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Browsing Animations: Momentum, Collisions, KE
11 Animations
collision-elastic-2.iwp
Two gliders collide in an elastic collision. The red glider is initially stationary. The x-coordinate of the center of mass of the system of gliders is shown as a black dot. Play the animation. Click Show Graph. The velocities of the two objects and of the center of mass will be displayed as a function of time. Try collisions for different values of mass and initial velocity. After a while, you should be able to predict the final velocities, given any pair of initial velocities.
collision-elastic-4.iwp
What is the total momentum of this system? Why can't you use the law of conservation of momentum to calculate what the velocities of both objects after the collision are? There is nevertheless a way to predict the final velocities. Examine the velocity vs. time graphs. Make changes to a mass or an initial velocity and run the collision. Examine the velocity vs. time graphs again. Continue making changes and examining the graphs. Look for a pattern that will allow you to predict the final velocities without running the animation.
collision-inelastic-01a.iwp
Answer these questions using the animation. The grid spacing in meters is given in the upper right, and the elapsed time and masses of the objects are given under Outputs. 1. What is the velocity before collision of the blue block? 2. What is the velocity after collision of the combined blocks? 3. What is the product of mass and velocity of the blue block before collision? (This is called the initial momentum of the blue block.) 4. What is the product of mass and velocity of the combined blocks after collision? (This is called the final momentum of the combined blocks.) 5. How do your answers to 3 and 4 compare? 6. On one set of axes, sketch velocity vs. time graphs for the red and blue blocks from t = 0 to 5 s. Use a different color for the lines for the two blocks.
collision-inelastic-01b.iwp
Check your answers. Velocities and momenta are given under inputs and outputs. Click on Show Graph for velocity vs. time graphs.
collision-inelastic-02a.iwp
Two objects collide and stick together. The animation stops as the collision starts. You are to predict the velocity after collision of the combined blocks. Use the fact that the total momentum is conserved. This means that the sum of the momenta of the blocks before the collision is equal to the sum of the momenta after the collision. Also sketch the velocity vs. time graph for the objects as you did in the previous problem.
collision-inelastic-02b.iwp
Check your answers. Velocities and momenta are given under inputs and outputs. Click on Show Graph for velocity vs. time graphs.
collision-inelastic-03a.iwp
Two objects collide and stick together. The animation stops as the collision starts. Use conservation of momentum to predict the velocity after collision of the combined blocks. Also sketch the velocity vs. time graph for the objects.
collision-symmetric.iwp
Two gliders of equal mass collide in an elastic collision. Play the animation. Click Show Graph. The velocities of the two objects will be displayed as a function of time. Try collisions for different pairs of initial velocities. After a while, you should be able to predict the final velocities, given any pair of initial velocities.
finalke-03.iwp
1. Two dimunitive cars, initially at rest, are subjected at t =0 to an identical and constant force in the +x direction. How do the kinetic energies (see outputs) of the two cars compare after traveling the same distance? Does your answer depend on the masses of the cars? the applied force? the position of the finish line? 2. How do the kinetic energies of the two cars compare after traveling for the same amount of time? Does your answer depend on the masses of the cars? the applied force?