Good Conceptual Questions (Not problems!) in Giancoli

10.1, Since r will be smaller, the distance required to complete a revolution will be shorter and the 
odometer will count miles too fast. 

10.2, While moving at a constant angular velocity it has neither angular nor tangential acceleration.
While angular velovity increases a point on the rim has both tangential and radial (centripetal) acceleration.
The tangential acceleration only changes if the angular acceleration changes, while the radial acceleration
changes even if the angular acceleration is constant.

10.4, Yes, if it is sufficiently far from the pivot point.

10.5, With your hands behind your head your moment of inertia is larger.

10.7, In both cases no, the torque can be balanced, but not the force, and vice versa.

10.10, They reach the bottom at the same time and with the same final velocity, but the more massive one has 
more kinetic energy.

10.14,  Moving the axis away from the center of mass will increase the moment of inertia.

10.15, The velocity at the top of the wheel points north. An east-pointing angular acceleration will result
in a south-pointing linear acceleration at this top point, and the angular speed will decrease.

11.1, (a) it would get longer because of conservation of angular momentum.

11.2, No.

11.3, Angular velocity will stay the same.

11.4, The accelerating wheel serves to increase the angular momentun, so the bike must rotate to keep it constant.

11.7, Inverting all the components does not affect the cross product.

11.10, Its angular momentum, relative to any single axis, remains constant.

11.11, The torques (forces) can be balanced while the forces (torques) are not.

11.13, You must try to tilt it to the left to get it to lift.

11.15, Without a second rotator the acceleration in the main rotor would cause the helicopter itself to rotate.
Secondary rotors take the form of small vertically aligned rotors on the tail, which provides lateral torque to 
steer the helicopter. Chinook helicopters (which fly around Rochester a lot) have two counter-rotating main rotors
that balance each other, eliminating any unwanted lateral torque.

12.2, No. At the bottom of the jump there is a net force acting on the jumper.

12.4, The torque from these weights must equal the torque from your body weight to keep the scale from rotating.
The weights must therefore act further from the pivot point.

12.5, In (a) the only torque keeping the wall in plae comes from the ground to the right of the submerged section
of the wall. On in (b) there is a large torque on the wall coming fromt the wieght of the dirt on the horzontal section
of concrete. 

12.7, If the person is low then the torque around the center of mass of the ladder acts to prevent it from slipping
out away from the wall. If the person is high (above the CM) then the torque from the person will act to rotate bottom
of the ladder away from the wall. 

12.8, The mass of the meter stick is the same as the rock.

12.10, (a) lay it circle side down (point up); (b) point down (circle side up; (c) lay it on its curved edge (as shown 
in figure 12-42)

13.2, The pressure in the bottles is sea-level atmospheric. At altitude, the ambient pressure is less, so the contents 
of the bottle get forced out.

13.3, Pressure is a function of depth, not geometry. In each container, the forces on the fluid from the walls are 
perpendicular to the walls themselves. This means that in the center cone the walls help support the weight of the fluid.
In the cone on the right, the walls add to the fluid weight.

13.4, The pin has a much smaller surface area, so the pressure is much higher with the pin. Your ability to peirce the skin
depends on the pressure, not the force.

13.6, By putting the cuff at the same height as the heart, the measured pressure is that of the heart pumping blood.
If the cuff is placed below the heart, the measured pressure will be that of the heart pumping, and the weight of blood
between the heart and the cuff (pressure will be read too high). Similarly, if the cuff is above the heart, the pressure
will be artificially low.

13.7, The density of ice is less than that of water. Since the ice cube weight is exactly balanced by the bouyancy force,
the mass of the ice cube must be exactly that of the displaced water. This means that as the ice melts the level of the 
water will remain constant.

13.9, Diet Coke must be less dense than water. Full strength Coke must be more dense than water.

13.10, Ships are mostly hollow, so they displace a large amount of water, and actually contain a relatively small amount 
of water.

13.11, The liquid in the longer leg of the pipe will fall under the force of gravity, which will create a lower pressure in 
this side of the pipe. This low pressure will pull the water out of the upper beaker.

