Impulse and Momentum

Student Learning Objectives
Lessons / Lecture Notes
Important Equations
Example Problems
Applets and Animations
Videos

Student Learning Objectives

• To understand the interactions from a new perspective of impulse and momentum.
• To understand and use the impulse-momentum theorem
• To learn what is meant by an isolated system.
• To apply conservation of momentum in simple situations.
• To understand the basic ideas of elastic and inelastic collisions.

Lessons / Lecture Notes

The Physics Classroom (conceptual)

PY105 Notes from Boston University (algebra-based):

Introductory physics notes from University of Winnipeg (algebra-based):

HyperPhysics (calculus-based)

PHY2048 notes from Florida Atlantic University (calculus-based):

PHY2043 notes from Florida Atlantic University (calculus-based)

General Physics I notes from ETSU (calculus-based)

Important Equations

Example Problems

Problem 1
A 1.5 kg ball drops vertically onto a floor, hitting the floor with a speed of 25 m/s.  It is in contact with the floor for 0.020 s and then rebounds to a height of 11.5 m. What is the magnitude of the average force of the floor on the ball? (Solutions)

Problem 2
Two crates are sliding on a frictionless surface as shown in the figure below. The 10 kg crate is sliding to the right at 8.0 m/s and the 25 kg crate is sliding to the left at 5.0 m/s. The two crates collide and stick together. Use conservation of momentum to find the velocity of the two crates after the collision. (Solutions) Applets and Animations
 Baton Throw The Baton Throw model displays a baton thrown up in the air about its center of mass.  The baton is modeled by two masses separated by massless rigid rod.  The path of the center of mass of the baton and the red mass are shown in black and red, respectively. Elastic and Inelastic Collision This Java applet deals with the extreme cases of a collision process illustrated by two wagons: For an elastic collision it is characteristic that the sum of the kinetic energies of the involved bodies is constant. After a perfectly inelastic collision, however, both bodies have the same velocity; the sum of their kinetic energies is reduced, compared with the initial value, because a part of it has changed into internal energy (warming up). Elastic Collision The Elastic Collision Model allows the user to simulate a two-dimensional elastic collision between hard disks. The user can modify the mass, position and velocity of each disk using the sliders.  Both disks are draggable and the center of mass is shown a a cross in the simulation. Collisions on an Air Track Elastic and inelastic collisions on an air track, with different masses for the target cart. Newton's Cradle This applet simulates a well known experiment which demonstrates the conservation of momentum and energy.

Videos

 The Ceter of Mass (COM) of the hammer is marked with a white line (near the head of the hammer). Notice how the COM travels in simple parobolic motion even though the overall motion of the hammer is complicated.