Home › AP Physics 1 › Physics › Work, Energy, and Energy Resources › Suppose the same 65.0-kg player instead slides w…
Suppose the same 65.0-kg player instead slides with the same 6.00 m/s initial speed up a 5.00 degree incline, still against a 450 N friction force. Compared with sliding the 2.60 m distance found on level ground, does he slide farther or a shorter distance up the incline, and why?
AFarther, because gravity now helps maintain his kinetic energy
BThe same distance, because friction alone determines the stopping distance
CA shorter distance, because gravity now also removes kinetic energy as he gains height
DIt cannot be determined without knowing the coefficient of friction
Answer & Solution
Correct answer: C. A shorter distance, because gravity now also removes kinetic energy as he gains height
1. Going uphill, both friction and the gravitational potential energy gain work against the player's initial kinetic energy, since one half m vi squared equals fd plus mgd sin(theta).
2. Because two effects now remove kinetic energy instead of just friction alone, the stopping distance d comes out smaller than the 2.60 m found on level ground.
3. The player therefore slides a shorter distance up the incline, not farther and not the same distance as on level ground.
4. The problem gives the friction force directly as 450 N, so the coefficient of friction is not needed to determine that the distance decreases.
_Source: OpenStax College Physics (CC BY 4.0), Ch 7 "Work, Energy, and Energy Resources", section 7.5 Nonconservative Forces_
Related questions
China's energy mix differs sharply from that of most Western countries. What fuel dominateOnly 10% of United States electricity is generated by renewable resources. Which renewableMost countries rely heavily on nonrenewable resources for electricity, but some meet a larRenewable energy sources include water, wind, solar, and biomass, since these cannot be usThe United States has 4.5% of the world's population. According to world energy use figureAmong the principal energy resources used worldwide, which single fuel supplies about 40% A surprisingly large share of all the energy the human body consumes goes toward a purposeUseful work, as defined for a person's activities, includes climbing stairs or acceleratin