1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
satela [25.4K]
3 years ago
15

What simple machines combine to make a shovel which is a compound

Physics
1 answer:
IRINA_888 [86]3 years ago
6 0
B) lever and pulley is the answer
You might be interested in
A rigid, insulated tank whose volume is 10 L is initially evacuated. A pinhole leak develops and air from the surroundings at 1
balandron [24]

Answer:

The answer is "143.74^{\circ} \ C , 8.36\ g, and \ 2.77\ \frac{K}{J}"

Explanation:

For point a:

Energy balance equation:

\frac{dU}{dt}= Q-Wm_ih_i-m_eh_e\\\\

W=0\\\\Q=0\\\\m_e=0

From the above equation:

\frac{dU}{dt}=0-0+m_ih_i-0\\\\\Delta U=\int^{2}_{1}m_ih_idt\\\\

because the rate of air entering the tank that is h_i constant.

\Delta U = h_i \int^{2}_{1} m_i dt \\\\= h_i(m_2 -m_1)\\\\m_2u_2-m_1u_2=h_i(M_2-m_1)\\\\

Since the tank was initially empty and the inlet is constant hence, m_2u-0=h_1(m_2-0)\\\\m_2u_2=h_1m_2\\\\u_2=h_1\\\\

Interpolate the enthalpy between T = 300 \ K \ and\ T=295\ K. The surrounding air  

temperature:

T_1= 25^{\circ}\ C\ (298.15 \ K)\\\\\frac{h_{300 \ K}-h_{295\ K}}{300-295}= \frac{h_{300 \ K}-h_{1}}{300-295.15}

Substituting the value from ideal gas:

\frac{300.19-295.17}{300-295}=\frac{300.19-h_{i}}{300-298.15}\\\\h_i= 298.332 \ \frac{kJ}{kg}\\\\Now,\\\\h_i=u_2\\\\u_2=h_i=298.33\ \frac{kJ}{kg}

Follow the ideal gas table.

The u_2= 298.33\ \frac{kJ}{kg} and between temperature T =410 \ K \ and\  T=240\ K.

Interpolate

\frac{420-410}{u_{240\ k} -u_{410\ k}}=\frac{420-T_2}{u_{420 k}-u_2}

Substitute values from the table.

 \frac{420-410}{300.69-293.43}=\frac{420-T_2}{{u_{420 k}-u_2}}\\\\T_2=416.74\ K\\\\=143.74^{\circ} \ C\\\\

For point b:

Consider the ideal gas equation.  therefore, p is pressure, V is the volume, m is mass of gas. \bar{R} \ is\  \frac{R}{M} (M is the molar mass of the  gas that is 28.97 \ \frac{kg}{mol} and R is gas constant), and T is the temperature.

n=\frac{pV}{TR}\\\\

=\frac{(1.01 \times 10^5 \ Pa) \times (10\ L) (\frac{10^{-3} \ m^3}{1\ L})}{(416.74 K) (\frac{8.314 \frac{J}{mol.k} }{2897\ \frac{kg}{mol})}}\\\\=8.36\ g\\\\

For point c:

 Entropy is given by the following formula:

\Delta S = mC_v \In \frac{T_2}{T_1}\\\\=0.00836 \ kg \times 1.005 \times 10^{3} \In (\frac{416.74\ K}{298.15\ K})\\\\=2.77 \ \frac{J}{K}

5 0
3 years ago
Which of the following is true about all electromagnetic waves in a vacuum
Helen [10]
Electro waves in a vacuum air is deals with this and electricity when the air and the electricity it  makes electro magnets.
4 0
4 years ago
Read 2 more answers
If the speed of sound in air is 343 m/s and the wavelength of this note is 2.62 m, what is the frequency of this C3 note? (Round
snow_lady [41]

Answer:

<em>The frequency of of the note = 131 Hz.</em>

Explanation:

<em>Frequency:</em><em> Frequency can be defined as the number of complete oscillation completed by a wave in one seconds. The S.I unit of frequency is Hertz ( Hz)</em>

v = λf ............................ Equation 1

Making f the subject of the equation,

f = v/λ .......................... Equation 2

Where v = Speed, λ = wavelength, f = frequency

<em>Given: v = 343 m/s, λ = 2.62 m.</em>

<em>Substituting these values into equation 2</em>

<em>f = 343/2.62</em>

<em>f = 131 Hz</em>

<em>Thus the frequency of of the note = 131 Hz.</em>

8 0
3 years ago
The speed of light in a vacuum is 299,792,458 m/s. Which gives this number in three significant digits? 299,000,000. m/s 2.99 x
dexar [7]

Answer: 2.99(10)^{-8} m/s

Explanation:

When a number is written in scientific notation (representing the number using powers of base ten) it is expressed so that it contains a digit in the place of the units and all other digits after the decimal point, multiplied by the respective exponent.  

Then, the significant figures (or significant digits) will be the digits that are before the power of ten.  

Now, in the case of the number 299,792,458 if we want to write it with three significant digits, we have to write it in scientific notation as:

2.99(10)^{-8}

7 0
3 years ago
Read 2 more answers
I need to lift a 2000kg car, 1.798m and the joules required is 35240.8. Converted to watt (W = 35240.8/5 (s)) I got 7048.16 W. I
marusya05 [52]
This is a very interesting problem ... mainly because it's different from
the usual questions in the Physics neighborhood.

I can discuss it with you, but maybe not quite give you a final answer
with the information you've given in the question.

I agree with all of your calculations so far ... the total energy required,
and the power implied if the lift has to happen in 5 seconds.

First of all, let's talk about power.  I'm assuming that your battery is
a "car" battery, and I'm guessing you measured the battery voltage
while the car was running.  Turn off the car, and you're likely to read
something more like 13 to 13.8 volts.
But that's not important right now.  What I'm looking for is the CURRENT
that your application would require, and then to look around and see whether
a car battery would be capable of delivering it.

   Power = (volts) x (current)

   7,050 W  =  (14 volts) x (current)

   Current = (7,050 watts / 14 volts) =  503 Amperes. 

That kind of current knocks the wind out of me.  I've never seen
that kind of number outside of a power distribution yard.
BUT ... I also know that the current demand from a car battery during
starting is enormous, so I'd better look around online and try to find out
what a car battery is actually capable of.

I picked a manufacturer's name that I'd heard of, then picked their
recommended battery for a monster 2003-model car, and looked at
the specs for the battery.

The spec I looked at was the 'CCA' ... cold cranking Amps.
That's the current the battery is guaranteed to deliver for 30 seconds,
at a temperature of 0°F, without dropping below 12 volts.

This battery that I saw is rated  803 Amps  CCA !

OK.  Let's back up a little bit.  I'm pretty sure the battery you have
is a nominal "12-volt" battery.  Let's say you use to start lifting the lift. 
As the lift lifts, the battery voltage sags.  What is the required current
if the battery immediately droops to 12V and stays there, while delivering
7,050 watts continuously ?

          Power = (volts) x (current)

          7,050 W = (12 V) x (current)

            Current = (7,050 W / 12 V)  =  588 Amps . 

Amazingly, we may be in the ball park.
If the battery you have is rated by the manufacturer for 600 Amps
CCA (0°F) or CA (32°F), then the battery can deliver the current
you need.
BUT ... you can't conduct that kind of current through ear-bud wire,
or house wiring wire.  I'm not even so sure of jumper-cables. 
You need thick, no-nonsense cable, AND connections with a lot of
area ... No alligator clips.  Shiny nuts and bolts with no crud on them.

Now ... I still want to check the matter of the total energy.
I'm sure you're OK, because the CCA and CA specifications talk about
30 seconds of cranking, and you're only talking about 5 seconds of lifting.
But I still want to see the total energy requirement compared to the typical
battery specification ... 'AH' ... ampere-hours.

You're talking about 35,000 joules

                          = 35,000 watt-seconds

                         =  35,000 volt-amp-seconds.

               (35,000 volt-amp-sec) x (1 hour/3600 sec) / (12 volt)               

           =  (35,000 x 1) / (3600 x 12)  volt-amp-sec-hour / sec-volt

           =    0.81 Amp-Hour  .

That's an absurdly small depletion from your car battery.
But just because it's only  810 mAh, don't get the idea that you can
do it with a few rechargeable AA batteries out of your camera.
You still need those 600 cranking amps.  That would be a dead short
for a stack of camera batteries, and they would shrivel up and die.

Have I helped you at all ?
5 0
3 years ago
Other questions:
  • A battery has an emf of 15.0 V. The terminal voltage of the battery is 12.2 V when it is delivering 14.0 W of power to an extern
    10·1 answer
  • Platinum has a density of 21 g/cm3. A platinum ring is placed in a graduated cylinder that contains water. The water level rises
    10·2 answers
  • What is the same person's mass on mars, where the acceleration due to gravity is 3.7 m/s2?
    12·1 answer
  • Please help me with this question
    11·1 answer
  • The sprinter ran 110 m in 11 seconds. What was her average speed in m/s?
    12·2 answers
  • Four boys push on the front back and sides of a shopping cart. the boys in the front on the two sides push with a force of 60N.
    13·1 answer
  • A cat has a mass of 3 kg and runs at a speed of 6 m/s. How much kinetic
    13·2 answers
  • Which best describes a radioactive isitope
    8·1 answer
  • Explain how conduction, convection, and radiation occur involving a campfire
    9·1 answer
  • Which of the following, by scientific definition is NOT work? lifting boxes of books, pedaling on your bike, holding a book over
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!