Answer:

Explanation:
The volume charge density is defined by ρ =
(Equation A), where Q is the charge and V, the volume.
The units in the S.I. are
, so we have to express the radius in meters:
inner radius = 
outer radius = 
Now, we know that the volume of the sphere is calculated by the formula:
, and as we have an spherical shell, the volume is calculated by the difference between the outher and inner spheres:
V =
, where
is the outer radius and
is the inner radius.
Replacing the volume formula in the Equation A:
ρ = 
ρ = 
Replacing the values of the outer and inner radius whe have:
ρ = 
ρ = 
1) in the opposite direction always
2) drag force is the force that acts in the opposite direction of the applied force (air resistance if a drag force for example)
3) frictions forces between the sole and the ground as the owner walks
4) chalk would glide very easily, so a creaking sound could never be produced, but also one could not write anything on the board!
5) I apologize for my lack of familiarity with the kind of sport but the probable answer is to raise the friction of their hands in order to decrease slipping and get a tighter, more firm grip
<h3><u>Answer;</u></h3>
B. 16.2 m/s
<h3><u>Explanation</u>;</h3>
Using the equation;
v = u + at; where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken;
u = 21 m/s, a= -2.4 m/s^2 and t = 2 seconds
Therefore;
v = 21 + ((-2.4) × 2)
= 21 - 4.8
<u> = 16.2 m/s</u>
Answer: 9.98 *10^-19 J
Explanation: In order to explain this probelm we have to consider the balance enegy for photoelectric effect.
h*f-W=Ek where h is the Planck constant and W the work function and Ek the kinetic energy. f is the frequency of light.
W=h*f-Ek=6.62*10^-34*2.4*10^15-5.9*10^-19=9.98*10^-19J
Answer:
Finding the Force of Friction Without an Experiment
1.The following equation tells you the strength of the frictional force (with the static friction coefficient): F = μ s t a t i c N F=\mu_{static} N F=μstaticN.
2.If your surface is flat and parallel to the ground, you can use: ...
3.If it isn't, the normal force is weaker.