Question

The place where potential energy is not zero
a) At height equal to double the radius of the earth
b) At infinity
c) At a height equal to half the radius of the earth
d) At a depth equal to 1/3 radius of the earth​

Answer 1

Answer:

b) At infinity

Explanation:

Let's get kinetic energy and potential energy. Kinetic energy shows motion and potential energy shows motion resistance, since we have the rule to save all the energy in one piece lets get heat energy and see how it works: When the skater is preparing to start he is cool and his potential energy is at the maximum possible, once he drops to start going down the ramp then kinetic energy rises up and the heat energy rises up too, but heat energy rises faster when kinetic energy is bigger and rises slower when kinetic energy is smaller. This causes the skater to slow down because of frictional force caused by the rise of heat and kinetic energy. The more the heat rises, the more the kinetic and potential energy lower, as we know that kinetic energy is motion then we choose answer b) At infinity because as first principe of mechanic say: If there is no force on a body then it doesn't accelerate. Hope I helped! ;P