USE THE PICTURE THANKS WILL GIVE B WRONG ANSWER=report lol love ya

Energy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is one kilocalorie, defined as 1 kc

Sergeeva-Olga [200]

Answer:

a) The student must run flight of stairs to lose 1.00 kg of fat 709.5 times.

b) Average power

P(w)= 1062.07 [w]

P(hp)=1.42 [hp]

c) This activity is highly unpractical, because the high amount of repetitions he has to due in order to lose, just 1 Kg of fat.

Explanation:

First, lets consider the required amount of work to move the mass of the student. (considering running stairs just as a vertical movement)

Work:

$W= F*d= m*g*d$

Where m is the mass of the student, g is gravity (9.8 m/s) and d is the total distance going up the stairs (0.15m *85steps= 12.75m )

$W= F*d= m*g*d=85* 9.8*12.75=10620.75 [J]$

Converting from Joules to Kcals:

$\frac{10620.75}{4186} =2.537 Kcal$

Now lets take into account the efficiency of the human body (20%)

2.537 ---> 20%

x ---> 100%

$x=\frac{2.537*100}{20} =12.685$

So the student is consuming 12.685 KCals each time he runs up the stairs.

Now,

1 g --> 9 Kcals

1000 g --> 9000KCals

Burning 1 g of fat, requieres 9 KCals, 1000g burns 9000KCals. So in order to burn a 1Kg of fat:

$\frac{9000Kcals}{12.685Kcals} =709.5 times$

He must run up the stairs 709.5 times, to burn 1 Kg of fat.

********************

For b) just converting units, taking into account the time lapse. (53103.75 is the 100% of the energy in joules, from converting 12.685Kcals to joules)

$Power=\frac{Joules}{Seconds} =\frac{53103.75}{50} =1062.075 [W]\\$

$P(hp)=\frac{P(w)}{745.7} =\frac{1062.075}{745.7} =1.42[hp]$

*****

4 0

3 years ago

Why do aeroplanes take longer to fly west than east?

PolarNik [594]

Every planet/moon has global wind that are mostly determined by the way the planet/moon rotates and how evenly the Sun illuminates it. On the Earth the equator gets much more Sun than the poles. resulting in warmer air at the equator than the poles and creating circulation cells (or "Hadley Cells") which consist of warm air rising over the equator and then moving North and South from it and back round.

The Earth is also rotating. When any solid body rotates, bits of it that are nearer its axis move slower than those which are further away. As you move north (or south) from the equator, you are moving closer to the axis of the Earth and so the air which started at the equator and moved north (or south) will be moving faster than the ground it is over (it has the rotation speed of the ground at the equator, not the ground which is is now over). This results in winds which always move from the west to the east in the mid latitudes.

8 0

3 years ago

Which statements are true for two oppositely charged, isolated parallel plates: C=capacitance, U=stored energy (Q and -Q = charg

vlada-n [284]

Answer:

Explanation:

1) True. The stored energy (U) is proportional to the electric field strength (E). The electric field strength decreases when a dielectric is introduced hence inserting a dielectric decreases U.

2) False. From the formula $C=\frac{Q}{V}=\frac{Q}{Vd}$ , capacitance is inversely proportional to distance hence if the distance is doubled, capacitance decreases.

3) False. As the distance between the electric field and the object increases, its electric field decreases.

4) False. If a dielectric is inserted, the plates are further separated. Q stays the same.

5) True. The electric field strength decreases when a dielectric is introduced and capacitance is inversely proportional to electric field hence Inserting a dielectric increases C

6) True. If a dielectric is inserted, the plates are further separated. Q stays the same.

7) True. When the distance is doubled, U increases

7 0

2 years ago

a circular loop is hanging on the wall. it has a radius of 33.3 cm and is comprised of 12 coils. there is a magnetic field perpe

Vika [28.1K]

Answer:

I = 2.19A, anticlockwise direction.

Explanation:

Given r = 33cm = 0.33m, N = 12, ΔB = 7.5 - 1.5 = 6.0T, Δt = 3s, R = 3.75Ω

By Faraday's law of electromagnetic induction when there is a change in flux in a coil or loop, an emf is induced in the coil or loop which is proportional to the time rate of change of the magnetic flux through the loop.

The emf E is related to the flux by the formula

E = – NdФ/dt

Where N = number of turns in the coil, Ф = magnetic flux through the loop = BA, B = magnetic field strength, A = Area

In this problem the strength of the magnetic field changes. As a result the flux too changes and an emf is induced in the coil.

So

ΔФ = ΔB×A = ΔB×πr² = 6×π×0.33² = 2.05Wb

E = -NΔФ/Δt = 12×2.05/3 = 8.2V

I = E/R = 8.2/ 3.75 = 2.19A

The direction of the current can be found by pointing the thumb of your right hand in the direction of the magnetic field and curling the remaining fingers around this direction. The direction of the curl of these fingers give the direction of current which in this case is anticlockwise.

5 0

3 years ago

What are examples of devices that use electromagnetic waves? Check all that apply.

yKpoI14uk [10]

Well, there aren't actually ANY that apply, because you haven't listed any. But I've lived a long time, and I remember hearing about electromagnetic waves and things that use them, so I can list a FEW of them for you:

-- radios

-- TVs

-- garage-door openers

-- TV remotes

-- cell phones

-- smart phones

-- GPS

-- walkie-talkies

-- car headlights

-- lava lamps

-- toasters

-- LEDs

-- light bulbs

-- fluorescent light tubes

-- police radios

-- Doppler weather radars

-- CB radios

-- ham radios

-- neon signs

-- eyeglasses

-- microscopes

-- telescopes

-- gas stoves

-- electric stoves

-- wood stoves

-- microwave ovens

-- tanning beds

-- cameras

-- lasers

-- CD recorders and players

-- DVD recorders and players

-- Bluray recorders and players

-- movie cameras

-- movie projectors

-- reading lamps

-- candles

-- whale-oil lamps

-- kerosene lanterns

-- flashlights

-- campfires

-- coffee percolators

-- heat lamps

-- cordless phones

These are just the ones I can think of right now off the top of my head. There are a lot of others.

5 0

3 years ago

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