What are contact force and non contact force give example

Explanation:

Force is push or pull on a body.

Contact force is a force that requires contact. It acts between two body that touches on another.

Examples are pushing a car, ringing a bell, kicking a ball.

Non contact forces are forces applied to another object without contact. The action of this force is usually through a targeted force field.

Examples are magnetic force, gravitational force

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:

need to see circuit to get time constant