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photoshop1234 [79]
3 years ago
9

Driving on asphalt roads entails very little rolling resistance, so most of the energy of the engine goes to overcoming air resi

stance. But driving slowly in dry sand is another story. If a 1500 kg car is driven in sand at 4.9 m/s , the coefficient of rolling friction is 0.060. In this case, nearly all of the energy that the car uses to move goes to overcoming rolling friction, so you can ignore air drag in this problem.
Required:
a. What propulsion force is needed to keep the car moving forward at a constant speed?
b. What power is required for propulsion at 5.0 m/s?
c. If the car gets 15 mpg when driving on sand, what is the car's efficiency? One gasoline contains 1.4×10 ^8 J of chemical energy.
Physics
1 answer:
trapecia [35]3 years ago
7 0

Answer:

a)  F_p=882N

b)  P=4410W

c)  V_p'=24135 ,n=15.2\%

Explanation:

From the question we are told that:

Mass M=1500kg

Velocity v=4.9m/s

Coefficient of Rolling Friction \mu=0.06

a)

Generally the equation for The Propulsion Force is mathematically given by

 F_p=\mu*mg

 F_p=0.06*1500*9.81

 F_p=882N

b)

Therefore Power Required at

 V_p=5.0m/s

 P=F_p*V_p

 P=882*5

 P=4410W

c)

 V_p' =15mpg

 V_p'=15*\frac{1609}

 V_p'=24135

Generally the equation for Work-done is mathematically given by

 W=F_p*V_p'

 W=882*15*1609

 W=2.13*10^7

Therefore

Efficiency

 n=\frac{W}{E}*100\%

Since

Energy in one gallon of gas is

 E=1.4*10^8J

Therefore

 n=\frac{2.1*10^7}{1.4*10^8}*100\%

 n=15.2\%

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The circuit you should use to find the open-circuit voltage is
fiasKO [112]

Answer:

Incomplete questions check attachment for circuit diagram.

Explanation:

We are going to use superposition

So, we will first open circuit the current source and find the voltage Voc.

So, check attachment for open circuit diagram.

From the diagram

We notice that R3 is in series with R4, so its equivalent is given below

Req(3-4) = R3 + R4

R(34) = 20+40 = 60 kΩ

Notice that R2 is parallel to the equivalent of R3 and R4, then, the equivalent of all this three resistor is

Req(2-3-4) = R2•R(34)/(R2+R(34))

R(234) = (100×60)/(100+60)

R(234) = 37.5 kΩ

We notice that R1 and R(234) are in series, then, we can apply voltage divider rule to find voltage in R(234)

Therefore

V(234) = R(234) / [R1 + R(234)] × V

V(234) = 37.5/(25+37.5) × 100

V(234) = 37.5/62.5 × 100

V(234) = 60V.

Note, this is the voltage in resistor R2, R3 and R4.

Note that, R2 is parallel to R3 and R4. Parallel resistor have the same voltage, then voltage across R2 equals voltage across R34

V(34) = 60V.

Now, we also know that R3 and R4 are in series,

So we can know the voltage across R4 which is the Voc we are looking for.

Using voltage divider

V4 = Voc = R4/(R4 + R(34)) × V(34)

Voc = 40/(40+60) × 60

Voc = 24V

This is the open circuit Voltage

Now, finding the short circuit voltage when we short circuit the voltage source

Check attachment for circuit diagram.

From the circuit we notice that R1 and R2 are in parallel, so it's equivalent becomes

Req(1-2) = R1•R2/(R1+R2)

R(12) = 25×100/(25+100)

R(12) = 20 kΩ

We also notice that the equivalent of Resistor R1 and R2 is in series to R3. Then, the equivalent resistance of the three resistor is

Req(1-2-3) = R(12) + R(3)

R(123) = 20 + 20

R(123) = 40 kΩ

We notice that, the equivalent resistance of the resistor R1, R2, and R3 is in series to resistor R4.

So using current divider rule to find the current in resistor R4.

I(4) = R(123) / [R4+R(123)] × I

I(4) = 40/(40+40) × 8

I(4) = 4mA

Then, using ohms law, we can find the voltage across the resistor 4 and the voltage is the required Voc

V = IR

V4 = Voc = I4 × R4

Voc = 4×10^-3 × 40×10^3

Voc = 160V

Then, the sum of the short circuit voltage and the open circuit voltage will give the required Voc

Voc = Voc(open circuit) + Voc(short circuit)

Voc = 24 + 160

Voc = 184V.

3 0
3 years ago
WILL GIVE BRAINLIST QUICK!!! How does biodiversity support different varieties of species? (please put short answer)
Kay [80]
Biodiversity boosts ecosystem productivity where each species, no matter how small, all have an important role to play.A larger number of plant species means a greater variety of crops. Greater species diversity ensures natural sustainability for all life forms.
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3 years ago
Explain why asleel meedle does not csink on water​
Juli2301 [7.4K]

Answer:

upthrust

Explanation:

i think it does not sink in water because of the force pulling it upwards

5 0
2 years ago
What is the process called when the moon begins to fade from a full moon to the new moon?
satela [25.4K]

Answer: Waning

Explanation: Not much explanation for this

8 0
3 years ago
A wire, 1.0 m long, with a mass of 90 g, is under tension. A transverse wave is propagated on the wire, for which the frequency
Mice21 [21]

Answer:

T = 712.9 N

Explanation:

First, we will find the speed of the wave:

v = fλ

where,

v = speed of the wave = ?

f = frequency = 890 Hz

λ = wavelength = 0.1 m

Therefore,

v = (890 Hz)(0.1 m)

v = 89 m/s

Now, we will find the linear mass density of the wire:

\mu = \frac{m}{L}

where,

μ = linear mass density of wie = ?

m = mass of wire = 90 g = 0.09 kg

L = length of wire = 1 m

Therefore,

\mu = \frac{0.09\ kg}{1\ m}

μ = 0.09 kg/m

Now, the tension in wire (T) will be:

T = μv² = (0.09 kg/m)(89 m/s)²

<u>T = 712.9 N</u>

7 0
3 years ago
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