Physics 2211: Lecture 32

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Physics 2211 Lecture 32
Explosions Inelastic Collisions
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Fireworks Explosions
Fragments tend to fly of in all directions. Why?
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Radioactive Decay of Uranium Nucleus
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Is this a situation where no external forces act
on the system?
No! Gravity acts on every fragment. But,
Conservation of Momentum still applies if we
analyze the problem just before and just after
the explosion, i.e., over a very short time
interval where gravity has little time to act.
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Over a large time interval, gravity reveals its
presence
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Types of Collisions
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Inelastic Collisions
Stick and Slide together
Chalk Time!
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S 3m
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The Throw
The Catch
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While driving on I-285, a bug splatters
inelastically on your windshield. Who
undergoes the greater change in momentum?
1 The bug
2 The car
3 Both the same
4 No enough information given
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Recap
Explosions Inelastic Collisions
Next Lecture
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MomentumProblem 1 The horizontal surface on
which the objects slide is frictionless. If M
2.0 kg and the magnitude of the force of the
small block on the large block is 10 N, determine
F. (a) 15 N (b) 10 N (c) 5 N (d) 20 N (e) 12 N
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Problem 2. A horizontal force of 20 N is exerted
on a 5.0 kg block that slides on a frictionless
horizontal surface. A 2.0 kg block on top of the
5.0 kg block stays fixed with respect to the 5.0
kg block. What force is exerted on the 5.0 kg
block by the 2.0 kg block? (a) (5.7 i19.6 j)
N (b) (-19.6 i 5.7 j) N (c) (19.6 i 19.6 j)
N (d) (-5.7 i 19.6 j)N (e) (5.7 i 19.6 j)
N