Answer:
Explanation:
Potential at a point near a charge = Q / 4πε₀ R
where Q is charge given , R is distance of point from the charge .
Q / 4πε₀ R = 40
Electric field E at A = -dV / dR
= .16 x 10⁻³ / 2 x 10⁻⁶
= .08 x 10³
= 80 N/C
E = Q / 4πε₀ R²
80 = Q / 4πε₀ R x R
80 = 40 / R
R = 40 / 80
= .5 m .
Measuring mass with a balance
Answer:
time is 0.42 sec
Explanation:
Given data
radius = 23 m
angular acceleration = 5.7 rad/s²
to find out
time
solution
we know that radius is constant so that
tangential acceleration At = angular acceleration × radius ............. 1
tangential acceleration = 5.7 × 23 = 131.1 m/s²
and
radial acceleration Ar = (angular velocity)² × radius ........................2
we consider angular velocity = ω
this is acting toward center
so
compare 1 and 2
At = Ar
5.7 r =ω³ r
ω = √5.7 = 2.38746 rad/s
so
ω = 5.7 t
2.387 = 5.7 t
t = 2.387 / 5.7
t = 0.4187
time is 0.42 sec
