→ ian800726 :你真閒...＝ ＝...第五題的hint那裏是ln不是In 01/28 08:55
課程名稱︰普通物理學甲上
課程性質︰系內必帶
課程教師︰王立民
開課學院：工學院
開課系所︰土木工程學系
考試日期（年月日）︰98/10/15
考試時限（分鐘）：110min
是否需發放獎勵金：是，謝謝
（如未明確表示，則不予發放）
試題 :
普通物理平時考(CH4,5,6,7)
各題附圖：http://gs179.photobucket.com/groups/w300/MX8IHKBQY1/Untitled-1.jpg
1.In Fig. 1, a ball is launched with a velocity of magnitude 20.0m/s, at an
angle of 50.0° to the horizontal. The launch point is at the base of a ramp
of horizontal length d1 = 6.00 m and height d2 = 3.60 m. A plateau is located
at the top of the ramp. (a) Does the ball land on the ramp or the plateau?
When it lands, what are the (b) magnitude and (c) angle of its displacement
from the launch point?(15%)
2.In fig. 2, a tin of anti-oxidants (m1 = 1.0 kg) on a frictionless inclined
surface is connected to a tin of corned beef (m2 = 2.0 kg). The pully is
massless and frictionless. An upward force of magnitude F = 4.0 N acts on the
corned beef tin, which has a download accerlation of 5.5 m/s^2. What are (a)
the tension in the connectiong cord and (b) angle β? (c) What is the largest
value the magnitude of F may have without the cord becoming slack?(15%)
3.A book of mass mt = 4.0 kg is put on top of a block of mass mb = 5.0 kg.
Between the two blocks, the coefficient of static friction is 0.25, and the
coefficient of kinetic friction is 0.15. The assembly of blocks is now placed
on a horizontal, frictionless table (Fig. 3). Find the magnitudes of (a) the
maximum horizontal force that can be applied to the lower block so that the
blocks will move together and (b) the resulting accerlation of the blocks.
(20%)
4.In Fig. 4, a 1.34 kg ball is connected by means of two massless strings, each
of length L = 0.50 m, to a vertical, rotating rod. The strings are tied to
the rod with separation d = 0.60 m and are taut. The tension in the upper
string is 35 N. What are (a) the tension in the lower string, (b) the
magnitude of the net string force : Fnet on the ball, and (c) speed of the
ball?(15%)
5.Fig. 5 shows a 10.0 kg cord attached to a cart that can slide along a
frictional horizontal rail aligned along an x axis. The coefficient of
kinetic friction is 0.10. The left end of the cord is pulled over a pully,
of negligible mass and friction and at cord height h = 1.20 m, so the cart
slides from x1 = 3.00m to x2 = 1.00 m. During the move, the tension in the
cord is a constant 25.0 N. What work is done by (a) the tension force and (b)
the friction force? (c) What is the change in the kinetic energy of the cart
during the move?(15%)
x dx dx
[Hint:∫------------- = √(x^2+h^2) , ∫------------- = In(x+√(x^2+h^2)) ]
√(x^2+h^2) √(x^2+h^2)
6.A 230 kg crate hangs from the end of a rope of length L = 12.0 m. You push
horizontally on the crate with a varying force F to move it distance d= 4.00m
to the side (Fig. 6). (a) What is the magnitude of when the crate is in this
fianl position? During the crate's displacement, what are (b) the total work
done on it, (c) the work done by the gravitational force on the crate, and
(d) the work done by pull on the crate from the rope? Knowing that the crate
is motionless before and after its displacement.(20%)
x dx
[Hint:∫------------ = -√(a^2-x^2)]
√(a^2-x^2)
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