# Conservation of Energy Q

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1. On a force vs. position graph, the area under the curve is a representation
work
2. Consider a plot of displacement (x) vs. applied force (F) for an ideal elastic spring. The slope of the curve would be
the reciprocal of the spring constant
3. In the SI System of units, power has the same units as
W/s
4. As compared to Jack, Jill does twice the work in half the time. Jill's power output is
Four times Jack's power output
5. You throw a ball straight up. Compare the sign of the work done by gravity while the ball goes up with the sign of the work done by gravity while it goes down
Work - on the way up and + on the way down
6. You and your friend want to go to the top of the Eiggel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. Compare the gravitational potential energy (U) of you and your friend, after you both reach the top
Both of you have the same amount of potential energy
7. The total mechanical energy of a system
Is constant, only if conservative forces act
8. An acorn falls from a tree. Compare its kinetic energy K, to its potential energy U
K increases and U decreases
9. Describe the energy of a car driving up a hill
both kinetic and potential
10. Two identical balls are thrown from the top of building with the same speed. Ball 1 is thrown horizontally, while ball 2 is thrown at an angle of p above the horizontal. Neglecting air resistance, which ball will have the greatest speed when hitting the ground below
both balls reach the ground with the same speed
11. Swimmers at a water park have a choice of two frictionless water slides. ALthough both slides drop over the same height, h,  slide 1 is straight while slide 2 is curved, dropping quickly at first and then leveling out. How does the speed v1 of a swimmer reaching the end of slide 1 compares with v2, the speed of a swimmer reaching the end of slide 2
• v1=v2
• conservation energy, energy can not be created or destroyed
12. A lightweight object and a very heacy object are sliding with equal speeds along a level frictionless surface. They both slide up the same frictionless hill. Which rises to a greater height?
THey both slide to the same height
13. Two blocks of masses m1 and m2 are released from the top of two frictionless inclined planes of the same height making 30 and 60 degree angles with the horizontal direction, respectively. WHich of the blocks is going faster when it reaches the bottom of its respective incline?
both blocks have the same speed at the bottom
14. A ball drops some distance and gains 20 J of kinetic energy. Do not ignore air resistance. How much gracitational potential energy did the ball lose?
more than 30 3
15. If you push twice as hard against a stationary brick wall, the amount of work you do
remains constant at zero
16. A person applies a constant force of 20 N to a rock of mass 1000kg for a total of 2 sec. What is the work done by this person if the rock does not move at all by this applied force
0J
17. A person carries a mass of 10 kg and walks along the +x axis for a distance of 100m with a constant velocity of 2 m/s. What is the work done by this person?
0J
18. A person applies a constant force on an object of mass 20 kg that causes the object to move horizontally at a constant speed of 0.2 m/s through a distance of 0.8 m. What is the work done on the object
0J
19. Work done by STATIC FRICTION is always
zero
20. A simple pendulum, consisting of a mass m and a string of length l, swings upward, making an angle p with the vertical. The work done by the tension force is
zero
21. IF the net work done on an object is positive the objects kinetic energy
increases
22. If the net work done on an object is negative, then the object's kinetic energy
decreases
23. If the net work done on an object is zero, then the objects kinetic energy
remaints the same
 Author: Anonymous ID: 184567 Card Set: Conservation of Energy Q Updated: 2012-11-20 03:05:10 Tags: AP Physics Folders: Description: AP Physics Show Answers: