大学物理双语-练习题.doc

Chapter 1 Particle Kinematics I) Choose one correct answer among following choices1. An object is moving along the x-axis with position as a function of time given by x=x(t). Point O is at x=0. The object is definitely moving toward O when A. B. C. D. 2. An object starts from rest at x=0 when t=0. The object moves in the x direction with positive velocity after t=0. The instantaneous velocity and average velocity are related by A. B. C. D. can be larger than, smaller than, or equal to 3. An object is moving in the x direction with velocity , and is nonzero constant. With when t=0, then for t0 the quantity is A. Negative. B. Zero. C. Positive.D. Not determined from the information given.4. An object is moving on the xy-plane with position as a function of time given by r = a t2 i+ b t2 j (a and b are constant). Which is correct? A. The object is moving along a straight line with constant speed. B. The object is moving along a straight line with variable speed.C. The object is moving along a curved path with constant speed.D. The object is moving along a curved path with variable speed.5. An object is thrown into the air with an initial velocity m/s. Ignore the air resistance(空气阻力). At the highest point the magnitude of the velocity is ( )(A) 0 (B) 4.9m/s (C) 9.8m/s (D) m/s 6. Two bodies are falling with negligible air resistance, side by side, above a horizontal plane. If one of the bodies is given an additional horizontal acceleration during its descent, it A. strikes the plane at the same time as the other body.B. strikes the plane earlier than the other body. C. has the vertical component of its velocity altered.D. has the vertical component of its acceleration altered.7. A toy racing car moves with constant speed around the circle shown below. When it is at point A its coordinates are x=0, y=3m and its velocity is 6m/s . When it is at point B its velocity and acceleration are: A. -6m/sand 12m/s2, respectively. B. 6m/s and -12m/s2 , respectively. C. 6m/sand 12m/s2, respectively. D. 6m/s and 2m/s2 , respectively.8. A stone is tied to a 0.50-m string and whirled at a constant speed of 4.0m/s in a vertical circle. Its acceleration at the bottom of the circle is: A. 9.8m/s2, up B. 9.8m/s2, down C. 8.0m/s2, up D. 32m/s2, up9. A boat is able to move through still water at 20m/s. It makes a round trip to a town 3.0 km upstream. If the river flows at 5m/s, the time required for this round trip is: A. 120 s B. 150 s C. 200 s D. 320 s II) Fill in the empty space with correct answer1. A particle goes from x=-2m, y=3m, z=1m to x=3m, y=-1m, z=4m. Its displacement is : .2. The x-component of the position vector of a particle is shown in the graph in Figure as a function of time.(a) The velocity component vx at the instant 3.0 s is .(b) When is the velocity component zero ? The time is . (c) Is the particle always moving in the same direction along the x-axis? .3. The angle turned through by a wheel is given by at+bt2, where a and b are constants. Its angular velocity , and its angular acceleration .4. When a radio wave impinges on the antenna of your car, electrons in the antenna move back and forth along the antenna with a velocity component vx as shown schematically in Figure . Roughly sketch the same graph and indicate the time instants when(a) The velocity component vx is zero; (b) The acceleration component ax is zero; (c) The acceleration has its maximum magnitude. 5. A car is traveling around a banked, circular curve of radius 150 m on a test track. At the instant when t=0s, the car is moving north, and its speed is 30.0 m/s but decreasing uniformly, so that after 5.0 s its angular speed will be 3/4 that it was when t=0s. The angular speed of the car when t=0s is , the angular speed 5.0 s later is , the magnitude of the centripetal acceleration of the car when t=0s is , the magnitude of the centripetal acceleration of the car when t=5.00s is , the magnitude of the angular acceleration is , the magnitude of the tangential acceleration is .6. A projectile is launched at speed v0 at an angle (with the horizontal) from the bottom of a hill of constant slope as shown in Figure. The range of the projectile up the slope is .III) Calculate Following Problems:1. An object with mass m initially at rest is acted by a force, where k1 and k2 are constants. Calculate the velocity of the object as a function of time.2. You are operating a radio-controlled model car on a vacant tennis court. Your position is the origin of coordinates, and the surface of the court lies in the xy-plane. The car, which we represent as a point, has x- and y-cooridnates that vary with time according to x=2.0m-(0.25m/s2)t2 , y=(1.0m/s)t+(0.025m/s3)t3 . a. Find the cars instantaneous velocity at t=2.0s.b. Find the instantaneous acceleration at t=4.0s.3. An object moves in the xy-plane. Its acceleration has components ax=2.50t2 and ay=9.00-1.40t. At t=0 it is at the origin and has velocity .Calculate the velocity and position vectors as functions of time.4. An automobile whose speed is increasing at a rate of 0.600 m/s2 travels along a circular road of radius 20.0 m. When the instantaneous speed of the automobile is 4.00 m/s, find (a) the tangential acceleration component, (b) the radial acceleration component, and (c) the magnitude and direction of the total acceleration. 5. Heather in her Corvette accelerates at the rate of (3.00-2.00) m/s2, while Jill in her Jaguar accelerates at (1.00+3.00) m/s2. They both start from rest at the origin of an xy coordinate system. After 5.00 s, (a) what is Heathers speed with respect to Jill, (b) how far apart are they, and (c) what is Heathers acceleration relative to Jill?Chapter 2 Newtons laws of motionI) Choose one correct answer among following choices1. In the SI, the base units(基本单位) for length, mass, time are ( )(A) meters, grams, seconds. (B) kilometers, kilograms, seconds. (C) centimeters, kilograms, seconds. (D) meters, kilograms, seconds. 2. Which one of the following has the same dimension(量纲) as time ( )(A) (B) (C) (D) 3.Which of the following quantities are independent(无关) of the choice of inertial frame(惯性系)?(A) (B) (C) (D) W4. Suppose the net force F on an object is a nonzero constant. Which of the following could also be constant? A. Position. B. Speed. C. Velocity. D. Acceleration.5. An object moves with a constant acceleration . Which of the following expression is also constant? ( )(A) (B) (C) (D) 6. An object moving at constant velocity in an inertial frame must:A. have a net force on it. B. eventually stop due to gravity.C. not have any force of gravity on it. D. have zero net force on it.7. A heavy ball is suspended as shown. A quick jerk on the lower string will break that string but a slow pull on the lower string will break the upper string. The first result occurs because:A. the force is too small to move the ball B. action and reaction is operatingC. the ball has inertia D. air friction holds the ball back8. A constant force of 8.0 N is exerted for 4.0 s on a 16-kg object initially at rest. The change in speed of this object will be:A. 0.5m/s B. 2m/s C. 4m/s D. 8m/s9. A wedge rests on a frictionless horizontal table top. An object with mass m is tied to the frictionless incline of the wedge as shown in figure. The string is parallel to the incline. If the wedge accelerates to the left, when the object leaves the incline, the magnitude of its acceleration is A. gsin B. gcos C. gtan D. gcot 10. A crane operator lowers a 16,000-N steel ball with a downward acceleration of 3m/s2. The tension force of the cable is:A. 4900N B. 11, 000N C. 16, 000N D. 21, 000N11. A 1-N pendulum bob is held at an angle from the vertical by a 2-N horizontal force F as shown. The tension in the string supporting the pendulum bob (in newtons) is:A. cos B. 2/ cos C. D. 112. A car moves horizontally with a constant acceleration of 3m/s2. A ball is suspended by a string from the ceiling of the car. The ball does not swing, being at rest with respect to the car. What angle does the string make with the vertical?A. 17 B. 35 C. 52 D. 7313. A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30 above the horizontal. The mass of the crate is:A. 3.3kg B. 3.8kg C. 5.7kg D. 6.5kgII) Fill in the empty space with correct answer1. A 2.5 kg system has an acceleration . There are two forces acting on the system, and One of the forces is. The other force is .2. Two masses, m1 and m2, hang over an ideal pulley and the system is free to move. The magnitude of the acceleration of the system of two masses is . The magnitude of the tension in the cord is .3. You are swinging a mass m at speed v around on a string in circle of radius r whose plane is 1.00 m above the ground as shown in Figure. The string makes an angle with the vertical direction. (a) Apply Newtons second law to the horizontal and vertical direction to calculate the angle is .(b) If the angle = 47.4 and the radius of the circle is 1.50 m, the speed of the mass is .(c) If the mass is 1.50 kg, the magnitude of the tension in the string is .(d) The string breaks unexpectedly when the mass is moving exactly eastward. The location the mass will hit the ground is .III) Calculate Following Problems:1. A wedge with mass M rests on a frictionless horizontal table top. A block with mass m is placed on the wedge, and a horizontal force F is applied to the wedge. What must be the magnitude of F if the block is to remain at a constant height above the table top?2. The mass of blocks A and B in Figure are 20.0kg and 10.0kg, respectively. The blocks are initially at rest on the floor and are connected by a massless string passing over a massless and frictionless pulley. An upward force F is applied to the pulley. Find the accelerations a1 of block A and a2 of block B when F is (a) 124N ; (b) 294N ; (c) 424N.3. An object is drop from rest. Find the function of speed with respect to time and the terminal speed. Assuming that the drag force is given by D = bv2. 4. A small bead can slide without friction on a circular hoop that is in a vertical plane and has a radius of 0.100m. The hoop rotates at a constant rate of 4.00rev/s about a vertical diameter.(a) Find the angle at which the bead is in vertical equilibrium.(b) Is it possible for the bead to “ride” at the same elevation as the center of the hoop?(c) What will happen if the hoop rotates at 1.00rev/s.Chapter 3 Linear momentum, Conservation of momentumI) Choose one correct answer among following choices1. An object is moving in a circle at constant speed v. The magnitude of the rate of change of momentum of the object A. is zero. B. is proportional to v. C. is proportional to v2. D. is proportional to v3.2. If the net force acting on a body is constant, what can we conclude about its momentum?A. The magnitude and/or the direction of may change. B. The magnitude of r remains fixed, but its direction may change.C. The direction of remains fixed, but its magnitude may change.D. remains fixed in both magnitude and direction.3. If is the impulse of a particular force, what is ? A. The momentum B. The change in momentum C. The force D. The change in the force4. A variable force acts on an object from to . The impulse of the force is zero. One can conclude that A. and . B. but possibly .C. possibly but . D. possibly and possibly .5. A system of N particles is free from any external forces. Which of the following is true for the magnitude of the total momentum of the system? A. It must be zero. B. It could be non-zero, but it must be constant.C. It could be non-zero, and it might not be constant.D. The answer depends on the nature of the internal forces in the system.6. The x and y coordinates of the center of mass of the three-particle system shown below are:A. 0, 0 B. 1.3m, 1.7m C. 1.4m, 1.9m D. 1.9m, 2.5m7. Block A, with a mass of 4 kg, is moving with a speed of 2.0m/s while block B, with a mass of 8 kg, is moving in the opposite direction with a speed of 3m/s. The center of mass of the two block-system is moving with a velocity of:A. 1.3m/s in the same direction as A. B. 1.3m/s in the same direction as B.C. 2.7m/s in the same direction as A. D. 1.0m/s in the same direction as B.8. A large wedge with mass of 10kg rests on a horizontal frictionless surface, as shown. A block with a mass of 5.0kg starts from rest and slides down the inclined surface of the wedge, which is rough. At one instant the vertical component of the blocks velocity is 3.0m/s and the horizontal component is 6.0m/s. At that instant the velocity of the wedge is:A. 3.0m/s to the left B. 3.0m/s to the rightC. 6.0m/s to the right D. 6.0m/s to the left9. A 1.0-kg ball moving at 2.0m/s perpendicular to a wall rebounds from the wall at 1.5m/s. The change in the momentum of the ball is:A. zero B. 0.5N s away from wall C. 0.5N s toward wall D. 3.5N s away from wallII) Fill in the empty space with correct answer1. Two objects, A and B, collide(碰撞). A has a mass of, and B has a mass of . The velocities before the collision arem/s and m/s. After the collision, m/s. The final velocity of B m/s.2. A stream of water impinges on(撞击) a stationary “dished” turbine blade, as shown in Fig.8. The speed of the water is v, both before and after it strikes the curved surface of the blade, and the mass of water striking the blade per unit time is constant at the value . The force exerted by the water on the blade is _.3. A 320g ball with a speed v of 6.22m/s strikes a wall at angle of 30.0o and then rebounds with the same speed and angle. It is in contact with the wall for 10.4 ms. (a) The impulse was experienced by the wall is .(b) The average force exerted by the ball on the wall is .4. The muzzle speed of a bullet can be determined using a device called a ballistic pendulum, shown in Figure. A bullet of mass m moving at speed v encounters a large mass M hanging vertically as a pendulum at rest. The mass M absorbs the bullet. The hanging mass (now consisting of M + m) then swings to some height h above the initial position of the pendulum as shown. The initial speed vof the pendulum (with the embedded bullet) after impact is . The muzzle speed v of the bullet is . III) Calculate Following Problems:1. A block of mass m1=1.60kg initially moving to the right with a speed of 4.00 m/s on a frictionless horizontal track collides with a spring attached to a second block of mass m2=2.10kg initially moving to the left with a speed of 2.50 m/s, as shown in Figure. The spring constant is 600 N/m. (a) At the instant block 1 is moving to the right with a speed of 3.00 m/s, as in Figure, determine the velocity of block 2.(b) Determine the distance the spring is compressed at that instant.2. A 3.00-kg steel ball strikes a wall with a speed of 10.0 m/s at an angle of 60.0 with the surface. It bounces off with the same speed and angle. If the ball is in contact with the wall for 0.200 s, what is the average force exerted on the ball by the wall?3. A small ball with mass m is released from rest at the top of a container which inside wall is semicircle-shaped and frictionless. The container with mass M and radius R rests on a frictionless horizontal surface, as shown. When the ball slides to point B at the bottom of the container, find the normal force exerted by the container on the ball.ABChapter 4 Work and EnergyI) Choose one correct answer among following choices1. The work done by gravity during the descent of a projectile:A. is positive B. is negative C. is zero D. depends for its sign on the direction of the y axis2. A particle has a constant kinetic energy Ek. Which of the following quantities must also be constant? ( )(A) (B) v (C) (D) 3. A 0.2kg block slides(滑行) across a frictionless floor with a speed of 10 m/s. The net work done on the block is ( )(A) -20J (B) -10J (C) 0J (D) 20J4. A 0.50kg object moves in a horizontal circular track with a radius of 2.5m. An external force of 3.0N, always tangent to the track, causes the object to speed up as it goes around. The work done by the external force as the mass makes one revolution is:A. 24 J B. 47 J C. 59 J D. 94 J5. A man pushes an 80-N crate a distance of 5.0m upward along a frictionless slope that makes an angle of 30 with the horizontal. His force is parallel to the slope. If the speed of the crate decreases at a rate of 1.5m/s2, then the work done by the man is:A. 200 J B. 61 J C. 140 J