Answer:
Rolling friction is much smaller than sliding friction because Rolling friction is considerably less than sliding friction as there is no work done against the body that is rolling by the force of friction. For a body to start rolling a small amount of friction is required at the point where it rests on the other surface, else it would slide instead of roll.
Rolling Friction example: Anything with weels (cars,skateboards) or a ball rooling.
Sliding Friction example: Bicycle brakes,skinning your knee walking,writing.
Answer:
The pressure is the measure of force acting on a unit area. Density is the measure of how closely any given entity is packed, or it is the ratio of the mass of the entity to its volume. The relation between pressure and density is direct. Change in pressure will be reflected in a change in density
Answer:
Then the difference of weight between the two cars are:
Δw = 14210 - 5292 = 8918 N
Explanation:
An object's weigh due to the gravitational attraction force of the earth is:
w = mg
Where: m is the object's mass
g is the gravitational acceleration in the surface earth
g = 9.8 m/s2
The the ultralight car's weight is:


And the Honda Accord's weight is:


Then the difference of weight between the two cars are:
Δw = 14210 - 5292 = 8918 N
The maximum velocity in a banked road, ignoring friction, is given by;
v = Sqrt (Rg tan ∅), where R = Radius of the curved road = 2*1000/2 = 1000 m, g = gravitational acceleration = 9.81 m/s^2, ∅ = Angle of bank.
Substituting;
30 m/s = Sqrt (1000*9.81*tan∅)
30^2 = 1000*9.81*tan∅
tan ∅ = (30^2)/(1000*9.81) = 0.0917
∅ = tan^-1(0.0917) = 5.24°
Therefore, the road has been banked at 5.24°.