-
8/4/2019 981 Physics
1/13
98-1 Med98
2pts/ (/)
1. Two balls of ideal motion, one is projectile and the other is
free fall, which both start to move at the same
time. Which statements are correct?(1)(2)(3)(4)
1) In the projectile motion, the object moves with constant
acceleration in the vertical direction.
2) The vertical positions of the two balls are identical at
identical times, while the horizontal position of
the projected ball increases linearly.
3) Kinematics can be applied to analyze both types of
motion.
4) Both types of motion do not provide any implication for the
dynamics, i.e, without any insights as to
mechanism caused the motion.
2. The figure () shows a boy swinging starting at a point higher
than P.
Consider the following distinct forces:
A. a downward force of gravity
B. a force exerted by the rope pointing from P to O
C. a force in the direction of the boy's motion.
D. a force pointing from O to P.
3.Which of the above forces is acting on the boy when he is at
position P?
1) A only
2) A and B
3) A and C4) A, B, and C
5) A, C, and D
4. A hunter raised a gun to shoot a monster. The monster was
scared, and immediately fell down vertically to
ground when shot. The hunter used two kinds of bullet: light and
heavy in weight, in the case of frictionless
air? (1)
1) The light bullet was able to shoot the monster.
2) The heavy bullet is not able to shoot the monster.3) Either
the light or the heavy bullet was able to shoot the monster.
4) Neither the light nor the heavy bullet was able to shoot the
monster.
5. A system of particles is known to have a total kinetic energy
of zero. Then, the momentum of the system
is zero. If a system of particles is known to have a total
momentum of zero, does it necessarily follow that
the total kinetic energy of the system is also zero? (2)
1) yes
2) no. why: ________________
-
8/4/2019 981 Physics
2/13
0 (0)00
6. Weighted hand in equilibrium condition depicted as the right
figure ().
(mg=50.0N, d=3.00cm, l=30.0cm) How much force does the Biceps
make? (3)
1) 30.0N
2) 50.0N
3) 500N
4) 300N
50 30 = F 3 F = 500(N)7. Two spheres have the same radius and
equal masses. One is made of solid aluminum, and the other is
made from a hollow shell of gold. Which one has the bigger
moment of inertia about an axis through its
center? (2)
1) solid aluminum
2) hollow gold
3) both is the same
I = r8. Which is the following statement true about the elastic
moduli of materials? (2)(5)
1) Bulk Modulus measures the resistance of a solid to a change
in its length.
2) Shear Modulus measures the resistance to motion of the planes
within a solid parallel to each other.
3) The tensile strain is the ratio of the external force to the
cross-sectional area.4) The tension stress is the ratio of the
change in length to the original length.
5) Young's modulus is the ratio of (tension stress)/(tensile
strain).
(1) Bulk Modulus measures the resistance of a solid to a change
in its volume.
(3) The tensile stress is the ratio of the external force to the
cross-sectional area.
(4) The tension strain is the ratio of the change in length to
the original length.
9. What does the following statements about the fluid is right?
(3)
1) the mass flow flux is defined as the velocity times its
cross-section.
2) the fluid is imcompressible because of its velocity kept
constant all the time.
3) the density of a fluid is defined as the ratio of its mass
per unit volume.
4) the specific gravity is defined as its weight per unit
volume.
(1) the volume flow flux is defined as the velocity times its
cross-section.
(2) the fluid is imcompressible because of its density kept
constant all the time.
(4) the specific weight is defined as its weight per unit
volume.
10. What does a Newtonian fluid mean? And what does a
non-Newtonian fluid mean? (3)
1) the air, water or small molecules are non-Newtonian
fluid.
-
8/4/2019 981 Physics
3/13
2) A Newtonian needs a start-up shearing stress.
3) A non-Newtonian means that the power law relation =(du/dy)^n
holds true, for the case of n>1 or
n
-
8/4/2019 981 Physics
4/13
2) period does not change.
3) period decreases.
( = )15. The moment of inertia of the ring is mr2(m:mass and
r:radius) in case of the ring hoop about central axis.
If the ring hoops on a hug(), what is the moment of inertia?
(4)
1) 0.5 mr2
2) 1 mr2
3) 1.5 mr2
4) 2 mr2
I = . + = + = 216. A gryoscope can be described by its
precessional motion. (2)(4)
1) The normal force produces a torque about the pivot, and this
torque is perpendicular to the axle.
2) Angular momentum of top's spin is changed by the torque,
results in top precesses about the z axis.
3) the precessional frequency increases as the frequency of
top's spin is increased.
4) precession is usually slow relative to the spinning motion of
the top.
