Answer
a. The rubber bullet rebounding is more likely to knock the wood over
b. Best: I
Work Step by Step
By Newton's second law, the impulse delivered to an object is equal to the change in its momenta:
$\vec{\mathrm{I}}=\vec{\mathrm{F}}_{\mathrm{a}\mathrm{v}}\Delta t=\Delta\vec{\mathrm{p}}\qquad$ 9-6
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a.
Observing the change in momentum of the bullet, the wood delivers less impulse to the bullet if the speed of the bullet after the collision is zero than if the bullet has speed (after rebounding).
Since the wood delivers more impulse to the bullet, the bullet, in reaction, delivers more impulse to the wood in the case of rebounding.
b.
I is true.
II is true, but has no bearing on the wood being knocked over.
III is false, according to part a.
Best: I
