Answer:
Llegara a su destino a la 1:00 pm
Explanation:
Si el coche va a 90 km/h buscamos un numero q al multiplicarlo por 90 nos de 450. Entonces 90×5 = 450, si hacemos la cuenta desde las ocho de la mañana mas las 5 horas del viaje terminaria llegando a su destino a la 1:00 pm.
Answer:
![v=(6ti+6k)\ m/s](https://tex.z-dn.net/?f=v%3D%286ti%2B6k%29%5C%20m%2Fs)
Explanation:
Given that,
The position of a particle is given by :
![r(t) = (3.0 t^2 i + 5.0j+ 6.0 tk) m](https://tex.z-dn.net/?f=r%28t%29%20%3D%20%283.0%20t%5E2%20i%20%2B%205.0j%2B%206.0%20tk%29%20m)
Let us assume we need to find its velocity.
We know that,
![v=\dfrac{dr}{dt}\\\\=\dfrac{d}{dt}(3.0 t^2 i + 5.0j+ 6.0 tk) \\\\=(6ti+6k)\ m/s](https://tex.z-dn.net/?f=v%3D%5Cdfrac%7Bdr%7D%7Bdt%7D%5C%5C%5C%5C%3D%5Cdfrac%7Bd%7D%7Bdt%7D%283.0%20t%5E2%20i%20%2B%205.0j%2B%206.0%20tk%29%20%5C%5C%5C%5C%3D%286ti%2B6k%29%5C%20m%2Fs)
So, the velocity of the particle is
.
Answer:
X₃₁ = 0.58 m and X₃₂ = -1.38 m
Explanation:
For this exercise we use Newton's second law where the force is the Coulomb force
F₁₃ - F₂₃ = 0
F₁₃ = F₂₃
Since all charges are of the same sign, forces are repulsive
F₁₃ = k q₁ q₃ / r₁₃²
F₂₃ = k q₂ q₃ / r₂₃²
Let's find the distances
r₁₃ = x₃- 0
r₂₃ = 2 –x₃
We substitute
k q q / x₃² = k 4q q / (2-x₃)²
q² (2 - x₃)² = 4 q² x₃²
4- 4x₃ + x₃² = 4 x₃²
5x₃² + 4 x₃ - 4 = 0
We solve the quadratic equation
x₃ = [-4 ±√(16 - 4 5 (-4)) ] / 2 5
x₃ = [-4 ± 9.80] 10
X₃₁ = 0.58 m
X₃₂ = -1.38 m
For this two distance it is given that the two forces are equal
Answer:
(c) 97 dB sound intensity level
Explanation:
We have given the intensity of the loud car horn ![I=0.005w/m^2](https://tex.z-dn.net/?f=I%3D0.005w%2Fm%5E2)
We know that ![I_O=10^{-12}w/m^2](https://tex.z-dn.net/?f=I_O%3D10%5E%7B-12%7Dw%2Fm%5E2)
Now the sound intensity level is given by
, which is nearly equal to 97
So the sound intensity level will be 97 dB
So option (c) will be the correct option
Answer:
Distance = 345719139.4[m]; acceleration = 3.33*10^{19} [m/s^2]
Explanation:
We can solve this problem by using Newton's universal gravitation law.
In the attached image we can find a schematic of the locations of the Earth and the moon and that the sum of the distances re plus rm will be equal to the distance given as initial data in the problem rt = 3.84 × 108 m
![r_{e} = distance earth to the astronaut [m].\\r_{m} = distance moon to the astronaut [m]\\r_{t} = total distance = 3.84*10^8[m]](https://tex.z-dn.net/?f=r_%7Be%7D%20%3D%20distance%20earth%20to%20the%20astronaut%20%5Bm%5D.%5C%5Cr_%7Bm%7D%20%3D%20distance%20moon%20to%20the%20astronaut%20%5Bm%5D%5C%5Cr_%7Bt%7D%20%3D%20total%20distance%20%3D%203.84%2A10%5E8%5Bm%5D)
Now the key to solving this problem is to establish a point of equalisation of both forces, i.e. the point where the Earth pulls the astronaut with the same force as the moon pulls the astronaut.
Mathematically this equals:
![F_{e} = F_{m}\\F_{e} =G*\frac{m_{e} *m_{a}}{r_{e}^{2} } \\](https://tex.z-dn.net/?f=F_%7Be%7D%20%3D%20F_%7Bm%7D%5C%5CF_%7Be%7D%20%3DG%2A%5Cfrac%7Bm_%7Be%7D%20%2Am_%7Ba%7D%7D%7Br_%7Be%7D%5E%7B2%7D%20%20%7D%20%5C%5C)
![F_{m} =G*\frac{m_{m}*m_{a} }{r_{m} ^{2} } \\where:\\G = gravity constant = 6.67*10^{-11}[\frac{N*m^{2} }{kg^{2} } ] \\m_{e}= earth's mass = 5.98*10^{24}[kg]\\ m_{a}= astronaut mass = 100[kg]\\m_{m}= moon's mass = 7.36*10^{22}[kg]](https://tex.z-dn.net/?f=F_%7Bm%7D%20%3DG%2A%5Cfrac%7Bm_%7Bm%7D%2Am_%7Ba%7D%20%20%7D%7Br_%7Bm%7D%20%5E%7B2%7D%20%7D%20%5C%5Cwhere%3A%5C%5CG%20%3D%20gravity%20constant%20%3D%206.67%2A10%5E%7B-11%7D%5B%5Cfrac%7BN%2Am%5E%7B2%7D%20%7D%7Bkg%5E%7B2%7D%20%7D%20%5D%20%5C%5Cm_%7Be%7D%3D%20earth%27s%20mass%20%3D%205.98%2A10%5E%7B24%7D%5Bkg%5D%5C%5C%20m_%7Ba%7D%3D%20astronaut%20mass%20%3D%20100%5Bkg%5D%5C%5Cm_%7Bm%7D%3D%20moon%27s%20mass%20%3D%207.36%2A10%5E%7B22%7D%5Bkg%5D)
When we match these equations the masses cancel out as the universal gravitational constant
![G*\frac{m_{e} *m_{a} }{r_{e}^{2} } = G*\frac{m_{m} *m_{a} }{r_{m}^{2} }\\\frac{m_{e} }{r_{e}^{2} } = \frac{m_{m} }{r_{m}^{2} }](https://tex.z-dn.net/?f=G%2A%5Cfrac%7Bm_%7Be%7D%20%2Am_%7Ba%7D%20%7D%7Br_%7Be%7D%5E%7B2%7D%20%20%7D%20%3D%20G%2A%5Cfrac%7Bm_%7Bm%7D%20%2Am_%7Ba%7D%20%7D%7Br_%7Bm%7D%5E%7B2%7D%20%20%7D%5C%5C%5Cfrac%7Bm_%7Be%7D%20%7D%7Br_%7Be%7D%5E%7B2%7D%20%20%7D%20%3D%20%5Cfrac%7Bm_%7Bm%7D%20%7D%7Br_%7Bm%7D%5E%7B2%7D%20%20%7D)
To solve this equation we have to replace the first equation of related with the distances.
