1. If you perform 10 joules of work lifting a 10-N box from the floor to a shelf, how high is the shelf? (1 point)
1 m<-------This one
2. How can a machine make work easier for you?
by decreasing the amount of work you do
by changing the direction of your force <------
by increasing the work done by the machine
none of the above
3. How can you make the work output of a machine greater than the work input? (1 point)by decreasing friction
by increasing the input force
by increasing the output distance
none of the above <------- This one
4. Reducing friction in a machine
decreases its actual mechanical advantage.
decreases the work output.
increases its efficiency. <------This one
increases its ideal mechanical advantage.
5. The ideal mechanical advantage of a pulley system is equal to the
distance the load has to move.
length of the rope.
number of rope segments supporting the load.
weight of the object being lifted. <------This one
6. A machine is classified as a compound machine if it
has moving parts.
has an IMA greater than 1.
is made up of two or more simple machines that operate together. <------
is very efficient.
7. What is transferred by a force moving an object through a distance?
8. A 10-kilogram bicycle is traveling at a speed of 2 m/s. What is the bike’s kinetic energy? (1 point)10 J
20 J <-------
9. A 4-kilogram cat is resting on top of a bookshelf that is 3 meters high. What is the cat’s gravitational potential energy relative to the floor if the acceleration due to gravity is 9.8 m/s2?
118 J <------This one
10. Nuclear power plants are designed to convert nuclear energy into what type of energy? (1 point)chemical
electrical <------This one
11. Which of the following statements is a consequence of the equation E = mc2?
Energy is released when matter is destroyed.
Mass and energy are equivalent.
The law of conservation of energy must be modified to state that mass and energy are conserved in any process.
all of the above <------This one
12. The kinetic energy of the pendulum bob in Figure 15-1 increases the most between locations (1 point)
A and B.
A and C. <--------
B and D.
C and D.
13. What property of an object is related to the average kinetic energy of the particles in that object?
temperature <------This one
14. Thermal energy depends on an object’s
phase (sold, liquid, or gas). <---This one
all of the above
15. How do you know that a sealed calorimeter is a closed system?
because temperature is conserved
because the masses of the sample and water are equal
because thermal energy is not transferred to the environment <----This one
because work is done on the test sample
16. The vacuum inside the thermos bottle shown in Figure 16-1 stops which type of thermal energy transfer to keep the liquid hot?
both a and b <---- This one
17. To which of the following does the first law of thermodynamics apply?
transferring thermal energy
doing work on a system
all of the above <----This one
18. The second law of thermodynamics states that thermal energy can flow from colder objects to hotter objects
only if work is done on the system. <----this one
when thermal expansion takes place.
19. One consequence of the third law of thermodynamics is that
heat engines have efficiencies less than 100 percent
in some energy conversions, energy is not conserved
engines cannot discharge waste heat
the work a heat engine produces is less than the waste heat it produces <----This one
Fill in the Blank
20. A machine is a device that changes a(an) ____________________.
21. Besides a reduction in friction, the only way to increase the amount of work output of a machine is to ____________________ the work input.
22. The mechanical efficiency of any machine is always ____________________ than 100 percent.
23. When a pole vaulter flexes the pole, the pole vaulter increases the pole’s ____________________ potential energy.
24. Wind turbines convert ____________________ energy into electrical energy.
25. Energy resources that exist in limited amounts and, once used, cannot be replaced except over the course of millions of years are called ____________________ energy resources.
26. The increase in volume of a material due to a temperature increase is called _________________________.