Standard +0.3 This is a straightforward mechanics problem requiring application of Newton's second law or impulse-momentum theorem with constant force. Students need to find constant deceleration from F=ma (a=-6000 m/s²), then use v=u+at to find time. It's slightly above average difficulty due to being Further Maths content and requiring careful handling of signs, but the method is standard with no conceptual challenges.
1 A bullet of mass 0.2 kg is fired into a fixed vertical barrier. It enters the barrier horizontally with speed \(250 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and emerges horizontally after a time \(T\) seconds with speed \(40 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). There is a constant horizontal resisting force of magnitude 1200 N . Find \(T\).
1 A bullet of mass 0.2 kg is fired into a fixed vertical barrier. It enters the barrier horizontally with speed $250 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ and emerges horizontally after a time $T$ seconds with speed $40 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. There is a constant horizontal resisting force of magnitude 1200 N . Find $T$.\\
\hfill \mbox{\textit{CAIE FP2 2019 Q1 [4]}}