Physics Homework Chapter 5

Physics Homework
Chapter 5
Name ____ANSWERS_________________
Date _________________________________
On Time
Follow instructions
Write the BEST, correct answer in the blank provided.
1. The product of the component of a force acting the direction of
displacement and the magnitude of the displacement is …..
2. The ….. of an object is due to the object’s motion.
3. The …… states that the net work done by all the forces acting on
an object is equal to the change in the object’s kinetic energy.
4. The ….. is associated with an object because of the position,
shape, or condition of the object.
5. The ….. is stored in the gravitational fields of interacting bodies.
6. The ….. is available for use when a deformed elastic object returns
to its original configuration.
7. A ….. is a parameter that is a measure of a spring’s resistance to
being compressed or stretched.
8. …... is defined as the sum of kinetic energy and all forms of
potential energy.
9. A quantity that measures the rate at which work is done or energy
is transformed is called …..
10. The unit of work in the international system is the .....
11. The unit of power in the international system equal to one joule
per second is the …..
12. The direction of work is unimportant; thus work is a ….. quantity.
13. The sign of work is important: work done by an object is …..,
work done on an object is …..
14. For linear motion, kinetic energy is equal to half the product of the
..... and the square of the linear .....
15. The force required to stretch a spring is directly proportional to the
16. For a stretched spring, potential energy is equal to half the product
of the….. and the square of the ..... through which the spring was
17. In doing work to raise the hammer of a pile driver, ….. must be
exerted over a given distance.
18. As the hammer is raised, its potential energy ….. thus work is done
on the hammer.
19. In its raised position, the hammer has greater ….. energy than …..
20. As the hammer is dropped, its potential energy is converted to
21. The potential energy of the raised hammer allows it to do ….. to
drive a pile into the ground.
22. Forces that conserve mechanical energy are called….. forces.
23. The force of friction is an example of a ..... force.
24. Measurements of potential energy depend on the definition of an
arbitrary ….. level.
1. ___work___________
2. ___kinetic energy____
3. _work-kinetic energy theroem_
4. _potential energy_____
5. _gravitational potential energy_
6. _elastic potential energy_
7. _spring constant______
8. _mechanical energy___
9. ___power__________
10. ___Joule___________
11. ____Watt__________
12. ____scalar__________
13. ___negative_________
14. ____mass__________
15. __spring constant____
16. __spring constant____
17. ___force___________
18. ___increases________
19. ___potential________
20. ___kinetic__________
21. ____work__________
22. __conservative______
23. __dissipative_______
24. ____zero__________
Place the letter(s) in the blank for all answers that make the statement correct.
25. Energy is (a) the capacity to do work. (b) acquired by an object
raised to an elevated position. ( c) acquired by an object that is set
in motion. (d) measured in work units.
26. In physics, work is done (a) in lifting an object from the floor to
the table top. (b) in supporting an object on your shoulder. ( c) in
reading your textbook. (d) in pushing an object across the floor.
27. The two factors that determine the amount of work done are (a) the
magnitude of the force exerted and the weight of the object moved.
(b) the distance the object is moved and the time required. ( c) the
displacement of the object and the magnitude of the force in the
direction of the displacement. (d) the magnitude of the force in the
direction of the displacement and the time required.
28. The work done by a varying force (a) equals force times distance.
(b) equals the area under a curve on a graph of magnitude of force
acting in the direction of motion versus distance through which the
force acts. ( c) may be approximated by the use of suitable
rectangles. (d) may be determined by using calculus.
29. Kinetic energy is (a) due to the position of a mass. (b) due to the
motion of a mass. ( c) due to the orientation of particles in a mass.
(d) proportional to the mass of the object concerned.
30. Potential energy (a) is energy due to the position of a mass. (b) is
energy due to the orientation of particles in a mass. ( c) is energy
due to the motion of a mass. (d) of position is proportional to the
mass of the object concerned.
31. A standard calorie (cal) (a) is defined as the amount of energy
required to increase the temperature of 1 ml of water by 1C0. (b)
equals 4.186 J. ( c) equals one food Calorie. (d) is required to be
present in the diet of a healthy and active person.
32. The law of conservation of mechanical energy (a) is illustrated by
a swinging pendulum. (b) states that the sum of the potential and
kinetic energies of an energy system remains constant when no
dissipative forces act on the system. ( c) involves frictional forces.
( d) involves systems where the work done is dependent on the
path length.
33. In physics, power is (a) the capacity for doing work. (b) the time
rate of doing work. ( c) the product of a displacement and the force
in the direction of the displacement. (d) a unitless quantity.
25. ___a___b___c___d___
26. ___a___________d___
27. ____________c_____
28. ______b___c___d___
29. ______b_______d___
30. __a___b___________
31. __a___b_______d___
32. __a___b___________
33. _______b__________
34. Use complete sentences to explain the block drop experiment. Include how that experiment is
important to the study of Chapter 5.
PROBLEMS: Show your work in completing the following. Write the answers with the correct number
of significant digits.
35. A wagon weighing 225 N is pulled a distance of 25.0 m at constant
speed in a straight line across a level floor. The wagon handle makes
an angle of 30.00 with the floor. The force applied to the handle is
15.0 N. How much work is done?
36. A student weighing 750.0 N ran up the stairs from the first floor to
the third floor in the elementary building. If this vertical distance is
8.00 m, how much work did the student do against gravity?
37. The physics teacher timed the student with a stop watch. If the
student took 14.0 s to climb the two flights of stairs, how much
power did the student exert?
35. __325J___________
36. __6.00 x 103 J______
37. _____429 W_______
38. What power is required to raise 9500.0 N of coal from a mine 60.0 m
38. ___3170 W_______
below the ground in a time of 3.00 minutes?
39. What potential energy is acquired by a hammer, mass 750.0 g, when
raised 35.0 cm off the ground?
39. ___257 J_________
40. If the hammer in the previous problem is dropped, with what speed
does it strike the ground?
40. ___2.62 m/s ______
41. If a ball has a mass of 50.0 g and a velocity of 8.50 m/s east, what is
its kinetic energy?
41. ___1.81 J_________
42. If the ball from the previous problem hits a spring with an elastic
constant of 375 N/m, how much does the spring compress?
42. ___98.1mm_______