课程名称︰普通物理学甲上
课程性质︰必修
课程教师︰赵治宇
开课学院:工学院
开课系所︰机械系
考试日期(年月日)︰2015/01/16
考试时限(分钟):170
是否发放奖励金:Yes
试题 : http://imgur.com/If8hhUn
1. Prove that the speed v of a string wave with string tension τ and string
density μ is given by τ ^(1/2) (10%)
v = ( —─)
μ
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2. Show that the intensity of sound wave is given by I = (1/2)ρvω^2(Sm)^2
(Sm is the displacement amplitude) (10%)
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3. (a) What's the principle and the application of a strain gauge;
(b) Describe the principle of equivalence for general theory of relativity)
(4%,4%)
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4. Derive the change in entropy delta S between the initial state(Vi,Ti) and
final state (Vf,Tf) of an ideal gas in a reversible process (Fig.1).
(Express your answer with Vi,Ti,Vf,Tf,n.) (10%)
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5. Derive the change in entropy delta S when n mole of an ideal gas doubles its
volume in a free expansion.
(You must derive the result by using statistical mechanisms.) (10%)
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6. In Fig.2, water stands at depth D = 30.0 m behind the vertical upstream face
of a dam of width W = 250 m. Find (a) the net horizontal force on the dam
from the gauge pressure of the water and (b) the net torque due to that
force about a horizontal line through O parallel to the (long) width of the
dam . (c) Find the moment arm of the torque. (12%)
习题
7. In Fig.3, a solid brass ball of mass 0.320 g will roll smoothly along a
loop-the-loop track when released from rest along the straight section.
The circular loop has radius R = 12.0 cm, and the ball has radius r << R.
(a)What is h if the ball is on the verge of leaving the track when it
reaches the top of the loop? If the ball is released at height h = 6.00R,
what are the (b) magnitude and direction of the horizontal force component
acting on the ball at point Q? (10%)
习题
8. The 0.800 kg cube in Fig.4 has edge lengths d = 6.00 cm and is mounted on an
axle through its center.A spring (k = 3600 N/m) connects the cube's upper
corner to a rigid wall.Initially the spring is at its rest length. If the
cube is rotated 3° and released, what is the period of the resulting SHM?
(10%)
习题
9. For an ideal gas. show that the relation between the gas temperature T and
rms speed and molar mass M is given by 3RT ^(1/2)
Vrms =( —─)
M
(10%)
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10. In Fig. 5, two blocks (m = 1.8 kg and M = 10 kg) and a spring (k = 200 N/m)
are arranged on a horizontal,frictionless surface. The coefficient of static
friction between the two blocks is 0.40. What amplitude of simple harmonic
motion of the spring–blocks system puts the smaller block on the verge of
slipping over the larger block? (10%)
习题