Ch7_KostmanL

toc Lauren Kostman =Chapter 7: Momentum=

__**Lesson 1a: Momentum**__
What is momentum? - Momentum is "mass in motion" (the quantity of motion an object has). All objects have mass; so if an object is moving, then it has momentum. For example, a sports team that's //on the move// has momentum. - The amount of momentum an object has depends on 1. how much //stuff// is moving (**mass**) and 2. how //fast// the //stuff// is moving (**velocity**). The units are kg*m/s. Momentum= mass * velocity p= m*v - Momentum is a vector quantity (has both magnitude and direction). The direction of the momentum vector is the same as the direction of the velocity vector. - Objects have a large momentum if the mass, velocity, or both are large __**Check Your Understanding:**__ 1.) Determine momentum a. p=(60)*(9)= **540 kg*m/s, east** b. p=(1000)*(20)=**20,000 kg*m/s, north** c. p=(40)(*(2)= **80 kg*m/s, south** 2.) Momentum is 20,000 units; what would be the new momentum if a. p=2(20,000)= **40,000 units** b. p=3(20,000)= **60,000 units** c. p=2(20,000)= **40,000 units** d. p=4(20,000)= **80,000 units** 3.) Compare the velocities of these 3 players. Which player has the greatest momentum? Explain.
 * The tight end goes 2 times the amount of the lineman, but in the same amount of time (he's twice as fast- moves 6m/s.. The halfback goes 3 times as far as the lineman, in the same amount of time, so his velocity is 9 m/s. The halfback and the tight end both have the greatest momentum; each of theirs is 540 kg*m/s, whereas the lineman only has a momentum of 360 kg*m/s.**

__**Lesson 1b:**__
What is the connection between momentum and the impulse connection? - An object with momentum is hard to stop - Impulse is the change in momentum - A rebound is a special type of collision involving a direction change- the result is a large change in velocity

__**Lesson 1c:**__
What are some of the real-world applications? - when objects bounce off each other, this is called rebounding; it involves a change in direction (of an object). - crumple zones on cars are made to reduce the effect of the force (bigger the collision time, less effect of force). - example: mountain climbers use ropes to increase stopping time and decrease effect of the stopping force.

__**Lesson 2d:**__
What equations can be used for algebraic problem soling of momentum conservation in collisions? - Split the collision into "before" and "after" - Solve for the momentum in each (of both objects) and add them up to get the total momentum

__**Lesson 2e:**__
What are momentum conservation in explosions? - In an explosion, an internal impulse acts in order to propel the parts of a system into a variety of directions - After the explosion, the individual parts of the system have momentum