A spring gun is used to lire a 0.02-kg projectile straight up into the air. The force constant of the spring is 800 N/s. and the spring is compressed 0.05 m. If there is no air resistance, how high above its initial position does the projectile go? Now suppose air resistance is important and the project goes 3 m high. What is the average air resistance force acting on the projectile on its way up? If the projectile is fired horizontally, what is its maximum speed? (Neglect resistance.)
Explanation / Answer
a) conserving energy, .5*k*x^2 = mgh -------> spring potential energy stored = gravitational P.E .5*800*.05^2 = .02*9.8*h so, h = 5.1 m