13.12, Not really enough info given here, as you'd need to know how adding or removing sand will change the geometry of 
the barge. But what they're goin for here is that you need to add sand to make the boat sink deeper into the water. If 
you take sand away, the bouyancy force of the water will push the boat up higher.

13.15, Again, sort of a trick question. When you fill a balloon the air in it is actually compressed relative to the 
air outside (because the elasticity of the balloon privides an inward pressure). This means that, while the larger volume 
of the filled balloon displaces more air, and therefore is subject to a larger bouyancy force, it also has a higher density 
than the surrounding air. So the filled balloon will have a  larger apparent weight.

13.19, Yup....The air near the train gets dragged along in te train's wake. Since the air is then moving faster near the 
train than away from the train, there is a pressure gradient that could push a curious child into the train.

14.1, A child's swing, stringed instruments, clock pendulum, car pistons

14.2, Yes, as the oscillator passes through the equilibrium position.

14.5, Since max speed is A*sqrt(k/m), you could double A or increase k (or decrease m) by a factor of 4.

14.7, The frequency of a pendulum will decrease with increased altitude, so the clock will to lose time.

14.9, The displacement and velocity have the same sign when the mass is moving away fromt he equilibrium position. The 
acceleration and displacement are in the same direction when the object is moving toward the equilibrium part.

14.11, The reach the equilirium point at the same time since frequency is independent of amplitude.

14.12, w = sqrt(k/m), so frequency increases as mass decreases. Then your car bounces faster when empty.

14.17, By swinging the pan at the right frequency the system will resonate, and large standing waves will be established. 
by swinging it faster or slower than this, small, "incoherent" waves will result, but not large scale "sloshing".

14.18, Pumping your legs (or pushing someone) on a swing; noise-induced wine glass breaking; violent shaking in your 
buddy's crappy car at just the right engine speed

15.2, The wave speed is the speed at which energy travels down the length of the cord. The speed of a tiny peice of the 
cord is how fast it moves while vibrating up and down (perpendicularly to the wave's direction of travel).

15.3, The largest difference in height (4.3 m) occurs whent he lower boat is in a trough and the higher boat is at a peak, 
and the  smallest difference in height (2.5 m) occurs when the lower boat is at a peak and the higher boat is in a trough.
Thus the wave amplitude mus be 1/4 of this total change in height (think about it...), so A = 0.45 m.

15.4, (a) When struck vertically, a transverse wave will travel down the rod. (b) when stuck horizontally, a longitudinal 
wave will travel down the rod.

15.7, Bulk modulus....huh? You don't need to know this for the test, but the speed of sound is related to the medium's 
bulk modulus, B [v = sqrt(B/rho)]. Going from air to most solids, the bulk modulus increases by a lot more than the density.

15.8, Firstly, the waves are damped as they travel (energy is lost through mysterious, real-life effects). Beyond this, 
the energy carried by the waves get spread out over larger and larger circles, so at any point the "energy density must 
be less. This means the amplitude must decrease.

15.14, Touch it at a node.

15.15, The energy carried is carried by the whole wave, not just in single points. The energy in a standing wave is 
distributed in around the antinodes, not the nodes. 

15.16, Yes. A standing wave is a manifestation of constructive interference between the incident and reflected waves.

16.5, Music. Music is generally comprised of a large number of unique frequencies. Since music sounds approximately the 
same no matter how far you are from its source (except for loudness), the frequencies must all travel at the same speed.

16.10, A tube will only support wavelengths that will constuctively interfere in it. The length of a "filtering tube" 
can be chosen to cancel out most of the wavelengths present for a particular system.

16.11, The frets at the bottom of the neck correspond to shorter wavelengths (higher frequencies). For notes on the musical 
scale, the difference in wavelength between two notes decreases as frequency increases. So the fret spacing decreases for 
higher notes to keep the player ont he musical scale.

16.14, Points D and C would move further apart.

16.16, The wave frequncies are further apart for (a) since the beat frequency (f1-f2) is higher.

16.17, No there is not a doppler shift is there is no relative motion between the observer and the source.