The blades of a windmill sweep out a circle of area :-What is the kinetic energy of the air ?

The blades of a windmill sweep out a circle of area :- Assume that the windmill converts 25% of the wind’s energy into electrical energy, and that A = 30 m^2, v = 36 km//h and the density of air is 1.2 kg ,m^-3 . What is the electrical power produced ?

The blades of a windmill sweep out a circle of area:- If the wind flows at a velocity v perpendicular to the circle, what is the mass of the air passing through it in time t ?

What is the SI unit of kinetic energy ?

What is the relation between kinetic energy and temperature ?

The total energy of an electron in the first excited state of the hydrogen atom is about -3.4 eV. (A) What is the kinetic energy of the electron in this state? (B) What is the potential energy of the electron in this state? (C) Which of the answers above would change if the choice of the zero of potential energy is changed?

A neutron beam of energy E scatters from atoms on a surface with a spacing d=0.1nm. The first maximum of intensity in the reflected beam occurs at theta=30 . What is the kinetic energy E of the beam in eV?

The total energy of an electron in the first excited state of the hydrogen atom is about-3.4ev What is the kinetic energy of the electron in this state?

A skater of mass 50 kg moves down from A to B. The frictional forces are absent. What is the kinetic energy at B?