Work, Power and Energy
Important question answer (Chapter Revision) Q1. A man climbs a slope and another walks the same distance on a level road. Who does more work and why ? Answer: The man who walk on a level road does no work as he is walking at right angle to the direction of gravitational force. Hence the man climbs a slope is doing more work. Q2. State the CGS and SI units of work. Answer : CGS unit of work is erg or gcm2s2 S.I. unit of work is joule or kgm2s2 1 J = 107 ergs or 1 erg = 10-7 g Q3. What is horsepower ? What is its magnitude in SI unit ? Answer : Horse power is unit of power used in engineering 1 H.P = 746 w. Q4. Prove mathematically the law of conservation of energy. Answer : Law of conservation of energy : “Energy can neither be created nor destroyed. Though it can be transformed from one form to other.” At A Consider a body of mass m at A at a height h above the ground level. P.E. = mgh K.E. = 0 at rest. P.E. + K.E. = mgh + O = mgh …………….. (i) Let it fall from A ...