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Question

While skydiving you are trained to deploy your primary canopy at an altitude of 5,500 feet above the ground. At the time of the deployment your velocity is equal to terminal velocity, 134mph. Your mass, prior to jumping, was 178 pounds with all your gear. It takes you exactly 76 seconds to touch the ground, what was the force of wind resistance from the parachute?

Answer

We cannot determine the force of wind resistance without the reference area of the parachute.

  • Q: What is the formula to calculate force of wind resistance? A: The formula for force of wind resistance is F=0.5*p*v^2*Cd*A where F is force, p is the density of air (in kg/m^3), v is the velocity of the object relative to the air (in m/s), Cd is the drag coefficient (unitless), and A is the reference area (in m^2).
  • Q: What is the mass of the skydiver in kg? A: The mass of the skydiver in kg is 178 lbs / 2.205 lbs/kg = 80.71 kg.
  • Q: What is the density of air at 5,500 feet above the ground? A: According to the standard atmosphere model, the density of air at 5,500 feet above the ground is approximately 0.83 kg/m^3.
  • Q: What is the velocity of the skydiver in m/s? A: The velocity of the skydiver in m/s is 134 mph * 0.44704 m/s/mph = 59.87 m/s.
  • Q: What is the reference area of the parachute? A: The reference area of the parachute is not given in the problem, so we cannot determine the force of wind resistance.