A man of mass 75kg stands on a weighing machine in a lift. Determine the reading of the weighing machine when the lift is moving: 1. Upwards with an acceleration of 2m/s² 2. Downwards with a constant velocity of 1.5m/s 3. Downwards with an acceleration of 2.5m/s²

Answer:

The input power is [tex]44.4\times10^{3}\ kW[/tex]

Explanation:

Given that,

Time = 15 min

Volume of water = 30 m³

Height = 40 m

Efficiency = 30%

Density of water = 1000 kg/m³

Suppose, acceleration due to gravity = 10 m/s²

We need to calculate the mass of water pumped

Using formula of mass

[tex]Mass = Volume\times density[/tex]

Put the value into the formula

[tex]Mass=30\times1000[/tex]

[tex]Mass=3\times10^{4}\ kg[/tex]

We need to calculate the output power

Using formula of power

[tex]P_{out}=\dfrac{W}{t}[/tex]

[tex]P_{out}=\dfrac{mgh}{t}[/tex]

Put the value into the formula

[tex]P_{out}=\dfrac{3\times10^{4}\times10\times40}{15\times60}[/tex]

[tex]P_{out}=\dfrac{4}{3}\times10^{4}\ Watt[/tex]

We need to calculate the input power

Using formula of efficiency

[tex]\eta=\dfrac{P_{out}}{P_{in}}[/tex]

[tex]P_{in}=\dfrac{P_{out}}{\eta}[/tex]

Put the value into the formula

[tex]P_{in}=\dfrac{4\times100\times10^{4}}{3\times30}[/tex]

[tex]P_{in}=\dfrac{4\times10^{5}}{9}\ Watt[/tex]

[tex]P_{in}=44.4\times10^{3}\ kW[/tex]

Hence, The input power is [tex]44.4\times10^{3}\ kW[/tex]

Answer:

80 cm.

Explanation:

Since the metre rule is 1 m i.e 100 cm it means that the mass of the metre can be obtained at the 50 cm mark.

But the metre is pivoted at the 60 cm.

Please refer to the attached photo for details.

In the attached photo, y is the distance between the mark (that will balance the metre rule when a 50 g mass is hunged) and the pivot.

Thus, we can obtain the value of y as follow:

Anticlock wise moment = Clock wise moment

Anticlock wise moment = 100 × 10

Clock wise moment = y × 50

Anticlock wise moment = Clock wise moment

100 × 10 = y × 50

Divide both side by 50

y = (100 × 10) /50

y = 20 cm

Now, to obtain the mark, B that will balance the metre, we simply add 20 cm to 60 cm ie

B = 60 + 20

B = 80 cm

Answer:

С. a single component that can't be separated

Explanation:

Substance : It is the pure form of matter or we can say that it is a matter that contains only one type of molecule of atom. It can not be separated by physical process.

For example : Water is a substance.

Mixture : It is a combination of different type of atoms or molecules and it is an impure form.

For example : Sodium chloride with water is a mixture.

Hence, the correct option is, (C) a single component that can’t be separated.

A substance is a single component that can't be separated by the physical process therefore the correct answer is option C.

A chemical compound is a mixture of two or more chemical components, whether they are related or unrelated.

For instance, the molecular H2O is composed of one hydrogen atom and two oxygen atoms.

For instance, water is a material that cannot be physically divided yet may be separated using electrolysis.

Mixture: This impure form is made up of several different kinds of atoms or molecules.

A mixture is, for instance, sodium chloride and water.

As a result, (C), a single, irreducible component, is the right answer.

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Answer:

The difference between One-way as well as reversible rotary motion​ is described below.

Explanation:

Answer:

Explanation:

Initially the packet was ascending up with the balloon.

Taking upward as positive direction;

initial velocity, u = 4.9 m/s

final velocity = v m/s

initial height, h₁ = 100 m  

final height, h₂ = 0

a = -9.8 m/s²

time taken = t seconds

Considering the second equation of motion.

