numerical question a single movable pulley to lift a load of 800 N applying 300 N force. calculate the efficiency of the pulley.​

An electric current is flowing through the cord below.what will happen to this current if a magnet is brought near the cord? a. the electric current will stop flowing. b. it will exert a force on the voltage. c. the resistance of the wire will decrease. d. it will exert a force on the electric current.

A20 cm long spring is attached to a wall. the spring stretches to a length of 22 cm when you pull on it with a force of 100 n. what is the spring constant

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.