Kinetic energy is never negative, but potential energy can be.
Potential energy depends on height above some reference level,
and you can pick any level you want as the reference. So, if the
object is below the reference level you pick, then its potential
energy relative to your reference level is negative.
What that means is: You have to lift it / do work on it / give it more
energy than it has now ... in order to move it to the reference level.
(That's exactly the situation with electrons bound to an atom. Their
energy is considered negative, because we have to do work and
give them more energy to rip them away from the atom.)
_____________________________________
Regarding the other choices:
-- Kinetic energy is scalar ... Yes. So is potential energy.
-- Kinetic energy increases with height ...
No. It doesn't, but potential energy does.
-- Kinetic energy depends on position ...
No. It doesn't, but potential energy does.
Answer:
3 j
Explanation:
12.0 kilo / 4.00 meters = 3 j
Moons gravity is about 1/6 as powerful as it is on Earth, so about 20 pounds.
Incomplete question. Missing part:
"it took him 10 seconds to move the couch. What was his power?"
Answer:
50 W
Explanation:
The power developed is given by:
where
W is the work done
t is the time taken
In this problem,
W = 500 J
t = 10.0 s
Substituting into the equation, we find
C) The weight of the object on planet A will be less than the weight of the object on planet B.
This happened because: when gravitational pull of a planet is weak, an object will weigh less as a result of less gravity forcing it down to the ground.
