Resource Lesson
Momentum and Energy
Printer Friendly Version
The relationship between conservation of energy and conservation of momentum is an extremely important one.
During every collision, momentum is conserved.
Remember that conservation of momentum is actually a restatement of Newton's Third Law.
Occasionally kinetic energy is also conserved during an
elastic collision
. When this type of collision is being references problems will explicitly state that a steel ball or a "superball" bounces elastically off a surface. The implication is that the ball will return to the same height from which it is released. That is, its original gravitational potential energy is transformed into kinetic energy which remains constant throughout the collision allowing the ball to return to its original height. Those collisions are rare and far between.
But even when collisions lose KE, and are considered to be
inelastic
, we often use conservation of energy methods to analyze the behaviors of the objects involved. We do this by considering the energy content of the system before the objects collide and then again after they collide - just NOT during the collision. Given below are some classic examples.
Refer to the following information for the next two questions.
[
ballistic pendulum
] A 10-gram bullet is fired from a rifle at a speed of 700 m/sec into a 1.50-kg wooden block suspended by a string that is two meters long.
After the collision, through what vertical distance (h) does the block rise?
How much KE is lost during the collision?
Refer to the following information for the next question.
[
table projectile
] A block having a mass of 800 grams is at rest near the edge of a frictionless table. A second block, of mass 600 grams, is sliding towards it at a speed of 4 m/sec.
If the table is 1 meter above the floor, and the blocks stick together after the collision, how far from the end of the table will they strike the floor?
Refer to the following information for the next two questions.
[
impact collision
] A block having a mass of 600 grams is sliding towards the edge of a frictionless table at a speed of 4 m/sec. On the floor, at the base of the table is a 200 gram cart, initially at rest. The table is 1 meter above the floor.
How far from the base of the table should the cart be placed?
If the block sticks to the cart after the collision, how fast will the block-cart combination begin to move across the floor?
Refer to the following information for the next question.
[
skid marks
] A 2000-kg car moving with an unknown speed strikes a 1000-kg car that is initially at rest. After the collision, the two cars stick together and skid to a stop on asphalt, where the friction coefficient is 0.65. The police measure the skid marks to be 40 meters long.
Determine the speed of the 2000-kg car just before the collision.
Related Documents
Lab:
Labs -
A Battering Ram
Labs -
A Photoelectric Effect Analogy
Labs -
Air Track Collisions
Labs -
Ballistic Pendulum
Labs -
Ballistic Pendulum: Muzzle Velocity
Labs -
Bouncing Steel Spheres
Labs -
Collision Pendulum: Muzzle Velocity
Labs -
Conservation of Energy and Vertical Circles
Labs -
Conservation of Momentum
Labs -
Conservation of Momentum in Two-Dimensions
Labs -
Impulse
Labs -
Inelastic Collision - Velocity of a Softball
Labs -
Loop-the-Loop
Labs -
Ramps: Sliding vs Rolling
Labs -
Roller Coaster, Projectile Motion, and Energy
Labs -
Rotational Inertia
Labs -
Rube Goldberg Challenge
Labs -
Spring Carts
Labs -
Target Lab: Ball Bearing Rolling Down an Inclined Plane
Labs -
Video LAB: Ball Re-Bounding From a Wall
Labs -
Video Lab: Blowdart Colliding with Cart
Labs -
Video Lab: Cart Push #2 and #3
Labs -
Video LAB: Circular Motion
Labs -
Video Lab: M&M Collides with Pop Can
Labs -
Video Lab: Marble Collides with Ballistic Pendulum
Resource Lesson:
RL -
A Further Look at Impulse
RL -
APC: Work Notation
RL -
Conservation of Energy and Springs
RL -
Energy Conservation in Simple Pendulums
RL -
Famous Discoveries: The Franck-Hertz Experiment
RL -
Gravitational Energy Wells
RL -
Linear Momentum
RL -
Mechanical Energy
RL -
Potential Energy Functions
RL -
Principal of Least Action
RL -
Rotational Dynamics: Pivoting Rods
RL -
Rotational Kinetic Energy
RL -
Springs and Blocks
RL -
Symmetries in Physics
RL -
Tension Cases: Four Special Situations
RL -
Work
RL -
Work and Energy
Worksheet:
APP -
Puppy Love
APP -
The Jogger
APP -
The Pepsi Challenge
APP -
The Pet Rock
APP -
The Pool Game
APP -
The Raft
CP -
Conservation of Energy
CP -
Conservation of Momentum
CP -
Momentum
CP -
Momentum and Energy
CP -
Momentum and Kinetic Energy
CP -
Momentum Practice Problems
CP -
Momentum Systems and Conservation
CP -
Power Production
CP -
Satellites: Circular and Elliptical
CP -
Work and Energy
NT -
Cliffs
NT -
Elliptical Orbits
NT -
Escape Velocity
NT -
Gravitation #2
NT -
Ice Boat
NT -
Momentum
NT -
Ramps
NT -
Satellite Positions
WS -
Advanced Properties of Freely Falling Bodies #1
WS -
Advanced Properties of Freely Falling Bodies #2
WS -
Advanced Properties of Freely Falling Bodies #3
WS -
Charged Projectiles in Uniform Electric Fields
WS -
Energy Methods: More Practice with Projectiles
WS -
Energy Methods: Projectiles
WS -
Energy/Work Vocabulary
WS -
Force vs Displacement Graphs
WS -
Introduction to Springs
WS -
Kinematics Along With Work/Energy
WS -
Potential Energy Functions
WS -
Practice: Momentum and Energy #1
WS -
Practice: Momentum and Energy #2
WS -
Practice: Vertical Circular Motion
WS -
Rotational Kinetic Energy
WS -
Static Springs: The Basics
WS -
Work and Energy Practice: An Assortment of Situations
WS -
Work and Energy Practice: Forces at Angles
TB -
Work, Power, Kinetic Energy
PhysicsLAB
Copyright © 1997-2019
Catharine H. Colwell
All rights reserved.
Application Programmer
Mark Acton