A120 kg santa claus slides down a 9 m chimney. he drops from his sleigh 2 m above the top of the chimney. it’s a tight fit, but he slides the whole way. he just comes to rest as he reaches the hearth. what is the force of friction on santa from the chimney? a) 750 nb) 2000 nc) 2500 nd) 3200 ne) 1500 n

E) 1500 N

Explanation:

The total height from which Santa has fallen down is

h = 9 m + 2 m = 11 m

So its gravitational potential energy at the beginning was

While sliding down, Santa has lost all its gravitational potential energy: this energy has been converted into thermal energy due to the presence of the friction. So, the work done by friction is exactly equal to the initial potential energy of Santa:

The work done by friction is

where

F is the force of friction

d = 9 m is the length of the chimney (the distance through which the frictional force acts)

Solving the equation for F, we find

So the closest option is

E) 1500 N

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: