课程名称︰普通物理学甲上
课程性质︰大一必修
课程教师︰李庆德
开课学院：电资学院
开课系所︰电机工程学系
考试日期（年月日）︰2014/11/20
考试时限（分钟）：110分钟
是否需发放奖励金：是
试题 :
1. Multiple-choice Problems:{ 5 points each }
1. A Ferris wheel with a radius of 8.0 m makes 1 revolution every 10 s. When
he is at the top, essentially a diameter above the ground, he releases a
ball. How far from the point on the ground directly under the release point
does the ball land?
(A) 0 (B) 1.0 m (C) 8.0 m (D) 9.1 m (E) 16 m
2. A bureau rests on a rough horizontal surface ( s = 0.50, k = 0.40 ). A
constant horizontal force, just sufficient to start the bureau in motion,
is then applied. The acceleration of the bureau is:
(A) 0 (B) 0.98 m/s^2 (C) 3.3 m/s^2 (D) 4.9 m/s^2 (E) 8.9 m/s^2
3. A man wishes to pull a crate 15 kg across a rough floor by exerting a
force of 100 N. The coefficient of kinetic friction is 0.25. For the man to
do the least work, the angle between the force and the horizontal should
be:
(A) 0 (B) 14°(C) 43°(D) 66°(E) 76°
4. Given a potential energy function U(x), the corresponding force is in the
positive x direction if:
(A) U is positive
(B) U is negative
(C) U is an increasing function of x
(D) U is a decreasing function of x
(E) it is impossible to obtain the direction of from U
5. A sphere and a cylinder of equal mass and radius are simultaneously
released from rest on the same inclined plane sliding down the incline.
Then:
(A) the sphere reaches the bottom first because it has the greater inertia
(B) the cylinder reaches the bottom first because it picks up more
rotational energy
(C) the sphere reaches the bottom first because it picks up more rotational
energy
(D) they reaches the bottom together
(E) none of the above is true
6. Object A strikes the stationary object B head-on in an elastic collision.
The mass of A is fixed, you may choose the mass of B appropriately. Then:
(A) for B to have the greatest recoil speed, choose M_B = M_A
(B) for B to have the greatest recoil momentum, choose M_A >> M_B
(C) for B to have the greatest recoil kinectic energy, choose M_B >> M_A
(D) for B to have the least recoil speed, choose M_B = M_A
(E) for B to have the greatest recoil kinetic energy, choose M_B = M_A
7. A 3-g bullet is fired horizontally into a 10-kg block of wood suspended
by a rope from the ceiling. The block swings in an arc, rising 3 mm above
its lowest position. The velocity of the bullet was:
(A) unknown since the heat generated in the collision was not given
(B) 8.0 * 10^2 m/s
(C) 24.0 m/s
(D) 8.0 m/s
(E) 2.4 * 10^4 m/s
8. A 5.0-kg crate is resting on a horizontal plank. The coefficient of static
friction is 0.50 and the coefficient of kinetic friction is 0.40. After one
end of the plank is raised so the plank makes an angle of 30°with the
horizontal, the force of friction is:
(A) 0 (B) 18 N (C) 21 N (D) 22 N (E) 44 N
9. A pulley with a radius of 3.0 cm and a rotational inertia of 4.5 * 10 ^ -3
kg m^2 is suspended from the ceiling. A rope passes over it with a 2.0-kg
block attached to one end and a 4.0-kg block attached to the other. The
rope does not slip on the pulley. When the velocity of the heavier block is
2.0 m/s the total kinetic energy of the pulley and blocks is:
(A) 2.0 J (B) 4.0 J (C) 14 J (D) 22 J (E) 28 J
10. A cylinder of radius R = 6.0 cm is on a rough horizontal surface. The
coefficient of kinetic friction between the cylinder and the surface is
0.30 and the rotational inertia for rotation about the axis is given by
MR^2/2, where M is its mass. Initially it is not rotating but its center
of mass has a speed of 7.0 m/s. After 2.0 s the speed of its center of
mass and its angular velocity about its center of mass, respectively, are:
(A) 1.1 m/s , 0 (B) 1.1 m/s , 19 rad/s
(C) 1.1 m/s , 98 rad/s (D) 1.1 m/s , 200 rad/s
(E) 5.9 m/s , 98 rad/s
2. Calculation Problems:
1. {18 points} A disk-shaped pulley has mass M = 5 kg and radius R = 0.5 m.
It rotates freely on a horizontal axis, as in the figure below. A block of
mass m = 4 kg hangs by a string that is tightly wrapped around the pulley.
Assume the system starts at rest.
(a) Find the angular velocity of the pulley 4s after the block is released.
(b) Find the speed of the block after it has fallen 2 m.
(c) Repeat part(b) by using the principle of conservation of energy.
2. {16 points} On fast highways the outside edge of curve is raised. Such
banking prevent vehicles from slipping sideways if there is not enought
friction to provide the centripetal force. A car of mass 1500 kg rounds a
circular curve of radius 20 m that is banked at 37°to the horizontal. The
road is slippery, so the coefficient of static friction is only 0.15.
(a) Find the maximum safe speed at which the car can travel without
skidding.
(b) Is it possible for a car to go around a banked curve even if there is
no friction?
3. {16 points} A vertical chain has a length L and a mass M, which is
supposed to be distributed uniformlt through the length. The chain is
released with the bottom just touching a table.
(a) Find the force on the table as a function of the distance fallen by the
top end of the chain.
(b) Find the maximum force on the table during the free-fall process of the
chain to the table.
试题完
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备注：
(1) 试题皆是英文，如有不懂可以一直问助教
(2) 试题分A0, A1两份，仅第一部分选择题顺序不同，本试题为A1卷