Give reason.


b} String roller is an example of wheel and axel .Why?

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Answer:

TEJ as this is a thing you wont get

The final temperature of the mixture is 43.62 °C, If 200 ml of tea at 90 °C is poured into a 400 g glass cup initially at 25 °C.

To solve the question above, we apply the law of calorimetry

The law of calorimetry: which states that if there is no lost of heat the surrounding, heat lost is equal to heat gained, or it can be stated as heat absorbed by a cold body is equal to heat released by a hot body, provided there is no lost of heat to the surrounding.

The law above is expressed mathematically as

[tex]Cm(T-t) = C'm'(t-T')[/tex]............. Equation 1

Using equation 1 to solve the question,

[tex]0.4(840)(90-t) = 0.2(4186)(t-25)[/tex]

[tex]336(90-t) = 837.2(t-25)[/tex]

[tex]30240-336t = 837.2t-20930[/tex]

collect like terms

[tex]837.2t + 336t = 30240+20930[/tex]

[tex]1173.2t = 51170[/tex]

[tex]t = 51170/1173.2[/tex]

[tex]t = 43.62[/tex] °C

Hence, the final temperature of the mixture is 43.62 °C

Learn more about calorimeter here: https://brainly.com/question/15479803

Answer:

The final temperature of the system is 41.657 °C.

Explanation:

Let consider the tea-cup system as an isolated system, that is, a system with no energy and mass interactions with the surroundings. From the perspective of the First Law of Thermodynamics, the tea releases heat, which is received by the glass cup until thermal equilibrium is reached. The following formula represents the model under assumption that process was at steady state:

[tex]\rho_{w}\cdot V\cdot c_{w}\cdot (T_{w,o}-T) + m_{g}\cdot c_{g}\cdot (T_{g,o}-T) = 0[/tex] (1)

Where:

[tex]\rho_{w}[/tex] - Density of water, in grams per mililiter.

[tex]V[/tex] - Volume of tea, in mililiters.

[tex]c_{w}[/tex] - Specific heat of water, in joules per gram-degree Celsius.

[tex]m_{g}[/tex] - Mass of the glass cup, in kilograms.

[tex]c_{g}[/tex] - Specific heat of the glass cup, in joules per gram-degree Celsius.

[tex]T_{w,o}[/tex] - Initial temperature of tea, in degrees Celsius.

[tex]T_{g,o}[/tex] - Initial temperature of the glass cup, in degrees Celsius.

[tex]T[/tex] - Final temperature of the tea-cup system, in degrees Celsius.

If we know that [tex]\rho_{w} = 1\,\frac{g}{mL}[/tex], [tex]V = 200\,mL[/tex], [tex]c_{w} = 4.186\,\frac{J}{g\cdot ^{\circ}C}[/tex], [tex]m_{g} = 400\,g[/tex], [tex]c_{g} = 0.840\,\frac{J}{g\cdot ^{\circ}C}[/tex], [tex]T_{w,o} = 90\,^{\circ}C[/tex] and [tex]T_{g,o} = 25\,^{\circ}C[/tex], then the final temperature of the tea-cup system is:

[tex]\rho_{w}\cdot V\cdot c_{w}\cdot (T_{w,o}-T) + m_{g}\cdot c_{g}\cdot (T_{g,o}-T) = 0[/tex]

[tex]\rho_{w}\cdot V\cdot c_{w}\cdot T_{w,o} +m_{g}\cdot c_{g}\cdot T_{g,o} - (\rho_{w}\cdot V\cdot c_{w}+m_{g}\cdot c_{g})\cdot T = 0[/tex]

[tex]T = \frac{\rho_{w}\cdot c_{w}\cdot T_{w,o}+m_{g}\cdot c_{g}\cdot T_{g,o}}{\rho_{w}\cdot V\cdot c_{w}+m_{g}\cdot c_{g}}[/tex]

[tex]T = \frac{\left(1\,\frac{g}{mL} \right)\cdot \left(4.186\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (200\,mL)\cdot (90\,^{\circ}C)+(400\,g)\cdot \left(0.840\,\frac{J}{g\cdot ^{\circ}C} \right)\cdot (25\,^{\circ}C)}{\left(1\,\frac{g}{mL} \right)\cdot \left(4.186\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (200\,mL) +(400\,g)\cdot \left(0.840\,\frac{J}{g\cdot ^{\circ}C} \right)}[/tex]

[tex]T = 41.657\,^{\circ}C[/tex]

The final temperature of the system is 41.657 °C.

