HW2 Ch2, Q 10,14,15,17,18,19, 20,21,23 X 6,11,12,25,29,30,42

Homework assignments from Hewitt, 9th ed.
The Questions (listed after a Q) are the same in the ninth edition.
The list after X consists of exercises; these are different in the ninth edition and I have
photocopies of the exercise set available.
Q is for question, X is for exercise
HW2 Chapter2, Q 10,14,15,17,18,19, 20,21,23
X 6,11,12,21,25,31,Exercise below
Consider a crate at rest on a factory floor. As a pair of workmen begin lifting it, does the
support force the floor applies to the crate increase, decrease or remain unchanged? What
happens to the support force on the workmen’s feet?
HW3 Due 19 October
Chapter4 Q 3,4,19,20,22,23,24,26,29 X 2,5,9,19,25,36 and following:
Five: Since an object has less weight on the surface of the Moon than on the surface of the
Earth, does it have less inertia on the Moon as well?
Nine: In an orbiting space shuttle, you are handed two identical boxes, one filled with sand
and the other with feathers. As you take the boxes, you let go of your pen and it remains in
place, floating in air. How can you determine which box is which without opening them?
Nineteen: Consider a heavy crate resting on the bed of a flatbed truck. When the truck
accelerates, the crate also accelerates and remains in place. Identify the force responsible for
accelerating the crate.
Fifty: When a car is moving in reverse, backing out of a driveway, the driver applies the
brakes. In what direction is the car’s acceleration?
Ch5 X4,7,13,19,21,30,37
One: Reconcile the fact that friction acts in a direction to oppose motion even though you rely
on friction to propel you forward when you walk.
Thirtyseven: A heavy bird sits on a clothesline. Will the tension in the clothesline be greater
if the line sags a lot or if it only sags a little?
HW 4 : Due 26 October
Chapter 6 X 2,11,10,20,21,39,43
Chapter 7 Q 2, 22 X 5,18,20,28 and two exercises below:
Seven: Two people who weigh the same climb a flight of stairs. Bill climbs the stairs
in 30 seconds while Dee Stract takes 40 seconds. Which person does more work? Which
uses more power?
Twentyfour: Why does the force of gravity do no work on (a) a bowling ball rolling
down a lane, and (b) a satellite in circular orbit about Earth?
HW5 : Due 2 November
Chapter 8: Q 11,25,26,29 and question below:
Twentyfive: If the string holding a whirling can in its circular orbit breaks, what kind of
force causes it to move in a straight-line path: centripetal, centrifugal, another or none?
Which law of physics supports your answer?
X 2,3,28,31,43,50 and two exercises below:
Eight: In this chapter we learn that an object may not be in mechanical equilibrium
even when the sum of the forces is zero. Explain.
Twentyone: When the line of action of a force passes through the center of mass of an
object, can the force produce a torque about the object’s center of mass?