(1) The gravity produces a torque about the pivot, and this
torque is perpendicular to the axle.
(3) the precessional frequency decreases as the frequency of
top's spin is increased. (
p = =
)
17. Which of the following statement is correct?
1) When the spins of the proton and neutrons comprising these
nuclei are paired, the overall spin of the
charged nucleus generates a magnetic dipole moment.
2) Larmor frequency is related to the nucleus-spin under
magnetic field.
3) the gyromagnetic ratio is a constant for a given nucleus.
4) The energy at the Larmor frequency is either absorbed or
emitted in a transition between the two
excitation states of the spin systems.
5) The detection and acquisition of RF signals at the
characteristic Larmor frequency constitutes the
basic information for NMR spectroscopy and imaging.
18. If the flow of a fluid , as shown in the figure, from
laminar to turbulent, when: (1)(2)(4)
1) Reynold number increases.
2) the fluid goes above some critical speed.
3) the viscosity of the fluid becomes much greater.
4) the viscosity of the fluid becomes much smaller.
(1) Reynold number
(3) the viscosity of the fluid becomes much smaller. ( = Re)
-
8/4/2019 981 Physics
5/13
19. Water flows through a 1-cm diameter pipe connected to a
1/2-cm diameter pipe. Compared to the speed
of the water in the 1-cm pipe, the speed in the 1/2-cm pipe is:
(5)
1) one quarter
2) one half
3) the same
4) double
5) four times.
= 1/2-cm pipe 1-cm pipe 1/44
20. A blood platelet drifts along with the flow of blood through
an artery that is partially blocked. As the
platelet moves from the wide region into the narrow region, the
blood pressure: (2)
1) increases
2) decreases
3) stays the same
4) drops to zero.
= BernoullisEquationP + g y + = v21. A layer of water is between
a stationary surface and a moving plate as shown in 2 figures
below.
The plate velocities in each figure are the same. The water in
the 2nd figure is twice as deep as the water
layer in the 1st figure. The water layer is laminar. Which is
correct? (5)1) F1 equals F2
2) F1 equals 4F3
3) F1 equals F2/2
4) F1 equals F2/4
5) F1 equals 2F2.
F = A Fl = = 222. The travelling wave represented by y(x,t) = A
sin(t+kx). (4)
1) t+kx must be a constant.
2) the wave travels in the +x direction
3) wave moves with a speed of +/k
4) y'(x,t) = A sin(t+kx+kx), the phase difference between
y(x,t)
and y'(x,t): is =2x
23. Interference of two waves happens to be:
1) constuctive interference when two waves are in phase,
2) beats as the waves added with their slightly different
frequencies,
3) standing wave when the amplitude of resultant wave at
antinodes varies with position.
-
8/4/2019 981 Physics
6/13
4) resonance when nodes occur at both ends, for a string clamped
at both ends.
24. (3)
1)
2)
3)
4) ()
(1)
(2) v = (3) v = 331 + 0.6t(4) ()
25. ?1)
2)
3)
4)
26. (1)(2)
1)
2) 3) (stress relaxation)
4) (creep)
(3)(creep)(4)(stress relaxation)
27. d 1 1 d
= + dt E dt
()=*()
1)
2)
3) = E
(1)
(3) = E;
-
8/4/2019 981 Physics
7/13
28. : (3)(4)
1)
2)
3)
4)
(1)(2)(3)Elaticityp.16
29. 10m/s
f=600Hz 50m/s
350m/s
1) f * (350-10)/(350-50) Hz
2) f * 350/(350+40) Hz
3) f * (350+10)/(350+50) Hz
4) f * (350+10)/(350-50) Hz
3pts/1. Each levers of human body are shown in the right
figures.
(a) indicate the class of lever for each status, by filling
class I or II or III in each blank.
(b) Filling in the mechanical advantage (M.A.) (>1,=1,1 n
-
8/4/2019 981 Physics
8/13
(3)Poiseuille's Equation 1/2 1/16
RFlow resistance = 163. A Newtonian fluid with a dynamics or
absolute viscosity of 0.98Ns/m2 and a specific gravity of 0.91
flows through a 25mm diameter pipe with a velocity of 2.6m/s,
please calculate Reynold Number, and what
kinds of flow type the fluid is?
= = (.9).().98 = 60.36 (d
5. 1) A venturi meter can be used to measure fluid
flowbymeasuring pressure differences. Using the Bernoulli Equation
to
derive the volume flow in terms of v, A, .
2) Write down and explain briefly, the 3 different cases
that
can be applied by the application of the Bernoulli equation.
