Unit 5
Unit 6
Unit 7
Unit 8
100
Two objects of the same mass travel in opposite directions along a horizontal surface. Object X has a speed of 5ms and object Y has a speed of 5ms, as shown in the figure. After a period of time, object X collides with object Y. In scenario 1, the objects stick together after the collision. In scenario 2, the objects do not stick together after the collision.
Consider scenario 1. Is the object X–object Y system open or closed? Predict whether both the momentum and the kinetic energy of the system will be the same or different after the collision.
Type of System - Closed
Momentum - Same
Kinetic Energy - Changes
100
A student attaches a 0.6kg block to a vertical spring so that the block-spring system will oscillate if the block-spring system released from rest at a vertical position that is not the system’s equilibrium position. The student measures the velocity of the block as a function of time as the system oscillates, as shown in the graph. The spring constant of the spring is most nearly....
2.6 N/m
100
An object of mass M hangs from a string that is looped around a pulley of negligible friction, as shown. The pulley has a mass 0.5M. The object is released from rest and it falls to the floor at time t1. Draw a graph to represent the angular speed as a function of time for the pulley.
100
A fluid has a density p1 and is used to fill a rectangular swimming pool that has surface area A1 and depth d1. The same fluid is going to be used to fill a larger pool with surface area 2A1 and depth 2d1. How will the mass m2 of fluid in the larger pool compare to the mass m1 of the fluid in the smaller pool?
m2 = 4m1
200
A student conducts an experiment in which a cart is pulled by a variable applied force during a 2 s time interval. In trial 1, the student exerts the force on a cart of mass M. In trial 2, the student exerts the force on a cart of mass 3M. In trial 3, the student exerts the force on a cart of 5M. In which trial will the cart experience the greatest change in momentum from 0 s to 2 s?
All changes are equal
200
Student X attaches an object of mass M to the end of a string of length L so that a pendulum is constructed. Student Y attaches an object of mass M to a string of length 4L to construct a second pendulum. How does the period of these two pendulums compare?
X is half of Y
200
A rod is initially at rest on a rough horizontal surface. Three forces are exerted on the rod with the magnitudes and directions shown in the figure. The force exerted in the center of the rod is an equidistant 0.5m from both ends of the rod. If friction between the rod and the table prevents the rod from rotating, what is the magnitude of the torque exerted on the rod about its center from frictional forces?
20 Nm
200
The weather balloon shown in the figure has a volume 120 m3 of and is filled with a gas of density 0.19 kg/m3. The volume of the balloon material is negligible. The mass of the balloon, not including the gas, is 50kg. The balloon is attached to the ground by a cable. The air surrounding the balloon has a density of 1.2 kg/m3. The tension in the cable is most nearly
712 N
300
Block X travels towards Block Y that is initially at rest, as shown in the figure, and eventually collides with Block Y. Which of the following diagrams represents the final velocities for Block X and Block Y after the collision if the collision is elastic?
300
A block on a horizontal surface is attached to a horizontal spring of negligible mass and spring constant 30N/m. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. The block-spring system experiences simple harmonic motion, as shown in the graph.
What is the change in spring potential energy of the block-spring system from when the block is released to when the block has its greatest speed?
240 J
300
A rod may freely rotate about an axis that is perpendicular to the rod and is along the plane of the page. The rod is divided into four sections of equal length of 0.2m each, and four forces are exerted on the rod, as shown in the figure. Frictional forces are considered to be negligible. Which of the following correctly describes an additional torque that must be applied in order to keep the rod from rotating?
18Nm counterclockwise
300
A uniform rod is placed with its center of mass on a support. A cylindrical bucket is hung at a distance d1 to the left of the rod’s center and a liquid of density p1 is poured into the bucket up to a height h1. On the right side, another cylindrical bucket is hung at a distance d2 to the right of the rod’s center and a different liquid of density p2 is poured into the bucket up to a height h2. The buckets each have radius r and their masses are negligible. If the rod-buckets system is in equilibrium, what is the density p2 of the fluid in the bucket on the right?
p1h1d1/h2d2
400
Block X and block Y travel toward each other along a horizontal surface with block X traveling in the positive direction. Block X has a mass of 2kg and a speed of 3m/s. Block Y has a mass of 1kg and a speed of 3m/s. After the collision, block X travels in the horizontal direction with a speed of 1m/s in the negative direction. What is the speed of block Y if the collision is elastic?
5 m/s
400
A block of mass M hangs at rest at the bottom of a stationary spring that stretches a distance A from the spring’s unstretched length. The block is then pulled down an additional distance A so the spring is stretched a distance 2A , as shown in the figure. The block is released from rest, and the center of mass of the block vertically oscillates a displacement of 2A from its lowest position to its highest position. The lowest vertical position of the block’s center of mass is the location at which the gravitational potential energy of the block-spring-Earth system is zero. Where is kinetic energy at its maximum?
KE is max at A
400
During an experiment, students collect data about the angular momentum of a rigid, uniform spinning wheel about an axle as a function of time, which was used to create the graph that is shown. A frictional torque is exerted on the wheel. A student makes the following statement about the data.
“The frictional torque exerted on the wheel is independent of the wheel’s angular speed.”
Does the data from the graph support the student’s statement? Why or why not?
Yes, because the slope of the line is constant.
400
At the instant shown in the figure, Block 1 and Block 2 are both completely submerged in a liquid. The center of Block 1 is a distance d below the surface of the water, and the center of Block 2 is a distance 3d below the surface. The mass of Block 1 is m and the mass of Block 2 is 2m. The blocks have the same volume. The buoyant force on Block 1 is Fb1 and the buoyant force on Block 2 is Fb2. What is the ratio Fb1:Fb2?
1:1
500
An object travels in the positive direction with a momentum of 5 kg⋅ms . An applied force is exerted on the object, and a graph of the magnitude of the applied force as a function of time is shown. All frictional forces are considered to be negligible. Which of the following could represent the approximate momentum of the object after the force has been applied? Select two answers.
3 kgm/s
7 kgm/s
500
A group of students must study the oscillatory motion of a pendulum. One end of a light string is attached to the ceiling, and the other end of the string is attached to a mass hanger so that small disks of various masses may be stacked on the hanger, as shown in the figure.
Question
Students are provided with data in which an experiment was conducted to determine the relationship between the length of the pendulum and the period of oscillation. The data include a pendulum of length 0.5m, for which it took 81 s for the pendulum bob to oscillate 10 times. However, the experiment was conducted at a location that is not near Earth’s surface. The gravitational field strength where the experiment was conducted is most nearly
0.30 N/kg
500
A disk rotates about its center with an angular speed of 30 rad/s. An identical disk is held at rest above the rotating disk and is then gently dropped on the rotating disk, as shown in Figure 1. The two-disk system then rotates with a common angular speed ω1. A third identical disk is held at rest above the two-disk system. The third disk is gently dropped on the rotating two-disk system, as shown in Figure 2. The three-disk system then rotates with a common angular speed ω2. What is value of ω2?
10 rad/s
500
Cylinders 1 and 2 are identical hollow containers. Equal volumes of five different liquids, A, B, C, D, and E, are poured into Cylinder 1. The liquids separate, forming five distinct layers, as shown in the figure. Cylinder 2 is filled with the same total volume of liquid as Cylinder 1, but with only liquid C. A student claims the pressure at the bottom of Cylinder 1 must be equal to the pressure at the bottom of Cylinder 2. Is the student’s claim correct? Why or why not?
No, because the pressure at the bottom of the two columns of liquid cannot be compared without knowing the relative values of the densities of the individual fluids.