What are the two most important properties of a telescope?

Why there is no inductive reactance in dc circuits

Will you chech and finish these for me, because i am stumped with them.

Aturntable a is built into a stage for use in a theatrical production. it is observed during a rehearsal that a trunk b starts to slide on the turntable 10 s after the turntable begins to rotate. knowing that the trunk undergoes a constant tangential acceleration of 0.31 m/s2, determine the coefficient of static friction between the trunk and the turntable.