IWP Applets for Chapter 8
|
ID/Type |
Web Link or WA Question Code |
Local download |
Launch from browser |
Description |
|
G8-5a |
Using Wext = DEsys
when Wext does not Equal Zero |
energy-fall-01.iwp |
energy-fall-01.iwp |
A ball is tossed upward in the absence of air friction. The situation depicted is for times after the upward push force is no longer acting on the ball. The vector shown represents the velocity of the ball.
The 0 level for gravitational potential energy is taken to be the initial position of the ball. The system is taken to be the ball, the Earth, and the gravitational force. The values of kinetic energy, gravitational potential energy, and energy of the system are shown by the vertical, colored bars. |
|
G8-5a |
Using Wext = DEsys
when Wext does not Equal Zero |
energy-fall-02.iwp |
energy-fall-02.iwp |
A ball is tossed upward in the absence of air friction. The situation depicted is for times after the upward push force is no longer acting on the ball. The vector shown represents the velocity of the ball.
The 0 level for gravitational potential energy is taken to be the highest position of the ball. The system is taken to be the ball, the Earth, and the gravitational force. The values of kinetic energy, gravitational potential energy, and energy of the system are shown by the vertical, colored bars.
|
|
G8-5a |
Using Wext = DEsys
when Wext does not Equal Zero |
energy-fall-03.iwp |
energy-fall-03.iwp |
A block is given an initial velocity upward. The vector shown represents the velocity of the ball. After t = 0, the forces acting on the block are gravity and the kinetic friction forces exerted by the rails on the block. Note that the friction force is down--in the direction of gravity--when the block is on the way up. On the way down, the friction force switches directions. Hence, the block experiences different accelerations on the way up and way down. However, these accelerations need not be known in order to do an energy analysis. (Continue reading below.) The 0 level for gravitational potential energy is taken to be the initial position of the ball. The system is taken to be the ball, the Earth, and the gravitational force. Friction is an external force that does negative work on the system. The values of kinetic energy, gravitational potential energy, energy of the system, and work done by friction are shown by the vertical, colored bars. (The jitter on the E = 0 line is a result in small errors in the way the applet updates position and velocity values used in calculating energies.) |
|
G8-5a |
Using Wext = DEsys
when Wext does not Equal Zero |
energy-fall-04.iwp |
energy-fall-04.iwp |
A block is given an initial velocity upward. The vector shown represents the velocity of the ball. After t = 0, the forces acting on the block are gravity and the kinetic friction forces exerted by the rails on the block.
The 0 level for gravitational potential energy is taken to be the initial position of the block. The system is taken to be the ball, the Earth, the gravitational force, the rails, and the friction force. The values of kinetic energy, gravitational potential energy, thermal energy, and energy of the system are shown by the vertical, colored bars. |
|
E.08.01v2 |
APB-08-01-16 |
spring_work-04.iwp |
spring_work-04.iwp |
A block slides frictionlessly toward a relaxed spring. As the block compresses the spring, the spring does work on the block. A vector representing the spring force is shown as well as a graph of the spring force vs. position. The yellow area under the line is the work done by the spring force. |
|
E.08.01v2 |
APB-08-01-17 |
spring_work-04.iwp |
spring_work-04.iwp |
A block slides frictionlessly toward a relaxed spring. As the block compresses the spring, the spring does work on the block. A vector representing the spring force is shown as well as a graph of the spring force vs. position. The yellow area under the line is the work done by the spring force. |
|
E.08.03v3 |
APB-08-03-01t |
spring_work-03.iwp |
spring_work-03.iwp |
A block slides frictionlessly toward a relaxed spring. As the block compresses the spring, the spring does work on the block, bringing it to a stop. Determine the spring constant of the spring.
Caution: Unphysical results (such as the block passing through the wall) may be result from some combinations of initial velocity and mass. In such cases, one simply imagines that the spring and support extend further to the right. The block will always return, given enough time. |
|
E.08.05 |
APB-08-05-02 |
energy-spring-1b.iwp |
energy-spring-1b.iwp |
When you play the animation, the block oscillates horizontally about the origin on a frictionless table. The origin is in the center and the direction of +x is to the right. The oscillation is the result of a Hooke's Law force applied by the spring to the block. The system is taken to be the block, spring, and spring force. (Gravitational and normal forces do no work on the block.)
Which one of the energy bar diagrams (A,B,C,D) represents how the kinetic energy (blue), elastic potential energy (red), and total system energy (green) change as a function of time? |
|
E.08.05 |
APB-08-05-05 |
energy-vertspring-01.iwp |
energy-vertspring-01.iwp |
A block is suspended from a fixed support by a rubber band. When held in place by the green stick, the rubber band is completely relaxed. When the green stick is pulled away, the block oscillates vertically under the action of gravity and a Hooke's Law type spring force. The red line (marked y = 0) is the position at which both gravitational and elastic potential energy are taken to be 0. The system includes the block, Earth, band, gravity, and spring force. No external forces act on the system.
When you play the animation, 4 sets of blue, red, and green bars labeled A-D will appear. One of these sets represents the kinetic (blue), elastic potential (red), and gravitational potential (green) energies. Which set is the correct one? (Note the indicator of positive, 0, and negative energy shown to middle left.) |
|
E.08.05 |
APB-08-05-01 |
energy-plane-03.iwp |
energy-plane-03.iwp |
A block is initially given a push to start it moving up a inclined plane. At t = 0, the push is removed. The 0 level for gravitational potential energy is taken to be the initial vertical position of the block. The system is taken to be the block, the Earth, and the gravitational force. The external normal force of the plane on the block does no work, since the force and displacement are always perpendicular. The external force of kinetic friction does negative work on the block, since the friction force is always opposite the displacement. The values of kinetic energy, gravitational potential energy, energy of the system, and work due to friction are shown by the vertical, colored bars. |
|
E.08.05 |
APB-08-05-03 |
energy-spring-2b.iwp |
energy-spring-2b.iwp |
A block oscillates horizontally about the origin. There is kinetic friction between the block and the table. The origin is in the center, the direction of +x is to the right, and the grid spacing is 0.01 m. The heights of the vertical bars shown below the table are proportional to the values of kinetic energy (K), elastic potential energy (Ue), thermal energy (T), and total energy of the system (Esys). The system includes the block, spring, table, spring force, and friction force. |
|
E.08.05 |
APB-08-05-04 |
energy-spring-2c.iwp |
energy-spring-2c.iwp |
A block oscillates horizontally about the origin on a frictionless table. Determine the magnitude of the initial velocity of the block, |
|