Answer:
c. 70 Ω
Explanation:
The R and R resistors are in parallel. The 2R and 2R resistors are in parallel. The 4R and 4R resistors are in parallel. Each parallel combination is in series with each other. Therefore, the equivalent resistance is:
Req = 1/(1/R + 1/R) + 1/(1/2R + 1/2R) + 1/(1/4R + 1/4R)
Req = R/2 + 2R/2 + 4R/2
Req = 3.5R
Req = 70Ω
The Earth's radius is 6371 km. So that's our distance from the center when we're on the surface.
The Shuttle astronaut's distance from the center, when s/he's in orbit, is 330 km greater ... that's 6701 km.
The force of gravity is inversely proportional to the distance between the center of the Earth and the center of the astronaut. So, in orbit, it's
(6371/6701)^2 = 90.4 %
of its value on the surface.
A light-year is how astronomers measure distance in space.
-Light can travel 300,000 kilometres in one seconds!
Light year is the distance that light travel can travel in one year.
-Light can also travel 9,00,000,000,000 kilometers.
-One light is about 10 trillion km.
-Almost 300 years ago ,a Danish scientist named olaus roemer,was the fist man to estimate the distance light travels in a year -and using that he figure out the approximate speed of light!
E= electric field
E=F/q= force per unit charge
q= charge
