Conservation of Energy – Falling Objects (p12 13) – Kinetic Energy (p10 11) – (a) 0.513 J Gravitational Potential Energy 0.513 J (p8 9) Mass, Speed – 4.24 m/s Gravitational (a) 27 J 14.1 m/s potential energy is the 729 J work done in moving an 900 kg (a) 0.69 J object from the ground to 6 kg 5.48 m/s a certain height. 8 m/s 5.48 m/s 0.8 m/s (a) 60 J (a) 224 m/s 3750 J 3384 J Air resistance is 5 kg slowing the skydiver 8.5 kg 0.1 kg down. 7 N/kg 26 N/kg 150 m/s (a) 1.6 J 45 m 3.2 m 1500 m (a) 31.3 m/s 587 000 J (to 3 s.f.) (a) 810 000 J (a) 520 N 600 000 J 4680 J (a) to reduce 210 000 J 4680 J frictional forces so that the 9.2 m/s speed of the trolley won’t 6.75 J drop as much as it moves 1.96 m/s along the air track. 6.75 J (b) 0.008 J (approximately) 21.4 m/s 54 kg 150 m (a) 4 N/kg Mercury or Mars
Gravitational Potential Energy (p8 – 9) Gravitational potential energy is the work done in moving an object from the ground to a certain height. (a) 60 J 3750 J 5 kg 8.5 kg 7 N/kg 26 N/kg 45 m 1500 m (a) 520 N 4680 J 4680 J 6.75 J 6.75 J 54 kg 150 m (a) 4 N/kg Mercury or Mars Kinetic Energy (p10 – 11) Mass, Speed (a) 27 J 729 J 900 kg 6 kg 8 m/s 0.8 m/s 3384 J 0.1 kg 150 m/s (a) 31.3 m/s 587 000 J (to 3 s.f.) (a) to reduce frictional forces so that the speed of the trolley won’t drop as much as it moves along the air track. (b) 0.008 J (approximately) Conservation of Energy – Falling Objects (p12 – 13) (a) 0.513 J 0.513 J 4.24 m/s 14.1 m/s (a) 0.69 J 5.48 m/s 5.48 m/s (a) 224 m/s Air resistance is slowing the skydiver down. (a) 1.6 J 3.2 m (a) 810 000 J 600 000 J 210 000 J 9.2 m/s 1.96 m/s 21.4 m/s