcar has a continuous 1000 N decelerating force any time it is in motion. If no braking occurs, how much power would be required to keep the railcar moving at 40 m/s

Solution:

Power in Physics is the rate of doing work and the work can be mechanical, electrical, etc. The S.I unit of power is the watts (W).

The power required to keep the car moving must match the work done by the friction force (decelerating force) that tends to slow down the railcar.

Work done = Force * displacement

Power = Work done / time = (Force * displacement) / time

Power = Force * (displacement / time)

Power = force * velocity = 1000 N * 40 m/s = 40000 W

Power = 40 kW

Answer:

2.38m

Explanation:

Use potential energy

PE= mgh

42= 1.8*9.8*h

solve for h

to get h= 2.38 m

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Answer:

MOMENTUM = 40kg ms-¹

hope it helps

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