When we carry an object across the room, without lifting it or setting
it down, we do no physical work on it.
true
false
More work is needed to carry a heavy suitcase slowly up a flight of stairs
than to carry the suitcase quickly up the same flight of stairs.
true
false
The amount of potential energy possessed by an elevated object is
equal to
the distance it is lifted,
the force needed to lift it,
the work done in lifting it, or
the value of the acceleration of gravity.
Ralph asked me a question about today's reading assignment. According
to the reading assignment, a car coasting from rest
down two hills, one steeper than
the other, would arrive at the bottom of each hill with the same speed, as
long as the two hills have the same vertical height. (Of course, this is
true only if we neglect friction and air resistance.) Ralph wondered how
this could be possible, since the acceleration of the car down the steep
hill is much greater than down the other hill.