PHYS 101 Quiz 3

PHYS 101 Quiz 3 Liberty University

1. When we say work is done against a force, we mean the force does
2. Consider a situation where two moving objects collide, stick to each other, and move off together.
3. Consider a situation where a constant force of 25 N acts on an object having a mass of 2 kg for 3 seconds.
4. Consider a situation where two moving objects collide, stick to each other, and move off together.
5. The energy of a ball rolling up an inclined plane
6. You carry a 20-N box 5 m horizontally across a room. The work you do is
7. About how many 100-W light bulbs would you have to light up to use energy at the rate of one horsepower?
8. A kid slides down an icy (frictionless) hill starting from rest. At the top his gravitational potential energy is 500 J.
9. Which of the following quantities are conserved in an isolated system?
10. If a force on an object is aimed opposite the direction of the object’s velocity, the force does
11. Consider a situation where you exert a force F on a crate of mass m, moving it at a speed v a distance d across a floor in a time interval t.
12. What does it mean for a physical quantity in a system to be conserved?
13. Consider a situation where two moving objects collide, stick to each other, and move off together.
14. The mass of 1 m 3 of fresh water is 1,000 kg. At the top of a hydroelectric dam the potential energy of the water is
15. Consider a situation where two moving objects collide and rebound from each other.
16. Consider a situation where you carry a 20-N box up a flight of stairs, raising its elevation by 5 m.
17. Consider a situation where a skater pulls her arms inward, causing her rotation rate to speed up.
18. Consider a situation where two moving objects collide, stick to each other, and move off together.
19. The energy of a body moving across a horizontal surface is an example of kinetic energy.
20. Momentum is conserved only when there is no friction.
21. Consider a situation where you carry a 20-N box up a flight of stairs, raising its elevation by 5 m.
22. The momentum of an object never changes.
23. The energy stored in a pile driver is an example of gravitational potential
24. Consider a situation where you carry a 20-N box up a flight of stairs, raising its elevation by 5 m.
25. A person runs up a long flight of stairs in 10 seconds. If the person’s weight is 600 N and the vertical height of the stairs is 20 meters, the person’s power output is 1,200 W.
26. Select the closest matching pairs possible. 3 pts for each response.
27. Write your name and date. This problem should be solved using the principles of Energy Conservation found in Chapter 3.