S = ut + 1/2at^2

s = ut + 0.5at²

(h₂-h₁) = ut + 0.5at²

0- 100 = 4.9t + 0.5×(-9.8)×t²

-100 = 4.9t - 4.9t²

4.9t² -4.9t -  100 =0

t² -t - 20.41 = 0

Using : b±√(b²-4ac))/(2a)....  1

Where a =1, b = -1 c =-20.408

Substituting the values into equation 1

Solving it, we get  t = 5.045s

v = u + at = 4.9 -9.8×5.045 = 4.9 - 49.44 = -44.54 m/s

The final velocity is -44.54 m/s, and it took  5.045s to reach the ground.

Answer:

luminous bcz they emits light by their own and don't need other resources to emit light

Answer:

O- to track how fast a heart beats

Explanation:

Answer:

Diameter of Wire = 4.5 mm

Explanation:

First, we need to find the fractional part of the reading. The fractional part o the reading can be given by the following formula:

Fractional Part = Circular Scale Reading x Least Count

where,

Circular Scale Reading = 50

Least Count = 0.01 mm

Therefore,

Fractional Part = (50)(0.01 mm)

Fractional Part = 0.5 mm

Now, the diameter of the wire can be given by using the following formula:

Diameter of Wire = Linear Scale Reading + Fractional Part

Diameter of Wire = 4 mm + 0.5 mm

Diameter of Wire = 4.5 mm

Answer:

F = 0.408 N

Explanation:

It is given that,

Weight of a wooden block, W = 8 N

Weight, W = mg

m is mass of wooden block

[tex]m=\dfrac{W}{g}\\\\m=\dfrac{8\ N}{9.8\ m/s^2}\\\\m=0.816\ kg[/tex]

Acceleration of the block, a = 0.5 m/s²

Force, F = ma

[tex]F=0.816\ kg\times 0.5\ m/s^2\\\\F=0.408\ N[/tex]

So, the magnitude of force applied to the wooden block is 0.408 N.

Answer:

Explanation:

The velocity ratio of  a wheel and axle is the ratio of the radius (R) of the wheel to the radius (r) of the axle. It is expressed as;

VR = R/r

Since radius = diameter/2

VR = (D/2)/(d/2)

VR = D/d

D is the diameter of the wheel and 'd' is the diameter of the axle.

Given VR = 3 and d = 5cm

3 = D/5

D = 15 cm

If the diameter of the wheel is 15cm, the radius of the wheel will be 15/2 = 7.5cm.

b) Workdone by the load = Load * distance moved by load

Given load = 60kg

Distance moved by load = 2π*radius of axle

Distance moved by load  = 2π(0.025) = 0.157

workdone by load = 60* 0.157 = 9.42J

Effort = Workdone by load/distance moved by the wheel

Effort = 9.42/2π(0.075)

Effort = 9.42/0.471

Effort = 20kg

Hence the effort applied is 20kg

c) MA = Load/Effort

MA = 60/20

MA = 3

d) Efficiency = MA/VR * 100%

Efficiency = 3/3 * 100%

Efficiency = 100%

Answer:

V is greater

Explanation:

because v intial at that time V final is the that speed which it is going at that time

Answer:

[tex] \boxed{ \bold{ \boxed{ \sf{39.2 \: m/ {s} \: }}}}[/tex]

Explanation:

Given,

Distance travelled ( d ) = 176.4 meters

Time taken ( t ) = 4.5 seconds

Finding the speed of a cheetah

Speed [tex] \sf{ = \frac{distance \: travelled}{time \: taken} }[/tex]

[tex] \sf{ = \frac{176.4}{4.5} }[/tex]

[tex] \sf{ = 39.2 \: m/ {s} \: }[/tex]

------------------------------------------------------------------------

Let's learn about Speed :

Suppose a body moves 20 m in 2 seconds, either on a curved path or on a straight path. So , 10 m is the distance travelled by the body in each second which can be written as 10 m/s. This is called speed of the body. Thus, Speed is defined as the distance travelled per unit time. It is the rate of distance travelled by a body.

Mathematically,

[tex] \boxed{ \bold{ \sf{speed = \frac{distance \: travelled}{time \: taken} }}}[/tex]

In SI system, the unit of distance is metre and time is second. Thus , the SI unit is speed is m/s.

Hope I helped!

Best regards!!

Answer:

The correct answer is A

Explanation:

Hope this helps....

Have a nice day!!!!

The statement that correctly describes the quantitative relationship between acceleration and the net force on an object shown in the data table is as follows:

Thus, the correct option for this question is D.

Acceleration may be defined as a type of rate at which the velocity of an object may change with respect to time. This change in velocity may come in terms of both speed and direction. Acceleration is a type of vector quantity because it has both magnitude and direction.

According to the context of this question, when the net force applied to an object may change, the acceleration may also change. This change is significantly induced by the same factor. This is because the acceleration of an object may directly rely on the net force applied.

Therefore, when the net force applied to an object changes, the acceleration changes by the same factor. Thus, the correct option for this question is D.

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[tex] \large{ \underline{ \underline{ \bf{ \purple{Given}}}}}[/tex]

[tex] \large{ \underline{ \underline{ \bf{ \green{To \: find}}}}}[/tex]

[tex] \large{ \underline{ \underline{ \red{ \bf{Now, \: What \: to \: do?}}}}}[/tex]

We can solve the above question using the three equations of motion which are:-

So, Here a is acceleration of the body, u is the initial velocity, v is the final velocity, t is the time taken and s is the displacement of the body.

[tex] \large{ \bf{ \underline{ \underline{ \orange{Solution:}}}}}[/tex]

We are provided with,

By using 1st equation of motion,

⇛ v = u + at

⇛ v = 250 + (-3)45

⇛ v = 250 - 135 m/s

⇛ v = 115 m/s

✤ Final velocity of mobile = 115 m/s

━━━━━━━━━━━━━━━━━━━━

Answer:

It will fall at the same speed in both locations

Explanation:

When an object is falling, it is accelerated to the same degree irrespective of the height from which it is falling.

All objects on the earth's surface experience an acceleration due to gravity. This acceleration due to gravity is the same for all objects irrespective of their height or mass.

Hence for a stone dropped from the same height as Terai and the top of a mountain, the acceleration due to gravity is the same in both cases hence they will fall at the same speed.

Answer:

B.

Explanation:

as there is a '-' sign before the magnification value, it forms a real image.

so the last two options get cancelled.

as the value of magnification is 0.87 ie. lesser than 1, we can say that the image is smaller.

The type of image is formed by a lens if m = -0.87 would be smaller than the object and the object is real

A lens is a transmissive optical tool that employs refraction to focus or disperse a light beam. The power of the lens is expressed in the dioptre which is the reciprocal of the focal length of the lens.

The image formation through the lens is calculated with the help of the lens formula given as follows

1/f = 1/v - 1/u

where f is the focal length of the lens

u is the distance of the object from the lens

v is the distance of the image formed from the

magnification (m) = size of image /size of the object

As given in the problem image is formed by a lens if m = -0.87

Thus, the negative sign represents that the image formed by the object is real, and the magnitude of the magnification is less than 1 this represents that size of the image is smaller than the size of the object.

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Explanation:

(i) The horizontal component of the tension in the right wire points right, and the horizontal component of the tension in the left wire points left.  Since these components are equal and opposite, the resultant horizontal force is 0.

