If a 25.5 kg child climbs 2 steps of 20 cm each, the work performed is

The magnitude of the poynting vector of a planar electromagnetic wave has an average value of 0.939 w/m2 . the wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles. how much total electromagnetic energy falls on the area during 1.0 minute

Asystem containing an ideal gas at a constant pressure of 1.22×10^5 pa gains 2140 j of heat. during the process, the internal energy of the system increases by 2320 j. what is the change in volume of the gas?

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity