An audio amplifier, represented by the AC source and the resistor, R, delivers alternating voltages at audio frequencies to the speaker. If the source puts out an alternating voltage of 15.0 V, the resistance, R, is 8.20 Ω and the speaker is equivalent to a resistance of 10.4 Ω. Calculate the: a) rms current of the circuit.

Could someone . i have tried to solve myself but my calculation is off

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon