SOME ENERGY/WORK QUESTIONS (Energy2Probs)

1)    What are some different units for energy?

2)    What are the types of energy and how are they measured?

3)    What are the types of mechanical energy?

4)    Describe the energy changes in a jack in a box ( a bobble head on a spring with friction). How would this look on a graph?

5)    Which type of mechanical energy does NOT depend on position?

6)    Give a typical amount of Calories of mechanical energy likely to be used by a typical teenager per week. How would this be calculated?

7)    What is the work done if I lift a 20 kg object 3 meters, then carry it at a constant speed horizontally for 5 meters?

8)    What is the purpose of a simple machine?

9)    Explain why all simple machines are really either levers or ramps:

10)  A parachutist with a mass of 40.0 kg jumps out of an airplane at an altitude of

5000 m. After the parachute deploys, the parachutist lands with a velocity of 6.00

m/s. Using the work–kinetic energy theorem, find the energy that was lost to air resistance

during this jump.

11)  A lever with an effort arm of 4 cm, and a resistance arm of 8 cm is attached to a 2 string pulley holding a 4 kg mass. If it takes 60 Newtons of force to push on the lever to lift the mass then find:

12)  A force of 1250 N is needed to move a crate weighing 3270 N up a ramp that is 4.55 m

long. If the elevated end of the ramp is 0.750 m high, what is the efficiency of the ramp?

13) A spring is pulled back from rest 20 cm with 40 N of force. If it hits a 3 kg mass, what is its starting eleastic energy? How fast is it going when it leaves the spring? (no friction). How high does it go?

14) ) A still person with a mass of 156 kilogram catches a 9 kilogram ball going 30 meters/second, which causes him to roll down a hill (starting at 1.636 m/s) .  What is the total energy after the collision?     If they are on the top of a 2 meter tall hill, what is the velocity at the bottom of the hill?