Explain the difference between the short and long run

GM cuts jobs at its Australian manufacturing unit GM will cut 500 jobs, or about 12% of its workforce, at its Australian plant because of a sharp fall in demand for its locally-made "Cruze" small car. Source: The Wall Street Journal, April 8, 2013 As GM cuts its workforce, how will the marginal product and average product of a worker change in the short run? Suppose that before the cuts the marginal product of GM workers is below their average product. As the number of workers decreases, the marginal product of a GM worker and the average product of a GM worker in the short run. increases; decreases does not change; does not change decreases; decreases increases; increases decreases; increases

What is the law of diminishing returns? Explain why it applies only in the short run.