A particle moves from A to B under conservative and non-conservative forces. Which statements are correct?

Select all that apply

• Option A

  Δ(K+U) = $W_nc$

• Option B

  If $W_nc$ = 0, mechanical energy is conserved

• Option C

  If friction does negative work, mechanical energy generally decreases

• Option D

  Mechanical energy can increase due to positive work by an external non-conservative force