When a board with a box on it is slowly tilted to a larger and larger angle, common experience shows that the box will at some point "break loose" and start to accelerate down the board. the box begins to slide once the component of its weight parallel to the board, w||, equals the maximum force of static friction. which of the following is the most general explanation for why the box accelerates down the board after it begins to slide (rather than sliding with constant speed)?

friction and inertia is acting upon the box

The coefficient of kinetic friction is less than the coefficient of static friction.

Explanation:

At the point when the box finally does "break loose," the component of the box's weight that is parallel to the board,  w|| , is equal to  μsn  (the maximum force of static friction). For the box to then accelerate, there must be a nonzero net force acting on the box parallel to the board. In other words,  w||  must be greater than the force of kinetic friction,  fk=μkn . Therefore the force of kinetic friction,  μkn  , must be less than the force of static friction,  μsn , which implies  μk<μs , as expected.

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: