<h3><u>Answer;</u></h3>
electric potential
<h3><u>Explanation;</u></h3>
Electric potential is the electric potential energy per unit charge.
Mathematically; V =PE/q
Where; PE is the electric potential energy, V is the electric potential and q is the charge.
Electric potential is more commonly known as voltage. If you know the potential at a point, and you then place a charge at that point, the potential energy associated with that charge in that potential is simply the charge multiplied by the potential.
It's not so much a "contradiction" as an approximation. Newton's law of gravitation is an inverse square law whose range is large. It keeps people on the ground, and it keeps satellites in orbit and that's some thousands of km. The force on someone on the ground - their weight - is probably a lot larger than the centripetal force keeping a satellite in orbit (though I've not actually done a calculation to totally verify this). The distance a falling body - a coin, say - travels is very small, and over such a small distance gravity is assumed/approximated to be constant.
-- During the time the ball is flying from the high roof to the low roof,
it's going to fall (100-25) = 75 meters.
How long does it take an object dropped from rest to fall 75 meters ?
Distance = (1/2) · (gravity) · (time)²
75 m = (4.9 m/s²) · (time)²
Time² = (75 m) / (4.9 m/s²)
Time² = 15.31 sec²
Time = √(15.31 sec²) = 3.91 seconds
So the ball has to cover the horizontal distance of 20 meters
in 3.91 seconds.
Distance = (speed) · (time)
20 m = (speed) · (3.91 sec)
Speed = (20 m) / (3.91 sec)
Speed = 5.11 m/s
If you are in this kind of geographical scenery, you must be on a surfing beach in California. The Californian coastline is characterized by a numerous number of beaches that are mainly sandy and features major rivers such as the Sacramento River and the Colorado River.