Transcript Physics MCAT Review

Passage IX Q 119-123 MCAT 3
Q 119
An artery is constricted at one location to 1/2
its normal cross-sectional area. How does
the speed of blood flow past the constriction
compare to the speed of blood flow in the
rest of the artery? (Assume ideal fluid flow)
A. It is 1/4 as fast
B. It is 1/2 as fast
C. It is 2 times as fast
D. It is 4 times as fast
Passage IX Q 119-123 MCAT 3
Q 120
Which of the following will occur when the
magnet used in the flowmeter discussed in
the passage is replaced with a stronger
magnet?
A. The electric field will reverse polarity.
B. The electric field will decrease.
C. The voltage will increase.
D. Blood will flow faster.
Passage IX Q 119-123 MCAT 3
Q 121
What is the volume flow rate of blood that
moves at 0.02m/s through an artery with a
diameter of 1.0 x 10-2 m?
A. 5.0 x 10-6 m3/s
B. 5 x 10-6 m3/s
C.  x 10-5 m3/s
D. 2 x 10-5 m3/s
Passage IX Q 119-123 MCAT 3
Q 122
If v increases by a factor of 2, by what factor
does the volume flow rate of blood through
the artery increase?
A. 20.5
B. 2
C. 4
D. 8
Passage IX Q 119-123 MCAT 3
Q 123
Which of the following describes the
direction if the magnetic force on an ion
moving in an artery past a flowmeter?
A. Parallel to both the direction of v and
the direction of B.
B. Parallel to the direction of v and
perpendicular to the direction of B.
C. Perpendicular to the direction of v and
parallel to the direction of B.
D. Perpendicular to both the direction of v
and the direction of B.
Passage XI Q 131-136 MCAT 3
Q 131
A radar signal is transmitted to Mercury
from Earth. The signal is reflected and
returns to Earth with a frequency that is 1.3
x 106 Hz. The frequency change is best
represented by which of the following.
A. Mercury was moving toward the Earth
at the time of the experiment.
B. Mercury was moving away from the
Earth at the time of the experiment.
C. Mercury was moving neither toward nor
away from the Earth at the time of the
experiment.
D. Mercury is not rotating.
Passage III Q 78-84 MCAT 4
Q 78
A stationary receiver detects a change in
frequency of the signal from a jet flying
directly away from it at 300 m/s. Which of
the following receivers will detect the same
change in frequency from a jet moving away
at 600 m/s?
A. A receiver moving at 900 m/s in the
opposite direction as the jet.
B. A receiver moving at 300 m/s in the
opposite direction as the jet.
C. A stationary receiver.
D. A receiver moving at 300 m/s in the same
direction as the jet.
Passage III Q 78-84 MCAT 4
Q 79
If the jet in Experiment 1 transmits a
2.5 x 106 Hz radio wave, what will be the
approximate change in frequency measured
at the receiver?
A. -1.2 Hz
B. -1.5 Hz
C. -2.2 Hz
D. -3.0 Hz
Passage III Q 78-84 MCAT 4
speed
speed
Q 80
Which of the following graphs best
illustrates the relationship between the speed
of the transmitter away from the receiver
and the increase in wavelength of the
received signal?
A.
B.
change in 
change in 
speed
D.
speed
C.
change in 
change in 
Passage III Q 78-84 MCAT 4
Q 81
As the speed of the jet flying away from the
jet increases, what happens to the distance
between adjacent peaks of the transmitted
wave, as measured at the receiver?
A. It decreases
B. It remains constant
C. It increases
D. It changes, but is not dependent on the
speed.
Passage III Q 78-84 MCAT 4
Q 82
Why are the percentages of the change in
frequency and wavelength much greater
when sound waves are used instead of radio
waves in these experiments?
A. Sound waves travel more slowly.
B. Sound waves have a much higher
frequency.
C. Sound waves have a much shorter
wavelength
D. Interference in the atmosphere affects
sound waves much more.
Passage III Q 78-84 MCAT 4
Q 83
A receiver is in a jet that is flying alongside
another jet that is emitting 2.0 X 106 Hz
radio waves. If the jets fly at 268 m/s, what
is the change in frequency detected at the
receiver?
A. 0 Hz
B. 0.09 Hz
C. 1.79 Hz
D. 3.58 Hz
Passage III Q 78-84 MCAT 4
Q 84
An astronomer observes a hydrogen line in
the spectrum of a star. The wavelength of
hydrogen in the lab is 6.563 x 10-7 m, but the
wavelength in the star’s light is measured at
6.56186 x 10-7. Which of the following
explains this discrepancy?
A. The star is moving away from Earth.
B. The wavelength of light that the star is
emitting changes constantly.
C. The frequency of light that the star is
emitting changes constantly.
D. The star is approaching Earth.
Magnetism
This field could be created by a magnet, or...
S
N
Magnetism
by a current loop.
What direction is the current in the loop?
Magnetic Forces RHR
A positive charge moves in a B-field that points to the
right. What direction is the force on the charge for
each case?
F = qvB sin 
Fingers with v, bend
v
F=0
F=0
fingers to B, thumb
points in the direction of
the force.
F big,
out
F smaller, in
B
F big, in
 is the angle between v and B.
F smallest,
in
Magnetic Forces, Wires
Find the direction of the force on the wire placed in a
B field.
F = qvB sin
F = IlB sin
F
I
B
qv becomes Il
B Fields caused by Currents
Compass needle and a wire
B Fields caused by Currents
Two currents
1
Due to wire 2
2
Due to wire 1
Forces equal and opposite, 3rd law
B Fields caused by Currents
Two currents
1
Due to wire 2
2
Due to wire 1
Forces equal and opposite, 3rd law
B Fields caused by Currents
1
1
Current loops
3
1
2
4
2
1
4
4
4
Net out
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3
3
3
1
4
2
2
3
Net into
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