a truck driver loads some oil drums into a truck by lifting them directly each drum has a mass of 100kg and the platform of the truck is at a height 100 cm above the ground(g=9.8)1.how much energy is used to lift
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Answer:
(i) Mass of the drum = 80 kg. and g = 10 m/s2 Force of gravity on drum = m g = 80 x 10 = 800 N. (ii) Force of gravity on drum = 800 N. Total distance covered = 0.8 m Work done by the driver = Force x Distance = 800 x 0.8 m = 640 J. Energy converted = m g h = 640 J. (iii) When the force needed to push a drum up the plank is 300 N which is less than the answer to part (i) because plank make an angle with the road thus making an inclined plane which decreases the force or the efforts acting on the drum to push it up into the truck. (iv) The force exerted by the engine of the truck moves the truck and this work done by the force changes into K.E. of the truck (v) When the driver has to stop at the factory gate this K.E. is converted into the work done by the resisting force to stop