Answer:

Explanation: as,

v=f∧

v=200×10³×1.5×10³

v=2.7×10^7ms⁻¹

The velocity of the radio waves is 3 × 10⁸ ms⁻¹.

A radio station frequency = 200 KH

wavelength = 1.5 km

         Radio waves in the electromagnetic spectrum has the longest wavelength and it will always be below 300GHz. The radio waves can be generated with acceleration through some charged particles. Only through the transmitter via antenna the radio waves can gets transmitted. Radio waves can be used in all the electronic devices as mobile phones, radio communication, radars and navigations.

                               V = f λ

            Velocity,  v = ( 200 × 10³ ) × ( 1.5 × 10³ )

                               = ( 300 × 10⁶ )

                             v = 3 × 10⁸ ms⁻¹.

Hence, the velocity of the radio waves is 3 × 10⁸ ms⁻¹.

Learn more about the radio waves,

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#SPJ2

Answer:

drop in water

Explanation:

follow me m mm m

Answer:

The beam balance is a device used for the determination of the mass of a body under gravitation. Beam balance is used for high precision measurements like masses up to 250g, it consists of a pair of scale pans one at each end of a rigid beam.

we use a scale to measure the weight of our bodies

Answer:

Slowly and smoothly lol

Answer:

S.I. on Rs. 1600 = T.D. on Rs. 1680. Rs. 1600 is the P.W. of Rs. 1680, i.e., Rs. 80 is on Rs. 1600 at 15%. Time =100 x 80year=1year = 4 months.1600 x 153

Explanation:

Is this you are?

Using 3rd equation of kinematics

[tex]\boxed{\Large{\sf v^2-u^2=2as}}[/tex]

[tex]\\ \Large\sf\longmapsto v^2=u^2+2as[/tex]

[tex]\\ \Large\sf\longmapsto v^2=24^2+2(4)(96)[/tex]

[tex]\\ \Large\sf\longmapsto v^2=576+768[/tex]

[tex]\\ \Large\sf\longmapsto v^2=1344[/tex]

[tex]\\ \Large\sf\longmapsto v=\sqrt{1344}[/tex]

[tex]\\ \Large\sf\longmapsto v=36.6m/s[/tex]

Explanation:

C. Both energy and matter

Answer:

1) Motion of air mass moving from equator northward (closer to earth axis)

2) Motion of object in orbit

3) Collision of 2 objects

4) Skater changing rotation by extension of arms

5) Motion of rocket due to velocity of expelled gas

Answer:

resistances is inversely proportional to the area of cross section of the conductor

Explanation:

The resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area.

hope this helps you

have a nice day:)

Answer:

just add co-ratios and then find the average.

Explanation:

Answer:

Explanation:

The main equation to solve this is F = ma, where F is the force applied to the brakes with respect to its acceleration. We have the mass that we need, but we do not have the acceleration. That's the first thing we have to find. However, our velocity needs to be stated in m/s and right now it's in km/h. Converting that:

[tex]90\frac{km}{hr}*\frac{1000m}{1km}*\frac{1hr}{3600s} =25\frac{m}{s}[/tex] Now we're ready to find the acceleration:

[tex]a=\frac{v_f-v_0}{t}[/tex] where the top line there translates to the final velocity minus the initial velocity.

