How much does a triangular force pulse change velocity?

A 0.5 kg cart moves right at 2 m/s on a horizontal rail. A rightward net force rises linearly from zero at t = 0 to 6 N at t = 0.2 s, then falls linearly to zero at t = 0.4 s.

The force varies with time. The shaded area represents impulse.

What is the cart’s velocity immediately after the pulse?

Organize the givens & assumptions

Mass: 0.5 kg
Initial velocity: +2 m/s
Force pulse: triangle, base 0.4 s, height 6 N

The specified force is the net horizontal force. Mass is constant. Use right as positive.

A $2.4\ \mathrm{m\,s^{-1}}$
B $4.4\ \mathrm{m\,s^{-1}}\ \text{right}$
C $6.8\ \mathrm{m\,s^{-1}}$
D $1.2\ \mathrm{m\,s^{-1}}$

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