Answer: a.) Roughness of the surfaces in contact with each other .
Higher the roughness of surfaces in contact with each other, greater is the friction between bodies. Force of friction will be less between smooth surfaces.
b.) Weight of the sliding/rolling body: greater the weight of the moving body on the surface, more is the force of friction on the body by the surface.
I hope this helps
Answer:
A)t=<u>1.375s</u>
B)t=11s
Explanation:
for this problem we will assume that the east is positive while the west is negative, what we must do is find the relative speed between the wave and the powerboat, and then with the distance find the time for each case
ecuations
V=Vw-Vp (1)
V= relative speed
Vw= speed of wave
Vp=Speesd
t=X/V(2)
t=time
x=distance=44m
A) the powerboat moves to west
V=18-(-14)=32m/s
t=44/32=<u>1.375s</u>
B)the powerboat moves to east
V=18-14=4
t=44/4=<u>11s</u>
Apparently, the question is looking for A. electric potential energy;
but I don't think that's quite right. Electric potential difference is expressed in Joules / Coulomb which is the work to move a charge between 2 points
Example: If the electric field between, say, between 2 capacitor plates is
E = 100 Newtons / Coulomb then the work done in moving a unit of charge from the negative plate to the positive plate separted by 1 cm is
V = E * d = 100 Newtons / Coulomb * .01 meters = 1 Newton-meter / Coulomb
= 1 Joule / Coulomb which is the electric potential or potential difference
(The definition of electric potential between points is "the work moving a unit positive test charge from one point to the other")
Now in our above example where V = 1 Joule / Coulomb
if we move 10 Coulombs from the negative plate to the positive plate
W = V Q = 1 Joule / Coulomb * 10 Coulombs = 10 Joules
where work done has the correct units of Joules.
Your textbook should help clarify this.
Circulatory system
The tunica adventitia, the outermost layer, is the strongest of the three layers. It is composed of collagenous and elastic fibres. (Collagen is a connective-tissue protein.) The tunica adventitia provides a limiting barrier, protecting the vessel from overexpansion.
