Momentum/Impulse

Momentum Recap

• Momentum: The product of the mass and velocity of an object▫ “How hard it is to stop something”

• Equation: p = mv

• Units: p = kgm/s m = kg v = m/s

• Vector: When describing the momentum of an object, the direction matters.

Momentum Recap

Would you rather

• Would you rather?

1 m/s 100 m/shttp://www.youtube.com/watch?v=JK81Ej5hm8s

http://www.youtube.com/watch?v=iMq0Wyl-3ho

• Would you rather?

10 m/s 10 m/s

• Would you rather?

100 m/s 5 m/s

Momentum Recap

• Collision: When 2 objects interact and “exchange” momentum

• 2 Moving (Bounce off)• 1 Moving (bounce off)• 1 moving (stick together)• “Explosion

Momentum Recap

• Conservation of Momentum: The sum of the total momentum BEFORE a collision, is the same as the sum of the total momentum AFTER a collision

Momentum Before = Momentum After

pi = pf

p1i +p2i + p3i = p1f+p2f + p3f

Momentum Recap

• Conservation of Momentum: The sum of the total momentum BEFORE a collision, is the same as the sum of the total momentum AFTER a collision

Real Deal

•Step 1: Separate BEFORE and AFTER

•Step 2: Make a table (p,m,v) for each object

•Step 3: Eqtn to sum up total momentum BEFORE

•Step 4: Eqtn to sum up total momentum AFTER

•Step 5: Set the equations equal to each other.

Impulse

•IMPULSE: A change in momentum

Fnett = p = mv

Units = Ns

Whiteboards

Impulse

Super Challenge: I = Ft