Answer:
D) 8.0 s.
Explanation:
(The following exercise is written in Spanish. Hence, explanations will be held in such language.)
La energía requerida para elevar el ascensor es el cambio en la energía potencial gravitacional, cuya magnitud es:
![\Delta E_{g} = (200\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (20\,m)](https://tex.z-dn.net/?f=%5CDelta%20E_%7Bg%7D%20%3D%20%28200%5C%2Ckg%29%5Ccdot%20%5Cleft%289.807%5C%2C%5Cfrac%7Bm%7D%7Bs%5E%7B2%7D%7D%20%5Cright%29%5Ccdot%20%2820%5C%2Cm%29)
![\Delta E_{g} = 39228\,J](https://tex.z-dn.net/?f=%5CDelta%20E_%7Bg%7D%20%3D%2039228%5C%2CJ)
Ahora, la potencia media es el resultado anterior dividido por el tiempo. Se despeja el tiempo de la ecuación:
![\Delta t = \frac{\Delta E_{g}}{\dot W}](https://tex.z-dn.net/?f=%5CDelta%20t%20%3D%20%5Cfrac%7B%5CDelta%20E_%7Bg%7D%7D%7B%5Cdot%20W%7D)
![\Delta t = \frac{39228\,J}{5000\,W}](https://tex.z-dn.net/?f=%5CDelta%20t%20%3D%20%5Cfrac%7B39228%5C%2CJ%7D%7B5000%5C%2CW%7D)
![\Delta t = 7.846\,s](https://tex.z-dn.net/?f=%5CDelta%20t%20%3D%207.846%5C%2Cs)
La opción más aproximada es D.
Answer
Given,
Periscope uses 45-45-90 prisms with total internal reflection adjacent to 45°.
refractive index of water, n_a = 1.33
refractive index of glass, n_g = 1.52
When the light enters the water, water will act as a lens and when we see the object from the periscope the object shown is farther than the usual distance.
First let us calculate for the angle of inclination using
the sin function,
sin θ = 1 m / 4 m
θ = 14.48°
Then we calculate the work done by the movers using the
formula:
W = Fnet * d
So we must calculate for the value of Fnet first. Fnet is
force due to weight minus the frictional force.
Fnet = m g sinθ – μ m g cosθ
Fnet = 1,500 sin14.48 – 0.2 * 1,500 * cos14.48
Fnet = 84.526 N
So the work exerted is equal to:
W = 84.526 N * 4 m
<span>W = 338.10 J</span>
The growth of plantesimals from smaller solid particles that collided and stuck together
Orbital velocity is the velocity of celestial body/satellite revolving around another celestial body in circular orbit.
V
![ _{o}](https://tex.z-dn.net/?f=%20%0A_%7Bo%7D%20)
=
![\sqrt{ \frac{GM}{R} }](https://tex.z-dn.net/?f=%20%5Csqrt%7B%20%5Cfrac%7BGM%7D%7BR%7D%20%7D%20)
---(i)
Escape velocity is the minimum initial velocity a body should be given to escape it from gravitational field.
V
![_{escape}](https://tex.z-dn.net/?f=%20_%7Bescape%7D%20)
=
![\sqrt{ \frac{2GM}{R} }](https://tex.z-dn.net/?f=%20%5Csqrt%7B%20%5Cfrac%7B2GM%7D%7BR%7D%20%7D%20)
---- (ii)
Divide (i) and (ii)
![\frac{V_{o} }{V_{escape} } = \frac{1}{ \sqrt{2} }](https://tex.z-dn.net/?f=%20%5Cfrac%7BV_%7Bo%7D%20%7D%7BV_%7Bescape%7D%20%7D%20%3D%20%20%5Cfrac%7B1%7D%7B%20%5Csqrt%7B2%7D%20%7D%20)
R = radius of circular orbit, M = mass of the celestial body about which satellite/body is performing circular motion. G = Universal gravitational constant