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Shkiper50 [21]
3 years ago
15

¿Alguien me puede ayudar? Problema: Un niño le pide gastada a su papá y éste le contesta que le dará los $120 que tiene en su bo

lsillo siempre y cuando conteste cuántas monedas de a $5 y de a $2 tiene en él si en total hay 33. ¿Qué debe contestar el niño si quiere los $120?
Physics
1 answer:
VLD [36.1K]3 years ago
3 0

Answer: there are 15 coins of $2 and 18 coins of $5

Explanation:

I will answer in English.

X is the number of $5 coins.

Y is the number of $2 coins.

We have the system of equations:

Y + X = 33

Y*2 + X*5 = 120

first, we must isolate one of the variables in one of the equations and then replace it in the other equation, let's isolate Y in the first equation:

Y = 33 - X.

Then we can replace it in the other equation:

(33 - X)*2 + X*5 = 120

66 - X*2 + X*5 = 120

X*3 = 54

X = 54/3 = 18

and using the equation for Y.

Y = 33 - X = 33 - 18 = 15

So there are 15 coins of $2 and 18 coins of $5

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Bumper of a stationary bumper car. The momentum of the stationary car increases. Which happens to the momentum of the moving bumper car? It decreases. It stays the same. It is converted to inertia.

Bumper of a stationary bumper car. The momentum of the stationary car increases. The momentum of the moving bumper car It is converted to inertia.

6 0
3 years ago
When the starter motor on a car is engaged, there is a 310 A current in the wires between the battery and the motor. Suppose the
Blababa [14]

Answer:

Diameter will be 351.42 mm

Explanation:

We have given current flowing in the copper wire i = 310 A

Voltage drop across the wire V = 0.55 volt

We know that resistance is given by R=\frac{V}{i}=\frac{0.55}{310}=0.00177\Omega

Length of the copper wire l = 1 m

Resisitivity of the copper wire \rho =1.72\times 10^{-8}\Omega m

We know that resistance R=\frac{\rho l}{A}

0.00177=\frac{1.72\times 10^{-8}\times  1}{A}

A=969.4545\times 10^{-8}m^2

As area A=\pi r^2

3.14\times r^2=969.4545\times 10^{-8}

r=17.57\times 10^{-4}m

So diameter d=17.57\times 10^{-4}\times 2=35.142\times \times 10^{-4}m = 351.42 mm

3 0
3 years ago
Why is a minimum of three seismic stations needed to find the epicenter of an earthquake?
vazorg [7]

Each station can detect how far away the epicenter was. So each station basically has a circle made of possible epicenters. When you have three, you narrow it down to one, final point.

5 0
3 years ago
Calculate the energy used by a radio of power 30W in 1 minute.
Alekssandra [29.7K]

Answer:

<u>1.8kJ</u>

Explanation:

Formula :

<u>Energy used = Power x time</u>

<u />

===============================================================

Given :

⇒ Power = 30 W

⇒ Time = 1 minute = 60 seconds

=============================================================

Solving :

⇒ Energy used = 30 W × 60 s

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2 years ago
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A flutist assembles her flute in a room where the speed of sound is 342 m/s. When she plays the note A, it is in perfect tune wi
sertanlavr [38]

Answer:

5.15348 Beats/s

4.55 mm

Explanation:

v_1 = Velocity of sound = 342 m/s

v_2 = Velocity of sound = 346 m/s

f_1 = First frequency = 440 Hz

Frequency is given by

f_2=\frac{v_2}{2L_1}\\\Rightarrow f_2=\frac{346}{2\times 0.38863}\\\Rightarrow f_2=445.15348\ Hz

Beat frequency is given by

|f_1-f_2|=|440-445.15348|=5.15348\ Beats/s

Beat frequency is 5.15348 Hz

Wavelength is given by

\lambda_1=\frac{v_1}{f}\\\Rightarrow \lambda_1=\frac{342}{440}\\\Rightarrow \lambda_1=0.77727\ m

Relation between length of the flute and wavelength is

\lambda_1=2L_1\\\Rightarrow L_1=\frac{\lambda_1}{2}\\\Rightarrow L_1=\frac{0.77727}{2}\\\Rightarrow L_1=0.38863\ m

At v = 346 m/s

\lambda_2=\frac{v_2}{f}\\\Rightarrow \lambda_2=\frac{346}{440}\\\Rightarrow \lambda_1=0.78636\ m

L_2=\frac{\lambda_2}{2}\\\Rightarrow L_2=\frac{0.78636}{2}\\\Rightarrow L_2=0.39318\ m

Difference in length is

\Delta L=L_2-L_1\\\Rightarrow \Delta L=0.39318-0.38863\\\Rightarrow \Delta L=0.00455\ m=4.55\ mm

It extends to 4.55 mm

7 0
3 years ago
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