307 Energy Problems

EVEN PROBLEMS = 32pts

ODD PROBLEMS = 32pts

MATH PROBLEMS need all 4 parts (1pt each)

  1. Free Body Diagram
  2. Equations written out
  3. Numbers
  4. Solve and Box your answer
Important conversion:
km x 1 hr x 1000m  = m
hr   3600s   km      s
  1. In 1994, Leroy Burrell of the United States set what was then a new world record for the men’s 100 m run. He ran the 1.00 × 102 m distance in 9.85 s. Assuming that he ran with a constant speed equal to his average speed, and his kinetic energy was 3.40 × 103J, what was Burrell’s mass?
  2. The fastest helicopter, the Westland Lynx, has a top speed of 4.00 × 102 km/h. If its kinetic energy at this speed is 2.10 × 107 J, what is the helicopter’s mass?
  3. Dan Jansen of the United States won a speed-skating competition at the 1994 Winter Olympics in Lillehammer, Norway. He did this by skating 500 m with an average speed of 50.3 km/h. If his kinetic energy was 6.54 × 103 J, what was his mass?
  4. In 1987, the fastest auto race in the United States was the Busch Clash in Daytona, Florida. That year, the winner’s average speed was about 318 km/h. Suppose the kinetic energy of the winning car was 3.80 MJ. What was the mass of the car and its driver?
  5. In 1995, Karine Dubouchet of France reached a record speed in downhill skiing. If Dubouchet’s mass was 51.0 kg, her kinetic energy would have been 9.96 × 104J. What was her speed?
  6. Susie Maroney from Australia set a women’s record in long-distance swimming by swimming 93.625 km in 24.00 h.
    a. What was Maroney’s average speed?
    b. If Maroney’s mass was 55 kg, what was her kinetic energy?
  7. The brightest, hottest, and most massive stars are the brilliant blue stars designated as spectral class O. If a class O star with a mass of 3.38 × 1031kg has a kinetic energy of 1.10 × 1042 J, what is its speed? Express your answer in km/s (a typical unit for describing the speed of stars).
  8. The male polar bear is the largest land-going predator. Its height when standing on its hind legs is over 3 m and its mass, which is usually around 500 kg, can be as large as 680 kg. In spite of this bulk, a running polar bear can reach speeds of 56.0 km/h.
    a. Determine the kinetic energy of a running polar bear, using the maximum values for its mass and speed.
    b. What is the ratio of the polar bear’s kinetic energy to the kinetic energy of Leroy Burrell, as given in item 1?
  9. Escape speed is the speed required for an object to leave Earth’s orbit. It is also the minimum speed an incoming object must have to avoid being captured and pulled into an orbit around Earth. The escape speed for a projectile launched from Earth’s surface is 11.2 km/s. Suppose a meteor is pulled toward Earth’s surface and, as a meteorite, strikes the ground with a speed equal to this escape speed. If the meteorite has a diameter of about 3 m and a mass of 2.3 × 105 kg,
    a)What is its kinetic energy at the instant it collides with Earth’s surface?
    b)what would the equivalent energy be in sticks of dynamite (1 stick = 1MJ)?
  10. In 1992, Ukrainian Sergei Bubka used a short pole to jump to a height of 6.13 m. If the maximum potential energy associated with Bubka was 4.80 kJ at the top of his jump, what was his mass?
  11. Naim Suleimanoglu of Turkey has a mass of about 62 kg, yet he can lift nearly 3 times this mass. (This feat has earned Suleimanoglu the nickname of “Pocket Hercules.”) If the potential energy associated with a barbell lifted 1.70 m above the floor by Suleimanoglu is 3.04 × 103 J, what is the barbell’s mass?
  12. In 1966, a special research cannon built in Arizona shot a projectile to a height of 180 km above Earth’s surface. The potential energy associated with the projectile when its altitude was 10.0 percent of the maximum height was 1.48 × 107J.What was the projectile’s mass? Assume that constant free-fall acceleration at this altitude is the same as at sea level.
  13. The highest-caliber cannon ever built (though never used) is located in Moscow, Russia. The diameter of the cannon’s barrel is about 89 cm, and the cannon’s mass is 3.6 × 104 kg. Suppose this cannon were lifted by airplane. If the potential energy associated with this cannon were 8.88 × 108 J, what would be its height above sea level?
  14. Situated 4080 m above sea level, La Paz, Bolivia, is the highest capital in the world. If a car with a mass of 905 kg is driven to La Paz from a location that is 1860 m above sea level, what is the increase in potential energy?
  15. The deepest mine ever drilled has a depth of 12.3 km (by contrast, Mount Everest has height of 8.8 km). Suppose you drop a rock with a mass of 2.00kg down the shaft of this mine.
    a) What would the rock’s kinetic energy be after falling 3.2 km?
    b) Neglecting air resistance and using the rock's kinetic energy, what would be the downward velocity of the rock at 3.2km?
    c) What would the potential energy, associated with the rock, be at that same distance?
    d) How long would the rock have been falling at 3.2km?
    e) Using time, determine the downward velocity of the rock at 3.2km
    f) Is b and e equivalent (+/- 5m/s)?
  16. Suppose a motorcyclist rides a certain high-speed motorcycle. He reaches top speed and then coasts up a hill. The maximum height reached by the motorcyclist is 250.0 m. If 2.55 × 105 J of kinetic energy is dissipated by friction, what was the initial speed of the motorcycle? The combined mass of the motorcycle and motorcyclist is 250.0 kg.