Answer:
They create electricity from the sun's rays
Explanation:
By the use of "solar cells" or "solar panel", you can trap solar energy in silicon/germanium rods, then you can convert in into electricity too. Solar powered panels convert the sun's rays into electricity by exciting electrons in silicon cells using the photons of light from the sun. This electricity can then be used to supply renewable energy to your home or business.
Well at the fourth half-life it would be 6.25% so if you continue calculating the answer would be B.
Answer:
171.5 N
Explanation:
The gravitational force on an object due to the Earth is given by

where
m is the mass of the object
g is the acceleration due to gravity
The acceleration due to gravity at a certain height h above the Earth is given by

where:
G is the gravitational constant
is the Earth's mass
is the Earth's radius
Here,

So the acceleration due to gravity is

We know that the mass of the object is
m = 70 kg
So, the gravitational force on it is

The acceleration due to gravity of Mars is 
<u>Explanation:</u>
As per universal law of gravity, the gravitational force is directly proportional to the product of masses and inversely proportional to the square of the distance between them. But in the present case, the gravity need to be determined between Mars and the object on Mars. Since the mass of Mars is greater than the mass of any object. Thus,

Here, G is the gravitational constant, R is the radius of Mars and M, m is the mass of Mars and the object respectively..
Also, according to Newton’s second law of motion, the acceleration of any object will be equal to the ratio of force exerted on it to the mass of the object.
So in order to determine the acceleration due to gravity of Mars, divide the gravitational force of Mars by mass of object on the surface of Mars.