(1) Q = = (1) Bernoullis Equation
+
+
=
+
+
y1=y2 = (2)(1) = = = (2) Q = ; ;
(2)
-
8/4/2019 981 Physics
9/13
6. 1) Which is the correct way to lift a weight? _____ (a or
b)
2) Explain __________
(1) b
(2)
7. Draw the force diagram for the spine of a man bending over to
lift a weight.
8. Try to estimate the force exerted on your eardrum if swimming
at the bottom of a pool with a 10m depth.
We approximate the area of a human eardrum with a reasonable
1cm2.
P = + = 1.0336 + 10 10
= 1.0336 + 104
10;4
= 2.0336
2.0336 1 = 2.0336 w9. What does the Fahraeus-Lindqvist effect,
which the blood viscosity drops significantly as the vessel
diameter is less than 1mm mean?
1mm 1mm
10. 1) What is the differences between the Newtonian and
non-Newtonian fluid?
2) And try toplot the characteristic curve in terms of (sharing
stress), d/dt(rate of shearing strain).
3) Why the blood flow is a non-Newtonian fluid at the low shear
rate? Explain it qualitatively.
4) What is the Fahraeus-Lindqvist effect?
(1)
-
8/4/2019 981 Physics
10/13
(2) Newtonian fluidShear thinning Shear thickening
(3)(shear rate)
(4) 1mm
11. Try to estimate the force exerted on your eardrum if
swimming at the bottom of a pool with a 10m depth.
We approximate the area of a human eardrum with a reasonable
1cm2.
P = + = 1.0336 + 10 10
= 1.0336 + 104
10;4
= 2.0336
2.0336 1 = 2.0336 w12. Write the expression for:
a) Moment of inertia (I) in terms of density: __________
b) Parallel-Axis Theorem: ____________
(a)
I = = =
(b) I = + 13. Find out the direction and the magnitude of the
precessional frequency p of the gyroscopy in terms of
the I (inertia moment), M(the mass of the gyro) , and (the
rotation frequency of the gyro).
dtd
Ld = dL
(
) = I
-
8/4/2019 981 Physics
11/13
Ld = dL L = = = L = p = = p L = h Mg = I p = = p( =p L)
14. Poiseuille's equation describes the rate of flow of fluid in
a round tube depends on: _________________
It depends on the viscosity of the fluid, the pressure
difference, and the dimension of the tube.
15. A student holds the axle of the spinning wheel, which is
spinning in a horizontal plane with an angular
momentum Li upward, while seated on a stool which is free to
rotate, and the student and the stool are all
initially at rest. What happens and what the direction and
magnitude of the net angular momentum L of the
stool and the student is, if the students invert the wheel
upside-down, in terms of Li.
L = L = = + = 2
16. A person with constricted arteries will find that they may
experience a temporary lack of blood to the
brain, called a Transient ischemic attack (TIA). Explain in
terms of dynamic fluid mechanics.
Q = ;8 QRL(P1-P2)RFlow resistance = = 8r
17. Describe the transmission and reflection of wave propagation
along rope linked with two different
densities, by drawing figures.
18. 1) What is the magnetic spin moment and the gyromagnetic
ratio for the proton, in terms of L(angular
momentum), e(electric current), and mp (mass of the proton)?
2) Write down the frequency of the nucleus magnetic resonance,
if the gyromagnetic ratio, the
external magnetic field is , B respectively.
3) Write down the population ratio, the so called Saha equation,
between the two states of a spin
one-half system.
4) Why do we choose the hydrogen atoms as the main MRI sources,
in a human body?
-
8/4/2019 981 Physics
12/13
19. 1) ()
2)
(1)
FT = mV
T
(2)
20. 1) MRIT1T2
2) T1(Malignant Tissues)(normal tissues): ()
21. A modeB mode M modeA mode _____
B mode _____M mode_________
22.
23. ________________
_________
10pts/
1. a) Using a mathematical approach to describe the Simple
Harmonic Motion of a spring-mass system.
b) Describe the physics behavior of Forced Oscillations.
(a) = kx = m
= 1 a = 2
=
xt = A cos + = ( = )
-
8/4/2019 981 Physics
13/13
(b) Forced Oscillation F(t)=F0cos(t)
Ft kx = ma = m x=Acos(t)Am + k cost = Ft = cos Am + k = A = ;: =
;: =
Forced Oscillation0 xA(resonance)
2. a) Define the viscosity of fluids.
b) Describe the relation between shearing stress and rate of
shearing strain for Newtonian and
Non-Newtonian properties of blood.
(a) (, viscosity)
= = 1 Poise = 1g ; ;
(b) low shear rate Non-Newtonian fluid high shear rate
Newtonian fluid
3. 1010
a)
b)
c)
d)
