Under what conditions can the resultant of two vectors be determined simply by adding their magnitudes as scalars?

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 11.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.80 m/s; (b) he is then lifted at the constant speed of 4.80 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 78.0 kg rescue by the force lifting him during each stage

The law of conservation of energy states that energy cannot be created or , energy can be from one substance to another. the first blank is ' destroyed ' and for the second blank is ' transferred '

An object has a weight of 500 on earth what is the mass of this object