The chart shows data for four heat engines. Heat Engine
w
х
Y
Z
Th (K)
620
840
900
500
T. (K)
120
100
300
25
Which lists the engines from most efficient to least efficient?
OY, X, W, Z
OZ, W, X, Y
O Z, X, W, Y
OY, W, X, Z

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.

What kind of simple machine is a catapult?