A firecracker explodes at the origin of an inertial reference frame. Then, 2.0 ms later, a second firecracker explodes 300 m away. Astronauts in a passing rocket measure the distance between the explosions to be 200 m. According to the astronauts, how much time elapses between the two explosions?

Goals • To understand current and how charges move in a conductor • To understand resistivity and conductivity • To calculate the resistance of a conductor • To learn how an emf causes current in a circuit • To calculate energy and power in circuits Introduction • Electric currents flow through light bulbs. • Electric circuits contain charges in motion. • Circuits...