∑Fₓ = 15 N cos 20° − 15 N cos 20°

∑Fₓ = 0 N

(ii) ∑Fᵧ = 15 N sin 20° + 15 N sin 20°

∑Fᵧ = 10.26 N

i) The resultant horizontal component of the tension forces is 0N

ii) The resultant vertical component of the tension forces is 10.26N

iii) The sum of force along the horizontal is zero because the force has the same magnitude and moving in the opposite direction.

i) From the given figure, the horizontal component of the force is given as;

[tex]F_x = + 15 cos 20^0 + (-15cos20^0)\\F_x = + 15 cos 20^0 -15cos20^0\\F_x =0[/tex]

The sum of force along the horizontal is zero because the force has the same magnitude and moving in the opposite direction.

ii) The vertical component of the force is expressed as

[tex]F_y = + 15 sin 20^0 + 15sin20^0)\\F_y = 2(15sin20^0)\\F_y=2(5.13)\\F_y=10.26N[/tex]

Hence the resultant vertical component of the tension forces is 10.26N

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Answer:

a. [tex]2.54 \times 10^{21} NC^{-1}[/tex]

b. Outwards

Explanation:

The computation is shown below:

a. The magnitude could be computed by applying the following formula

Electric field, E is

[tex]= \frac{kq}{r^{2}} \\\\ = \frac{9\times10^{9} \times86\times1.6\times10^{-19}}{(6.98\times10^{-15})^2}[/tex]

[tex]= 2.54 \times 10^{21} NC^{-1}[/tex]

b. As we can see that there is a positive charge so the direction would be in the outward direction in the electric field i.e. produced by the protons

Basically we applied the above formula for the first part

Answer:

The distance the car travels is 115500 m in S.I units

Explanation:

Distance d = vt where v = speed of the car and t = time taken to travel

Now v = 99 km/h. We now convert it to S.I units. So

v = 99 km/h = 99 × 1000 m/(1 × 3600 s)

v = 99000 m/3600 s

v = 27.5 m/s

The speed of the car is 27.5 m/s in S.I units

We now convert the time t = 70 minutes to seconds by multiplying it by 60.

So, t = 70 min = 70 × 60 s = 4200 s

The time taken to travel is 4200 s in S.I units

Now the distance, d = vt

d = 27.5 m/s × 4200 s

d = 115500 m

So, the distance the car travels is 115500 m in S.I units

Answer:

Which best describes what happens if two waves meet and build on each other?

destructive interference

reflection

absorption

Explanation:

When two waves meet in phase they will overlap together and form a constructive interference. The resultant amplitude of the waves will be greater than that of individual waves.

A wave of greater, lower, or the same amplitude is created when two waves merge through interference by combining their displacements at all points in space and time.

The interaction of waves that are coherent or correlated with one another, either because they originate from the same source or because their frequencies are similar or almost identical, leads to both constructive and destructive interference.

All sorts of waves, including light, radio, acoustic, surface water waves, gravity waves, and matter waves, can exhibit interference effects. In constructive interference, the waves are in single phase forms a resultant wave with higher amplitude.

When waves from out of phase meets, the resultant wave will have an amplitude less than the individual amplitudes. Here, the waves are meet in phase and build on each is constructive interference.

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Answer: 9.675 Hz .

Explanation:

Given, velocity of waves = 12.9 m/s

Length of string = 2.00 m

Let [tex]\lambda[/tex] be the wavelength , then for 3 loops

[tex]\dfrac{3}{2}\lambda= \text{length of string}\\\\\Rightarrow\ \dfrac{3}{2}\lambda= 2\ m\\\\\Rightarrow\ \lambda= \dfrac{4}{3}\ m[/tex]

Now , velocity = frequency x wavelength

Then, frequency = [tex]\dfrac{velocity}{wavelength}[/tex]

[tex]=\dfrac{12.9\times3}{4}\\\\=9.675\ Hz[/tex]

hence, it will create standing waves with 3 loops at 9.675 Hz .

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:

The factor that determines the mechanical advantage (or ideal mechanical advantage (IMA) - in the absence of frictional forces) in a simple machine is the ratio perpendicular distance of the applied force to the fulcrum to the perpendicular distance of the load to the fulcrum

The mechanical advantage can therefore by larger than 1 (requiring less force per load), or equal to 1 (effort equal to load) or less than 1( effort more than load)

Explanation:

Answer:

0.54mm

Explanation:

Given the following :

