Impulse provides an alternative approach to force problems, especially useful for collisions and variable forces.

Impulse-Momentum Theorem: J = $delta_p$ = $p_{final}$ - $p_{initial}$ = $F_{avg}$ * $delta_t$

Key Concepts:

• Impulse J has the same dimensions as momentum: [$MLT^{-1}$]
• For constant force: J = F * $delta_t$
• For variable force: J = integral of F*dt = area under F-t graph
• Impulse is a vector — direction matters

Bouncing Ball Problems:

• Ball hits wall at v and rebounds at v': J = m(v' - (-v)) = m(v' + v)
• If elastic (v' = v): J = 2mv (maximum impulse)
• If perfectly inelastic (v' = 0): J = mv

Practical Applications:

• Why cricketers "give" with their hands when catching: increases $delta_t$, reduces $F_{avg}$
• Car crumple zones: increase collision time, reduce impact force
• Airbags: same principle — increase $delta_t$ for given $delta_p$