Transcript Interactions and momentum

Interactions
Impulse and Momentum
Exchange
Main ideas…
• Vector representation of velocity
• How impulse relates to change in
momentum
• How impulse relates to force
• Graphical representation of impulse
• Newton’s 2nd Law
• Working with the “multi-tap” interaction
model
C3.1 Vector representation of
velocity
• A bird at r1(23, 15, 30) m moves to r2(16,
35, 40) m in Dt = 2.3 s
– Try to sketch this!
– Find the average velocity in component form
– Find the magnitude of the average velocity
C3.2 Interaction and Momentum
Transfer
– If the bird in the previous example has a mass
of 0.200 kg what is its momentum?
– If a force of F=(5,1,0) N acted for 2 s how
would the interaction change the momentum
of the bird?
– Do we have enough information to tell us the
final direction of motion of the bird?
Momentum-transfer principle:
any interaction between bodies involves a transfer of momentum
C3.5 The Multi-tap model and
Trajectories
– Create a 3D grid in which the z-axis is out of the page
(VPython friendly!)
– Give a 1.0 kg ball an initial velocity of vi(30,60,0) m/s;
what is pi?
– Let Fgravity = (0, -10, 0) m/s/s in this frame
– Sketch a momentum vector for the ball at Dt = 1,2,3
etc s intervals.
– When is the ball at the top of its trajectory. How do
you know?
– Explain to your partner how you could use this to
approximate the path of the ball.