An Olympic weight lifter lifts 145 kg a vertical distance of 2.1 m. When he does so, 6.0 x 104 J of heat is transferred to air through perspiration. Does he gain or lose internal energy and how much?
Answer to relevant QuestionsAn ideal gas is taken through the reversible processes shown in Fig. 12.21. (a) Is the overall change in the internal energy of the gas (1) positive, (2) zero, or (3) negative? Explain. (b) In terms of state variables p ...A child’s swing (a pendulum) has only one natural frequency, f1, yet it can be driven or pushed smoothly at frequencies of f1/2, f1/3, and 2f1. How is this possible? (a) At what position is the speed of a mass in a mass–spring system maximum: (1) x = 0, (2) x = – A, or (3) x = + A? Why? (b) If m = 0.250 kg, k = 1000 N/m, and A = 0.10m for such a system, what is the mass’s maximum ...A 0.250-kg ball is dropped from a height of 10.0 cm onto a spring, as illustrated in Fig. 13.24. If the spring has a spring constant of 60.0 N/m, (a) What distance will the spring be compressed? (Neglect energy loss during ...If the displacement of an oscillator in SHM is described by the equation y = (0.25 m) cos [(314rad/s)t], where y is in meters and t is in seconds, what is the position of the oscillator at (a) t = 0, (b) t = 5.0s, and (c) ...
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