Question

mechanical energy is defined as:*
the energy required to move a 1 kg object 1 m
the sum of kinetic and gravitational potential energy
the change in kinetic energy of an object
the change in gravitational potential energy of an object
the difference between kinetic and gravitational potential energy

Explanation:

Mechanical energy is the sum of kinetic energy (energy of motion) and potential energy (stored energy, in this case gravitational potential energy). The first option describes work (force - distance, \(W = F\times d\), and \(F=ma\), so \(W = ma\times d\), for \(m = 1\space kg\), \(a = g\approx9.8\space m/s^{2}\), \(d = 1\space m\), \(W\approx9.8\space J\), not mechanical energy). The third option is the change in kinetic energy (related to work - energy theorem \(W=\Delta K\)). The fourth option is the change in gravitational potential energy (\(\Delta U =mg\Delta h\)). The fifth option (difference) is incorrect as mechanical energy is a sum.

Answer:

The sum of kinetic and gravitational potential energy