Answer:
1.69 * 10^(-7) C
Explanation:
We can find this by using the formula for electric potential while making charge the subject of formula:
V = kQ/r
=> Q = (V*r)/k
Where k = Coulumbs constant
V = electric potential
Q = charge
r = distance between doorknob and charged body
From the question,
V = 6 kV = 6000 V
r = (25 + 0.3) cm = 25.3 cm = 253m
Note: Since we assume that the body is a sphere and we know that the charge in a sphere is concentrated in it's center, we add the radius of the sphere to the length of the spark (which tells us the distance between the doorknob and body) to get the distance between the doorknob and the charge.
Hence:
Q = (6000 * 0.253)/(9 * 10^9)
Q = 1.69 * 10^(-7) C
Electron has the least amount of mass!
Ice, which is the solid state of water, the liquid
Answer:
v = 7.67 m/s for L= 1m
Explanation:
Let's use the conservation of mechanical energy, at the highest point and the lowest point
Initial. Vertical ruler
Em₀ = mg h
Final. Just before touching the floor
= K = ½ I w²
Em₀ =
m g h = ½ I w²
The moment of inertia of a ruler that turns on one end is
I = 1/3 m L²
Let's replace
m g h = ½ (1/3 m L²) w²2
g h = 1/6 L² w²
They ask for the speed of the end so the height h is equal to the length of the ruler
g L = 1/6 L² w²
The linear and angular variables are related
v = w r
w = v / r
In this case the point of interest a in strangers r = L
g L = 1/6 L² v² / L²
v = √ 6 g L
Let's calculate
Assume that the length of the meter is L = 1 m
v = √ (6 9.8 1)
v = 7.67 m/s
I don’t use the metric system, so I used feet and then went back.
25 meters is about 82 feet.
So around 82 feet per minute (kinda slow LOL)
82 (feet per minute) x 90 (minutes) = 7380 feet (in 90 minutes)
7380 feet is equal to 2249.424 meters.
(I hope that helped)