What is the potential problem with solar energy?

Rocket Physics Problem about Gravitational Potential Energy?

• A rocket of mass 6.0 kg takes off from the ground and goes straight up. During the first 100 meters of its ascent, the engine exerts a 80 newton upward force on the rocket. A. How much work does the engine do on the rocket during those first 100 meters? B. Assuming kinetic and potential are the only kinds of energy the rocket gains, how much kinetic energy does the rocket have at the moment it’s 100 meters above the ground? (Hint: You’ll need to use a formula for gravitational potential energy but not a formula for kinetic energy. Think about the relationship between work and energy. To keep the math less messy, approximate g as 10 m/s2.) C. At height 100 meters, the rocket has 1850 joules of kinetic energy, which is less than your part B answer. Is energy not conserved, or is something else going on? Where are the “missing” joules? I really need help with parts B and C especially. If someone could please help me out?

• Answer:

  A) W=F*d = 80*100 =8000 J BGravitational Potential Energy = mgh=6*10*100=6000 J G.P.E + Kinetic Energy = Work done 6000 +K.E = 8000 K.E = 2000 J C) The missing joules were used up to do work against air resistance and converted into other forms of energy like Heat energy.