You want to build a generator to light a bulb. You have a fairly large permanent magnet, some wire, and a lightbulb. You may build it as follows. Wind the wire for about 200 turns into a coil of 15 cm radius. Tape up the coil and place it in the region between the poles of the magnet that produces a 0.10 T magnetic field. Connect a hand crank to the coil and rotate it at a rotational speed ω. What is the required rotational speed ω to generate a peak voltage of 6 V?

Awater balloon launcher uses an elastic band with a spring constant of 115 n/m to use thee launcher you stretch thee band back with a balloon n it the water balloons have a mass of 1.3 kg a) if you stretch the band by 0.8 m, what elastic force will the band exert? b) with the band stretched 0.8 m, how much elastic potential energy is stored in the spring? c) if you release the band, it pushes forward. what is the kinetic energy of the balloon when it reaches the natural length of the band? d) what is the speed of the balloon when it reaches the natural length of the band?