An electric hoist is used at a construction site to lift a concrete block.
The hoist lifts a block of weight 800 N800\text{ N}800 N through a vertical distance of 4.5 m4.5\text{ m}4.5 m in 6.0 s6.0\text{ s}6.0 s.
Calculate the useful work done in lifting the block.
An electric motor drives the hoist mechanism. The current in the motor is 12 A12\text{ A}12 A when it is connected to a 100 V100\text{ V}100 V power supply.
Calculate: (i) the electrical energy supplied to the motor in 6.0 s6.0\text{ s}6.0 s, (ii) the overall efficiency of the hoist in lifting the block.
Suggest two mechanisms by which energy is wasted during this operation.
229 exam-style questions on CIE IGCSE Physics 1.7.1a Energy stores and energy transfers. Each one has a worked solution and a mark scheme showing where the marks go.