[tex]a=\frac{0-25}{3.0}[/tex] so the acceleration is -8.3 m/s/s

We can use that now in the force equation above:

F = 1200(-8.3) and

F = -1.0 × 10⁴ N (that's 10,000 N to the correct number of sig dig's; the negative sign means that the force is being applied in the direction opposite to that which the van is currently moving)

Answer: There are multiple options:

By varying the supply voltage.

By varying the flux, and by varying the current through the field winding.

By varying the armature voltage, and by varying the armature resistance.

Helpful Link:

https://www.elprocus.com/what-are-the-best-ways-to-control-the-speed-of-dc-motor/

Answer:

Explanation:

By being close to an atom that will gladly take the electrons being offered.

Suppose you are talking about Be. It is in the second column. It has two outer electrons that can be given away. It will not give away one of the two remaining electrons because they are too close to the + nucleus.

Along comes a Fluorine atom. It has 7 electrons in its outer ring. The chemistry of the situation allows it to take on one of the two electrons Be is offering. It is all a matter of charges and attractions.

Another Fluorine atom will take on the remaining electron from the Be. The outer ring cannot take on more than 1 electron, but that is enough

Answer:

I THINK IT'S D....

HOPE SO

Answer:

The northern lights come from the interaction of electrically charged particles given off by the Sun surface during solar storms and the Earth's magnetic field which is pointed in the northern to southern poles of the Earth. Therefore, the charged particles that travel through millions of miles from the Sun to the Earth accelerate towards the magnetic poles and appear as the northern (and southern) lights

Boreal is an adjective word for the north or northern regions. In the southern latitudes, in the southern hemisphere, the phenomenon is called aurora australis (australis is the adjective for 'of the south')

Explanation:

Using first equation of kinematics

[tex]\boxed{\sf v=u+at}[/tex]

[tex]\\ \sf\longmapsto t=\dfrac{v-u}{a}[/tex]

[tex]\\ \sf\longmapsto t=\dfrac{30-6}{4}[/tex]

[tex]\\ \sf\longmapsto t=\dfrac{24}{4}[/tex]

[tex]\\ \sf\longmapsto t=6s[/tex]

Answer:

1.12 × 10⁴ m/s

Explanation:

The escape velocity of the object v = √(2GM/R) where G = gravitational constant = 6.67 × 10⁻¹¹ Nm²/kg², M = mass of the Earth = 6 × 10²⁴ kg and R = radius of the Earth = 6.4 × 10⁶ m

Since v = √(2GM/R)

Substituting the values of the variables into the equation, we have

v = √(2GM/R)

v = √(2 × 6.67 × 10⁻¹¹ Nm²/kg² × 6 × 10²⁴ kg/6.4 × 10⁶ m)

v = √(13.34 × 10⁻¹¹ Nm²/kg² × 6 × 10²⁴ kg/6.4 × 10⁶ m)

v = √(80.04 × 10⁻¹¹ × 10²⁴Nm²/kg/6.4 × 10⁶ m)

v = √(80.04 × 10¹³Nm²/kg ÷ 6.4 × 10⁶ m)

v = √(80.04 ÷ 6.4 × 10¹³ ÷ 10⁶Nm/kg)

v = √(12.50625 × 10⁷ Nm/kg)

v = √(125.0625 × 10⁶ Nm/kg)

v = 11.18 × 10³ m/s

v = 1.118 × 10 × 10³ m/s

v = 1.118 × 10⁴ m/s

v ≅ 1.12 × 10⁴ m/s

Answer:

DU = -80 Joules

Explanation:

Given the following data;

Work done = 100 J

Quantity of heat = 20 J

To find change in internal energy of the gas;

Mathematically, the change in internal energy of a system is given by the formula;

DU = Q - W

Where;

DU is the change in internal energy.

Q is the quantity of energy.

W is the work done.

Substituting the values into the formula, we have;

DU = 20 - 100

DU = -80 Joules

Therefore, the final energy of the gas is lower than its initial energy.

