The concept of conservation of energy states that the total mechanical energy of a closed system remains constant. If the only energy changes are in kinetic energy (mv²) and gravitational potential energy (mgh). What is the total mechanical energy of the system? OTotal Mechanical Energy mu? + mgh OTotal Mechanical Enerau 1mu?

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An object with mass m dropped from rest from height H, after travelling a distance and emerged horizontally from the bottom of the track with a velocity v and height of h. H The mechanical energy of the mass as it emerges from the bottom of the track. O mgH O mgh mgH + mv² Omgh + mv²

1. A roller-coaster car with a mass of 1200 kg starts at rest from a point 20 m above the ground. At point B, it is 9 m above the ground. [Express your answers in kilojoules (kJ).] a. What is the initial potential energy of the car? b. What is the potential energy at point B? c. If the initial kinetic energy was zero and the work done against friction between the starting point and point B is 40 000 J (40 kJ), what is the kinetic energy of the car at point B 2. The time required for one complete cycle of a mass oscillating at the end of a spring is 0.80 s. What is the frequency of oscillation?