An alternating current in a wire has a voltage of 2,800 v. it needs to be reduced 70 v. the wire makes 120 turns in the primary coil of a step- down transformation. how many turns of wire need to be in the secondary coil?

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?

The voltage applied across a given parallel-plate capacitor is doubled. how is the energy stored in the capacitor affected?