I). mechanical energy is the sum of potential energy and kinetic energy in an object that is used to do work.
ii). the principle of the conservation of mechanical energy states that the mechanical energy in a system remains constant as long as the only forces acting are conservative.
iii). frictional force is a non-conservative force.
which of the following statement below is false?
a) for the motion of a cart on a frictionless incline plane, the magnitude of the change in kinetic energy equals the magnitude of the change in gravitational potential energy
b) for the motion of a cart on an incline plane having a coefficient of kinetic friction of 0.5, the magnitude of the change in kinetic energy equals the magnitude of the change in gravitational potential energy
c) assuming a constant gravitational potential energy for a cart, the work-done by a net force on the cart equals the change in its kinetic energy
d) in an ideal free fall, the magnitude of the change in gravitational potential energy equals the magnitude of the change in gravitational potential energy