http://www.ck12.org Chapter 7. Momentum
CHAPTER
7 Momentum
Chapter Outline
7.1 Momentum and Impulse
7.2 CONSERVATION OFMOMENTUM INONEDIMENSION
7.3 CONSERVATION OFMOMENTUM INTWODIMENSIONS
7.4 REFERENCES
We use the terms “momentum” and “impulse” in daily life, but they have more specific meanings when used in
physics. Nonetheless, we can understand the ideas without proper definitions. If a speeding car comes to a rapid
stop, we understand that the people in the car have a forward momentum: after the car stops, they continue to go
forward. We usually use the word “impact” to refer to a result: cars have a negative impact on the environment,
airbags can impact us by saving our lives. In physics, however, “impact” refers to the time over which a force is
applied. Airbags do save lives, but they do so by reducing the impact of the passenger hitting the wheel or dash, by
increasing the time over which the force of the crash affects the passenger.