![\frac{m_{e} }{r_{e}^{2} } = \frac{m_{m} }{r_{m}^{2} } \\\frac{5.98*10^{24} }{(3.84*10^{8}-r_{m} )^{2} } = \frac{7.36*10^{22} }{r_{m}^{2} }\\81.25*r_{m}^{2}=r_{m}^{2}-768*10^{6}* r_{m}+1.47*10^{17} \\80.25*r_{m}^{2}+768*10^{6}* r_{m}-1.47*10^{17} =0](https://tex.z-dn.net/?f=%5Cfrac%7Bm_%7Be%7D%20%7D%7Br_%7Be%7D%5E%7B2%7D%20%20%7D%20%3D%20%5Cfrac%7Bm_%7Bm%7D%20%7D%7Br_%7Bm%7D%5E%7B2%7D%20%7D%20%5C%5C%5Cfrac%7B5.98%2A10%5E%7B24%7D%20%7D%7B%283.84%2A10%5E%7B8%7D-r_%7Bm%7D%20%20%29%5E%7B2%7D%20%20%7D%20%3D%20%5Cfrac%7B7.36%2A10%5E%7B22%7D%20%20%7D%7Br_%7Bm%7D%5E%7B2%7D%20%7D%5C%5C81.25%2Ar_%7Bm%7D%5E%7B2%7D%3Dr_%7Bm%7D%5E%7B2%7D-768%2A10%5E%7B6%7D%2A%20r_%7Bm%7D%2B1.47%2A10%5E%7B17%7D%20%20%5C%5C80.25%2Ar_%7Bm%7D%5E%7B2%7D%2B768%2A10%5E%7B6%7D%2A%20r_%7Bm%7D-1.47%2A10%5E%7B17%7D%20%3D0)
Now, we have a second-degree equation, the only way to solve it is by using the formula of the quadratic equation.
![r_{m1,2}=\frac{-b+- \sqrt{b^{2}-4*a*c } }{2*a}\\ where:\\a=80.25\\b=768*10^{6} \\c = -1.47*10^{17} \\replacing:\\r_{m1,2}=\frac{-768*10^{6}+- \sqrt{(768*10^{6})^{2}-4*80.25*(-1.47*10^{17}) } }{2*80.25}\\\\r_{m1}= 38280860.6[m] \\r_{m2}=-2.97*10^{17} [m]](https://tex.z-dn.net/?f=r_%7Bm1%2C2%7D%3D%5Cfrac%7B-b%2B-%20%5Csqrt%7Bb%5E%7B2%7D-4%2Aa%2Ac%20%7D%20%20%7D%7B2%2Aa%7D%5C%5C%20%20where%3A%5C%5Ca%3D80.25%5C%5Cb%3D768%2A10%5E%7B6%7D%20%5C%5Cc%20%3D%20-1.47%2A10%5E%7B17%7D%20%5C%5Creplacing%3A%5C%5Cr_%7Bm1%2C2%7D%3D%5Cfrac%7B-768%2A10%5E%7B6%7D%2B-%20%5Csqrt%7B%28768%2A10%5E%7B6%7D%29%5E%7B2%7D-4%2A80.25%2A%28-1.47%2A10%5E%7B17%7D%29%20%7D%20%20%7D%7B2%2A80.25%7D%5C%5C%5C%5Cr_%7Bm1%7D%3D%2038280860.6%5Bm%5D%20%5C%5Cr_%7Bm2%7D%3D-2.97%2A10%5E%7B17%7D%20%5Bm%5D)
We work with positive value
rm = 38280860.6[m] = 38280.86[km]
<u>Second part</u>
<u />
The distance between the Earth and this point is calculated as follows:
re = 3.84 108 - 38280860.6 = 345719139.4[m]
Now the acceleration can be found as follows:
![a = G*\frac{m_{e} }{r_{e} ^{2} } \\a = 6.67*10^{11} *\frac{5.98*10^{24} }{(345.72*10^{6})^{2} } \\a=3.33*10^{19} [m/s^2]](https://tex.z-dn.net/?f=a%20%3D%20G%2A%5Cfrac%7Bm_%7Be%7D%20%7D%7Br_%7Be%7D%20%5E%7B2%7D%20%7D%20%5C%5Ca%20%3D%206.67%2A10%5E%7B11%7D%20%2A%5Cfrac%7B5.98%2A10%5E%7B24%7D%20%7D%7B%28345.72%2A10%5E%7B6%7D%29%5E%7B2%7D%20%20%7D%20%5C%5Ca%3D3.33%2A10%5E%7B19%7D%20%5Bm%2Fs%5E2%5D)