Which surface has more friction
A. an ice rink
B. a grassy field
C. a paved road

Explanation:

Generally, roads are meant to have very rough surfaces to allow for friction between car tyres hence the motion of vehicles.

What is a paved surface?

Paved roads are roads that are covered with a firm surface suitable for travel, like paving stones or concrete or asphalts.

Another good example of a paved road is a  small paved courtyard, covered with a hard layer of concrete/cement.

The other two examples sited in this problem are glossy materials with very low surface friction, that is their surfaces are very smooth.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

the correct choice is a .

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