Astudent makes a simple pendulum by attaching a mass to the free end of a 1.50-meter length of string
suspended from the ceiling of her physics classroom. she pulls the mass up to her chin and releases it from
rest, allowing the pendulum to swing in its curved path. her classmates are surprised that the mass doesn’t
reach her chin on the return swing, even though she does not move. explain why the mass does not have
enough energy to return to its starting position and hit the girl on the chin.

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: