Answer:
:Electric charge is a basic property of electrons, protons and other subatomic particles. Electrons are negatively charged while protons are positively charged. ... Things that have the same charge push each other away (they repel each other). This is called the Law of Charges.
Explanation:
Answer:
The ratio of the time he is above ymax /2 to the time it takes him to go from the floor to that height = 0.707
Explanation:
The mathematical derivation and steps is as shown in the attached file.
NB: The diagram of the pulley system is not shown but the information provided is sufficient to answer the question
Answer:
Power = 2702.56 W
Explanation:
Let the power consumed be P
Energy expended = E = mgh
height, h = 5 m
E = 80 * 9.8 * 5
E = 3920 J

To calculate the time, t
From F = ma
F = 900 N
900 = 80 a
a = 900/80
a = 11.25 m/s²
From the equation of motion, 
The drill head starts from rest, u = 0 m/s

Power, P = E/t
P = 3920/0.0.943
P = 4157.79 W
But Efficiency, E = 0.65
P = 0.65 * 4157.79
Power = 2702.56 W
Answer: For me personally i have a Biblical faith and first of all there is evidence that looks convincing that the big bang made the universe, but man wants answers and God in the Bible says he created the universe for us it is hard to believe it but i have faith.
Answer:
f = 19,877 cm and P = 5D
Explanation:
This is a lens focal length exercise, which must be solved with the optical constructor equation
1 / f = 1 / p + 1 / q
where f is the focal length, p is the distance to the object and q is the distance to the image.
In this case the object is placed p = 25 cm from the eye, to be able to see it clearly the image must be at q = 97 cm from the eye
let's calculate
1 / f = 1/97 + 1/25
1 / f = 0.05
f = 19,877 cm
the power of a lens is defined by the inverse of the focal length in meters
P = 1 / f
P = 1 / 19,877 10-2
P = 5D