Wavelength (λ) of Soundwave in air = 0.12mm

Velocity of sound wave (v) = 340m/s

Calculate the frequency (f) :

v = fλ

Wavelength to metres

1000mm = 1 m

0.12mm = (0.12/1000)m

= 0.00012m

v = fλ

340 = F * 0.00012

f = 340 / 0.00012

f = 2833333.3 Hz

Wavelength of Soundwave in the patient:

Velocity of sound wave through body tissue = 1540m/s

Therefore,

Using v = fλ

λ = v / f

λ = 1540 / 2833333.3

λ = 0.0005435m

λ = (0.0005435 * 1000)mm

λ = 0.5435mm = 0.54mm

The distance between neighbouring, identical wave components, such as adjacent compressions, determines a sound's wavelength. The number of waves passing a spot in a given amount of time is known as the frequency, which is the same as the source's frequency.

Wavelength (λ) of Soundwave in air = 0.12 mm

Velocity of sound wave (v) = 340m/s

Calculate the frequency (f) :

v = fλ

Wavelength to metres

1000 mm = 1 m

0.12 mm = (0.12/1000)m

= 0.00012 m

v = fλ

340 = F × 0.00012

f = 340 / 0.00012

f = 2833333.3 Hz

Wavelength of Soundwave in the patient:

Sound waves travel through body tissue at a speed of 1540 m/s.

Therefore, Using v = fλ

λ = v / f

λ = 1540 / 2833333.3

λ = 0.0005435m

λ = (0.0005435 × 1000)mm

λ = 0.5435mm = 0.54 mm

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Answer:

Explanation:

Evolution/Advancement on the off chance that you see,then you will find this is a definitive revelation of science.It demonstrated that how people came into the world.How different creatures endure and from where they have hit on where they are today.All such things are the piece of development process.

New things advanced consistently from the past one and its a slow process.For anything to sprout you need a seed.As per the scientist,evolution is a reality and it is a steady procedure and it is happening.There are scarcely any situations where in the old harvest can yield new assortment as well.This is something many refer to as advancement only.Its a ceaseless process.Whatever comes,it accompanies certain misstep or zones of improvement,so if there happens to be a few changes would prompt improvement of new thing.

In the event that you see at an early stage,worms were available ,from where the fish came,then some went ahead land and began adjusting the progressions require to make due on land,started strolling on legs,developed lungs,then likewise there were advancement of the considerable number of things require to proceed with the life.All are the piece of development as it were.

hence,Darwin said,that natural selection can prompt evolution.This is likewise evident that so as to address the issue of food and nutrition,everybody works and as long as you get those needs,there will be development in all aspects.Similarly happened to the antiquated occasions when advancement occurred.

Hence,The development is truth and is a continuous procedure according to the science.When you go to demonstrate some case,there are consistently a point from where new methodology can be shaped and can prompt another disclosure.

If we consider the theory of evolution then we can say that it’s a proven theory, the reason people says that scientists don’t prove anything is because of the fact that they always implement “Precautionary principle” in their research finding.

Answer:

.

Explanation:

Answer:

They are:

1) change position

2) distract yourself

3) Get fresh air

4) Face the direction you are going.

5) Drink water.

6) Play music.

7) Put your eyes on horizon.  

Explanation:

Hope it helps.

Answer:

a=F/m

a=12N/3kg  (here newton can be written as kgm/s^2 so kg will be cancelled)

a=4m/s^2

Explanation:

Explanation:

Average speed = distance / time

v_avg = 47 km / 1.72 hr

v_avg = 27.3 km/hr

Answer:

The answer is below

Explanation:

The efficiency of a machine is the ratio of its output to its input. The efficiency shows how effective the machine by the way it converts the input energy into work. The higher the efficiency of the machine the more effective it is. The efficiency is usually less than 1.

Given that the machine uses diesel oil (input) that can produce 3.0 x 10⁹ J of energy while the work performed by the machine (output) is 2.7 x 10⁸ J. The efficiency is given as:

Efficiency = output / input = 2.7 x 10⁸ J / 3.0 x 10⁹ J = 0.09 = 9%

This means that the machine is not effective because of its low efficiency