2018 年度日本政府（文部科学省）奨学金留学生選考試験
QUALIFYING EXAMINATION FOR APPLICANTS FOR JAPANESEGOVERNMENT (MEXT) SCHOLARSHIP 2018

学科試験問題EXAMINATION QUESTIONS

高等専門学校留学生
COLLEGE OF TECHNOLOGY STUDENTS

物理PHYSICS

注意 ☆試験時間は 60 分
PLEASE NOTE: THE TEST PERIOD IS 60 MINUTES

(2018)NationalityNo.
(Please print full name, underlining

PHYSICS

family name.)MarksName1.

An object with a mass of 4.0 kg being suspended by a massless string is at rest on
a rough plane inclined at an angle of 30 , as shown in the figure below. The string iskept to be parallel to the inclined plane. Answer the following three questions, using
the coefficient of static friction 0.20, the gravitational acceleration 9.8 m/s2 andGive your answers under two significant figures, after calculating under
three significant figures.

4.0 kg30(1) Find the maximal friction force between the object and the inclined plane.

(1)N(2) Find the minimal force to pull up the object along the inclined plane.

(2)

(3)

N

Let the object be at rest again. Then, after cutting the string, the object starts toslide down the slope due to gravity. Find the acceleration of the object during its
subsequent motion. Use the coefficient of kinetic friction 0.050.

(3)

m/s2

2.

Object B is moving at a speed of 6.0 m/s on a smooth horizontal plane towards
object A at rest, as shown in the left figure below. After the collision, as shown in
the right figure, objects A and B are scattered in directions at an angle of 60 and30 , respectively. Find the speeds and of objects A and B, respectively, where. Give youreach object has an identical mass and never rotates. Useanswers under two significant figures, after calculating under three significantfigures.

B30
BA

6.0 m/s

60

A

Before the collision

After the collisionm/sm/s3.

Consider a system with two boxes A and B connected by a sufficiently small tube
with a stopcock. Initially the stopcock is closed. As shown in the figure below, in
the initial state, a volume, an absolute temperature, and a pressure of an ideal gas inbox A are 0.020 m3 285 K, and 1.2 105 Pa, and those of an ideal gas in box B are0.040 m3 385 K, and 1.6 105 Pa, respectively. Answer the following fourquestions, using the gas constant 8.31 J/(mol K). Give your answers under two
significant figures, after calculating under three significant figures.
BA
0.040 m3
0.020 m3
285 K
1.2385 K
1.6

stopcock

105 Pa105 Pa(1) Find the number of moles nA for the ideal gas in box A.

(1)

mol

(2) Find the number of moles nB for the ideal gas in box B.

(2)

mol

(3) Find the absolute temperature T of the ideal gas, after the stopcock is opened andthe system is in thermal equilibrium.

(3)K(4) Find the pressure P of the ideal gas, after the stopcock is opened and the system isin thermal equilibrium.

(4)

Pa

4.

Answer the following three questions on the Doppler effect for sound. The soundsource and the observer move in the same straight line. Assume that the speed ofsound is 340 m/s. Give your answers under two significant figures, after calculating
under three significant figures.

(1) The observer at a speed of 30 m/s is approaching the stationary sound source thathas a frequency of 100 Hz. Find the frequency heard by the observer.

(1)

Hz

(2) The sound source, at a speed of 30 m/s, that has a frequency of 100 Hz isapproaching the stationary observer. Find the wavelength observed by the observer.

(2)m(3) The sound source that has a frequency of 100 Hz is moving at a speed of 30 m/s,
and the observer is moving at a speed of 40 m/s in the same direction (i.e. thesource is chasing the observer from behind). Find the frequency heard by theobserver.

(3)

Hz5.

Answer the following three questions. Give your answers under two significant
figures, after calculating under three significant figures.

(1) Find the total resistance of four resistors connected as shown below.
4.0
1.0

5.0
6.0

(1)
(2) Find the total capacitance of four capacitors connected as shown below.
4.0 F
1.0 F

5.0 F
6.0 F

(2)

F

(3)

In the circuit with four resistors and a galvanometer G as shown below, R is an
unknown resistance. Find the resistance R to keep the galvanometer to be 0 A.

4.0

5.0G

6.0

R

(3)

6.

Answer the following two questions. Use 3.14 as the ratio of the circumference ofa circle to its diameter (), and. Give your answers under two
significant figures, after calculating under three significant figures.

(1) Two infinitely long straight wires are placed in parallel, 4.0 m apart from eachother as shown in the figure below. Each wire carries a current of 4.5 A in the same
direction. Find the magnitude of the magnetic field at point P, 4.0 m apart from eachwire.
P

4.0 m4.5 A

4.0 m

4.0 m

4.5 A

(1)

A/m

(2) An infinitely long straight wire and a circular loop of wire of a radius of 1.0 m
are placed on a plane as shown in the figure below. The center (point Q) of the circle
is 3.0 m apart from the straight wire. Find the magnitude of the magnetic field at
point Q when each wire carries a current of 5.0 A in the directions indicated by thearrows.

5.0 A
Q
3.0 m
5.0 A

1.0 m
circular loopof wirestraight wire
(2)

A/m

7.

Answer the following three questions. Use the gravitational acceleration thek, and the gas constant R. It is unnecessary
electrostatic
to calculate numerical values of fractions and square roots.

(1) An object with a mass of m is thrown downward with an initial speed 0 from thepoint of a height h at time
. It reaches the ground at time
. Derive the).
position (height) of the object measured from the ground at time t ((1)(2) Three point charges q are placed at the corners of a square with a length of aside of a as shown in the figure below. Derive the magnitude of the electric field atcorner A.

qA

aqqa(2)

(3) Consider a system of an ideal gas of 1.0 mole monoatomic molecules in apiston-cylinder arrangement. An external force F pushes the piston with a distance x,
with giving a heat Q (i.e. the ideal gas is compressed and heated). Derive thetemperature change (rise) of the ideal gas.

(3)