Answer:
891 excess electrons must be present on each sphere
Explanation:
One Charge = q1 = q
Force = F = 4.57*10^-21 N
Other charge = q2 =q
Distance = r = 20 cm = 0.2 m
permittivity of free space = eo =8.854×10−12 C^2/ (N.m^2)
Using Coulomb's law,
F=[1/4pieo]q1q2/r^2
F = [1/4pieo]q^2 / r^2
q^2 =F [4pieo]r^2
q = r*sq rt F[4pieo]
q=0.2* sq rt[ 4.57 x 10^-21]*[4*3.1416*8.854*10^-12]
q = 1.42614*10^ -16 C
number of electrons = n = q/e=1.42614*10^ -16 /1.6*10^-19
n =891
891 excess electrons must be present on each sphere
In order to balance the stick on the pivot, the total "moments" must be equal on both sides. A "moment" is (a weight) x (its distance from the center).
for the 5N weight: Moment = (5N) x (3 cm) = 15 N-cm
for the 12N weight: Moment = (12N) x (5 cm) = 60 N-cm
Sum of the moments trying to pull the stick down on that side = 75 N-cm
Whatever we hang on the other side has to provide a moment of 75 N-cm in the other direction. We have a 25N weight. Where should we hang it ?
(25N) x (distance from the pivot) = 75 N-cm
Distance from the pivot = (75 N-cm) / (25 N)
<em>Distance from the pivot = 3 cm </em>
Answer:
its supposed to be (a) 1W
The answer is the last one
A car slowing down from 50 miles per hour 20 miles per hour
