Asound system is being set up in a gazebo in a park. it needs to produce music so that everyone can hear it. how much power would the speakers need to produce in order for the intensity at 5 meters away to be 1 x 10^-8 w/m^2? (assume the shape of the propagation of the sound wave is a hemisphere)

1.87 x 10^-7 w
1.57 x 10^-6 w
1.14 x 10^-6 w
2.46 x 10^-7 w

Aman throws a football straight into the air. as it rises, it slows down. which type of energy is the football gaining?

Ametal ring 4.20 cm in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. these magnets produce an initial uniform field of 1.12 t between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.240 t/s . (a) what is the magnitude of the electric field induced in the ring? (b) in which direction (clockwise or counterclockwise) does the current flow as viewed by someone on the south pole of the magnet?

Could we see a galaxy that is 20 billion light-years away?