Answer : The static friction depends on two factors
1. Roughness of the surface
2. Force
Explanation : Friction occur when surface is not smooth.
The formula of friction is

Static friction depends on the roughness of the surface and force which is trying to push to object along the surface.
Static friction is caused by the attraction between two surfaces that are in contact. when the surface will rough and the object will heavier then the force will be larger.
Answer:
Velocity
Explanation:
"The principle is that the slope of the line on a position-time graph is equal to the velocity of the object. If the object is moving with a velocity of +4 m/s, then the slope of the line will be +4 m/s."
^^This explanation is from physicsclassroom.com
Density=mass/volume therefore volume=mass/density; 55g/11.4g/cm^3= 4.82cm^3
Power = 1800W (or 1.8KW by dividing by 1000)
Time = 3 hours
Power = energy/ time
1.8KW = energy/ 3
x3
5.4Kw/h= energy
(5.4KJ or 5400J used)
$0.15 Kw/h
$0.15 X 5.4 = 0.81
Thus, cost $0.81
Hope this helps!
PH of 4 is Acidic and its property is to turn blue litmus red