A crane lifts 1 tonne of concrete through a height of 25 m. How much work does it do? (1 kg has a weight of 9.81 N.) A bodybuilder lifts a 350 N set of weights from ground level to a position over his head, a vertical distance of 2.15 m. How much work (in J) does the bodybuilder do? Assume the weights are moved at a constant speed. The changes in specific internal energy across the compressor is 82 KJ/kg and the heat loss by cooling is 24 KJ/kg. Neglecting changes in kinetic and potential energies, find the work in KW. 32. Calculate the change of entropy per kg of air when heated from 300 K to 600 K while the pressure drops from 400 Kpa to 300 KPa. When the bottom 4.00-kg block is pulled to the left by the constant force P →, P →, the top 2.00-kg block slides across it to the right. Find the magnitude of the force necessary to move the blocks at constant speed. Assume that the coefficient of kinetic friction between all surfaces is 0.400. or W = 2656.5 W = 2656.5 kg-m 2 2 /s 2 2. I'll leave the potential energy approach as an exercise. You could equivalently (for all physical aspects to consider) cut off the lower 11 meters and put them on top of the building. That way you lift 11 63 11 63 of the total mass by 63 − 11 2 63 − 11 2. The work done by the force of gravity, on an object near the surface of Earth, depends only on the weight of the object and the difference in height through which it moved. 25. (a) Calculate the work done on a 1500-kg elevator car by its cable to lift it 40.0 m at constant speed, assuming friction averages 100 N. (b) What is the work done Work Done by Force of Gravity. Question. A man weighing 80 kg climbs a staircase carrying a 20 kg load. The staircase has 40 steps, A 50 k g man with 20 k g load on his head climbs up 20 steps of 0.25 m height each. The minimum work done by the man on the block during climbing is. TI01A.

find the work done when a 25 kg weight