Answer:

Explanation:

Here,

Final mass(m)=150g

Final Temperature(t)=60°C

Temperature of hot water(t1)=90C

Temperature of cold water(t2)=14C

Let the grams of water to be used per face be m1 grams and (150-m1) grams for hot and cold water respectively.

We know that,

Heat lost by hot body=Heat gained by cold body

or, m1 s1 Δt1=m2 s2 Δt2

or, m1 (t1-t)=(150-m1) (t-t2)  [∵s1=s2, SHC of water is taken to be same]

or, m1 (90-60)=(150-m1) (60-14)

or, 30m1=6900-46m1

or, 76m1=6900

∴m1=90.79g

(150-m1)=59.21g

Hence, 90.79g and 59.21 g hot and cold water must be used respectively.

Explanation:

(b) A uniform beam 150cm long weighs 3.5kg and

supported on knife-edges at its ends. The beam

supports a weight 7kg at a distance 30cm from

one end. Find the reactions of the supports.

Answer:It has 8550 j energy

Answer:

w = 0.01 t⁻²   rad/h

Explanation:

Let's use trigonometry to find the elevation angle of the telescope, we assume that the rocket remains fixed in the telescope.

        tan θ = CO / CA

the adjacent leg is CA = 16 km = 16 10³ m

Let's use kinematics to find the height of the rocket

          v = y / t

          y = v t

this height is equal to the opposite leg

          CO = v t

we substitute

         tan θ = vt / 16

         tan θ = 1200/16 t

         tan θ = 75 t

         θ = tan⁻¹ ( 75 t )

speed is defined by

          w = dθ/dt

          w = [tex]\frac{1}{1 + (75 t)^2} \ 75[/tex]  

as time increases we can neglect the 1 of the denominator

          w = 1/75 t²

          w = 0.0133 t⁻²

Using three significant figures

           w = 0.01 t⁻²   rad/h

for this answer the time must be given in hours

Explanation:

tilting it will raise the height of its center of gravity.

Answer:

The time taken is 1.76 s.

Explanation:

mass of student, m = 45 kg

height, h = 6 m

power, P = 1500 W

Power is defined as the rate of doing work.

Work done in moving height is

W = m g h

Let the time is t.

P = m g h / t

1500 = 45 x 9.8 x 6 / t

t = 1.76 s

Answer:

Momentum = 100 Kgm/s

Explanation:

Given the following data;

Speed = 72 km/h

Mass = 5 kg

To find the momentum of the stone;

First of all, we would have to convert the value of speed to meter per seconds.

Conversion:

72 km/h to m/s = (72 * 1000)/3600 = 20 m/s

Momentum can be defined as the multiplication (product) of the mass possessed by an object and its velocity. Momentum is considered to be a vector quantity because it has both magnitude and direction.

Mathematically, momentum is given by the formula;

Momentum = mass * velocity

Substituting the values into the formula, we have;

Momentum = 5 * 20

Momentum = 100 Kgm/s

Answer:

Organic farming would have higher costs, and would be more complex than conventional farming. However, the Suarez family could charge a higher price for organic produce. This type of farming also would be better for the land.

Explanation:

Answer expert verified for the same question. (question/4178423)

Answer:

a)  [tex]h=25m[/tex]

b)  [tex]v=19.8m/sec[/tex]

Explanation:

From the question we are told that:

Height [tex]h=25m[/tex]

Bounce Height [tex]h'=20m[/tex]

Generally the Kinematic equation is mathematically given by

[tex]V=\sqrt{2gh}\\\\V=\sqrt{2*9.81*25}[/tex]

[tex]V=22.1m/sec[/tex]

Therefore Height

[tex]h=\frac{V^2}{2g}\\\\h=\frac{22.1^2}{2*9.81}[/tex]

[tex]h=25m[/tex]

b)

Generally the Kinematic equation is mathematically given by

[tex]v^2=2ah[/tex]

[tex]v^2=2*9.8*20[/tex]

[tex]v=\sqrt{2*9.8*20}[/tex]

[tex]v=19.8m/sec[/tex]