Force and Potential Energy 3 D Energy Diagram

Force and Potential Energy (3 D) •

Energy Diagram • We can glean a lot of information by looking at graph of the potential energy.

Energy Diagram Example

Chapter 7 Summary Potential Energy and Energy Conservation •

Chapter 8 Outline Momentum, Impulse, and Collisions • Momentum • Impulse • Conservation of momentum • Vector components • Collisions • Elastic and inelastic • Center of mass • Rocket propulsion

Momentum • Consider the case of a collision between two cars. • Using Newton’s laws to find the resulting motion is difficult. • We do not fully know the exact forces involved. • We can deal with situations such as these by considering a new concept, momentum.

Momentum •

Impulse-Momentum Theorem •

Impulse •

Impulse Example

Conservation of Momentum •

Conservation of Momentum •

Conservation of Momentum Example

Types of Collisions • We define a collision to be any strong interaction between bodies that lasts for a relatively short time. • In an elastic collision, all of the forces between the colliding bodies are conservative, no mechanical energy is lost and the total kinetic energy is the same before and after. • In an inelastic collision, the internal forces are not all conservative, the total kinetic after the collision is less than before. • If the bodies stick together after the collision, it is a completely, or perfectly inelastic collision. • Regardless, momentum is conserved!

Collision Example

Elastic Collisions in One Dimension •

Collision Example #2