How much work is done when a very large force is applied to an object but doe what is the work done on a 34-n weight if it is lifted up 1 km

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 ?

An initially unpolarized light if intensity 500 w/m^2 passes through four polarizers. the transmission axis between adjacent polarizers is 45∘. what percentage of the initial intensity is transmitted by the system?

The magnetic field inside a superconducting solenoid is 4.50 t. the solenoid has an inner diameter of 6.20 cm and a length of 26.0 cm. determine (a) the magnetic energy density in the field and (b) the energy stored in the magnetic field within the solenoid.