1. Naim Suleimanoglu of Turkey has a mass of 62 kg (136 lbs), yet he can lift 3 times his mass. This feat has earned him the nickname "Pocket Hercules". How much potential energy would a barbell have if he lifted the barbell 1.7 m above the floor?
2. Susie Maroney from Australia set a women's record in long-distance swimming by swimming 93.625 km in 24 h.
(a) What her average speed in m/s?
(b) If she had a mass of 55 kg, how much kinetic energy did she have?
3. A 7.85×1011 kg comet strikes the Earth at a speed of 25 km/s. Which is greater, the amount of kinetic energy this comet had or the amount of energy released by the largest nuclear weapon ever built (4.2×1015 J = 100 million tons of TNT)? Such a comet collision has been suggested as having caused the extinction of the dinosaurs.