An electric winch with an efficiency of 70% is used to lift a crate of mass 80 kg vertically upwards at a constant speed of 1.25 m s-1.
Calculate the electrical input power of the winch.
(Take g=9.8 m s−2g = 9.8\text{ m s}^{-2}g=9.8 m s−2.)
0.69 kW0.69\text{ kW}0.69 kW
0.98 kW0.98\text{ kW}0.98 kW
1.4 kW1.4\text{ kW}1.4 kW
2.0 kW2.0\text{ kW}2.0 kW
Practise OCR GCSE Physics Power and efficiency with exam-style questions for Foundation and Higher tier. 46 questions, matched to the OCR GCSE Physics (J249) specification and written in Paper 1 and Paper 2 (Foundation Tier) or Paper 3 and Paper 4 (Higher Tier) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.