Problem Set U3P2&3: Energy and Momentum Conservation Types of Energy 1. If the kinetic energy of a 0.567kg mass is 1230J, what is its speed? 2. A weight lifter lifts a 150kg barbell to his chest, then over his head, and then drops the barbell to the floor. His chest is 1.7m above the ground and the maximum height is with arms stretched up is 2.1m. Calculate the change in gravitational potential energy from: floor to chest, chest to max, and max to floor. 3. Make a graph of gravitational potential energy vs. the position of the barbell labeling the intervals from the previous problem. What is the significance of the slope of this graph? 4. A 10,000kg spaceship orbits a 1x1024 kg planet. It moves from an orbit of 10,000,000m to 20,000,000m to 30,000,000m. Calculate the change in gravitational potential energy between these orbits. 5. Make a graph of gravitational potential energy vs. the position of the spaceship labeling the intervals from the previous problem. 6. A 0.3kg mass connected to a spring with a spring constant of 430 N/m starts at equilibrium. It oscillates horizontally compressing the spring by .1m, turns around at .2m, passes through equilibrium, and stretches the spring by .2m. Calculate the change in elastic potential energy from: equilibrium to -.1, -.1 to -.2, -.2 to 0, and 0 to +.2. 7. Make a graph of elastic potential energy vs stretch for the mentioned locations. Energy Conservation 1. For the spring described in the previous problems. What is the mass's speed at the four mentioned locations? 2. Use five bar graphs, to visually show that mechanical energy is conserved. 3. A sled slides down a gently curving hill and up over the top of a smaller hill. If the small hill has a height of 2m and the sled is traveling 1.4m/s, what height is the sled start at? (Ignore friction.) 4. A 2kg block slides down 14m ramp that makes a 30 angle with horizontal. What speed will the block have at the bottom of the ramp if it starts at the top and friction is ignored? 5. What speed will the block have if the coefficient of friction is 0.1? (Hint: don't forget to break F into components to find FN.) 6. In outer space, a 5.4kg block flies towards a spring at 2.7m/s. If the spring is compressed 0.12m before bring the block to rest, what is the springs spring constant? 7. A 750 N/m spring is compressed 4.5cm and a 0.33kg ball is placed on top of it. When the spring is released, to what height will the ball rise above its starting position