Light behaves primarily as a wave when it

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

The pressure increases by 1.0 x 104 n/m^2 for every meter of depth beneath the surface of the ocean. at what depth does the volume of a pyrex (bulk modulus 2.6 x 1010n/m^2) glass cube, 9.8 x 10^−2m on an edge at the ocean's surface, decrease by 7.5 x 10−10m^3? explain the formula beyond this point: p=1.0x10^4, b=2.6x10^10, l=9.8x10^−2, delta v=7.5x10^−10. at some point l needs to be cubed. why p is divided by delta v?

An alien spaceship is 500 m above the ground and moving at a constant velocity of 150 m/s upwards. how high above the ground is the ship after 5 seconds?