When a mass rests on a surface, the surface "pushes up" on the object with a force that is equal in
magnitude to the gravitational force exerted by the object on the surface. this is sometimes called the
"normal force." suppose that a 30 kg basset hound rests on a couch. what is the magnitude of the normal
force that the couch exerts on the dog? hint: the acceleration due to gravity on the earth's surface is 9.8
m/s2 and 1 newton = 1 kg m/s2

An object has a weight of 500 on earth what is the mass of this object

What do the atoms of elements in the same group have in common? a. they have the same atomic numbers. b. they have the same average atomic masses. c. they have the same number of electron shells. d. they have the same number of electrons in their outermost shells.

An air standard cycle with variable specific heats is executed in a closed system and is composed of the following four processes. 1-2 isentropic compression 100 kpa and 22°c to 600 kpa 2-3 v=constant heat addition to 1500 k 3-4 isentropic expansion to 100 kpa 4-1 p=constant heat rejection to initial state (a) show the cycle on p-v and t-s s (b) calculate the net work output per unit mass (409 kj/kg) (c) determine the thermal efficiency (47.9%)