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mel-nik [20]
2 years ago
10

An elevator is rising up a vertical shaft in a skyscraper. Between the 12th and 20th floors, it travels at a constant speed. Dur

ing this time period:
1.) The only unbalanced force acting on it is air resistance.

2.) The forces acting on it are balanced so the net force is zero.

3.) The upward force is greater than the combined downward forces of gravity and air resistance, making it move upward.

4.) There are no forces acting on it so the net force is zero.
Physics
1 answer:
zaharov [31]2 years ago
8 0
3. The upward force is greater
.................,
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Carbon dioxide (CO2) gas in a piston-cylinder assembly undergoes three processes in series that begin and end at the same state
topjm [15]

Answer:

a) W =400 kJ

b) W = 0 kJ

c) W =-160.944 KJ

Explanation:

<u>Given  </u>

<u><em>Process 1 ---> 2 </em></u>

The relation of the process P = constant

Pressure of point (1) P1 =  10 bar = P2

Volume of point (1) V1   = 1 m^3

Volume of point (2) V2 =4 m^3

The relation of the process V = constant  

<u>Process 2 ---> 3 </u>

The relation of the process V = constant

V3 = V2

Pressure of point (3) P3 = 10 bar

Volume of point (3) V3 = 4 m^3

<u>Process 3 ---> 1 </u>

The relation of the process PV = constant  

<u>Required  </u>

Sketch the processes on the PV coordinates

The work for each process in kJ  

<u>Solution  </u>

The work is defined by  

W=\int\limits^a_b {x} \, dx

<em>a=V2</em>

<em>b=V1</em>

<em>x=P</em>

<em>dx=dV</em>

<u>Process 1 ---> 2  </u>

P3 = P4 = 5 bar  

W=\int\limits^a_b {x} \, dx

<em>a=V3</em>

<em>b=V2</em>

<em>x=4</em>

<em>dx=dV</em>

putting the value of a, b, x, dx in above integral

W=400 kJ

<u>Process 2 ---> 3 </u>

V = constant Then there is no change in the volume,hence W = 0 kJ  

<u>Process 3 ---> 1  </u>

By substituting with point (1) --> 5 x .2 = C ---> C = 1 P = 5V^-1  

 W=\int\limits^a_b {x} \, dx

a=V1

b=V3

x=1V^-1

dx=dV

putting the value of a, b, x, dx in above integral

W=| ln V | limit a and b

  = -160.944 KJ

5 0
3 years ago
A jet aircraft is traveling at 262 m/s in horizontal flight. The engine takes in air at a rate of 85.9 kg/s and burns fuel at a
Fittoniya [83]

Answer:

F_T=60132.52N

P=15814852.76W

Explanation:

From the question we are told that

Velocity of aircraft  V=263m/s

Engine air intake rate \triangle M_a=85.9kg/s

Fuel burn rate  \triangle M_f =3.92kg/s

Velocity of exhaust gas V_e =921m/s

Generally the Mass change rate of Rocket is mathematically given by

 \triangle M = \triangle M_a+\triangle M_f

 \triangle M= 85.9+3.92

 \triangle M=89.82kg/s

Generally the Trust of the rocket is given mathematically by

 F_T=(\triangle M *V_e)-(dM_a/dt)*(V)

 F_T=(89.82 *921)-(85.9)*(263)

 F_T=60132.52N

Generally the Rocket's delivered power is mathematically given by

Delivered power P

 P=V*F_T

 P=263*60132.52N

 P=15814852.76W.

8 0
2 years ago
About how long would it take a car driving at 17 m/s to travel 100 m? A. 4 s B. 5 s C. 6 s D. 7 s
Novay_Z [31]

5 s is the correct answer

6 0
2 years ago
How are magnetic forces like electric forces? (4 points) Select one: a. They both have charges b. In both, opposites attract. c.
nlexa [21]

Lets take it down a notch and break it down:

Magnetic forces and electric forces are quite similar, lets take a look at the answers possible:

A. They both have charges

False, magnetic forces do not HAVE charges, but they have an EFFECT on moving charges (that are creating a magnetic field around them).

Why? Electrical forces have positive and negative charges while magnetic forces have a north and south POLE. These two are different forces, therefore magnetic forces do not HAVE charges.

B. In both, opposites attract

We all know opposite poles attract, like poles, don't attract (repelling force). This is true for the magnetic force, now, the electric force, two positively charged particles will exert a repulsive force on one another. DING DING. We have a winner. <u>B is TRUE.</u>

C. In both, opposites repel

False, we already know in electric and magnetic forces that opposites attract and similar charges/poles repel.

D. Neither have charges

False, this is a joke question right? Don't even look at this one!!!!!!!!!


<u>Therefore, </u><u>B</u><u>, is the only true answer that describes how magnetic and electric forces are similar. </u>

Have a nice day!

6 0
3 years ago
True or false An example of a destructive force is the formation of mountains.
Bad White [126]

Answer:

i would say it is true

hope i helped

Explanation:

5 0
3 years ago
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