Moderate -0.5 This is a straightforward application of the impulse-momentum theorem with constant force. Students need to apply F×t = m(v-u) with all values given directly, requiring only algebraic rearrangement to find m. While it involves mechanics rather than pure maths, the single-step calculation and direct substitution make it easier than average A-level questions.
1 A bullet of mass \(m \mathrm {~kg}\) is fired into a fixed vertical barrier. It enters the barrier horizontally with speed \(280 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and emerges horizontally after 0.01 s with speed \(30 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). There is a constant horizontal resisting force of magnitude 1500 N . Find \(m\).
1 A bullet of mass $m \mathrm {~kg}$ is fired into a fixed vertical barrier. It enters the barrier horizontally with speed $280 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ and emerges horizontally after 0.01 s with speed $30 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. There is a constant horizontal resisting force of magnitude 1500 N . Find $m$.
\hfill \mbox{\textit{CAIE FP2 2013 Q1 [4]}}