Conservation of Momentum Representations Unit 9 Conservation of Momentum Representations

What geometric shape could represent momentum? (p = m*v) How would it change for objects of various masses, velocities and positive and negative directions?

Example 1 A 40 kg girl rollerblades at 4 m/s toward her 20 kg dog, who is running at 7 m/s in the opposite direction. The dog leaps into the girl’s arms and they continue rolling together. Determine their velocity.

object/mass/velocity – + final object/mass/velocity initial event: dog leaps into girls arms(stickie)

object/mass/velocity – + final object/mass/velocity initial event: dog leaps into girls arms(stickie) 40 kg 60 kg 20 kg -7 m/s +4 m/s ? m/s pgi = mgvig = 40 kg*4m/s = 160 kgm/s pdi = mdvid = 20 kg*-7m/s = -140 kgm/s ptotal = 160 kgm/s + -140 kgm/s = 20 kgm/s 60kg * vf

Example 2 A 0.03 kg bullet travelling at 300 m/s ricochets off a 500 kg smart car, in neutral at rest, at 100 m/s in the opposite direction. Determine the momentum transferred to the car.

object/mass/velocity – + final object/mass/velocity initial event: bullet bounces off car (bouncie)

object/mass/velocity – + final object/mass/velocity initial event: : bullet bounces off car (bouncie) 0.03 kg 0.03 kg 500 kg 500 kg 0 m/s +300 m/s -100 m/s ? m/s pbi = mbvib = 0.03 kg*+300m/s = 9 kgm/s pbf = mbvfb = 0.03 kg*+-100m/s = -3 kgm/s pci = mcvic = 500 kg*0m/s = 0 kgm/s pcf = +12 kgm/s ptotal = 9 kgm/s + -0 kgm/s = 9 kgm/s