Moderate -0.3 This is a straightforward application of the work-energy principle with a constant force. Students need to convert units (grams to kg, cm to m), calculate the change in kinetic energy, and equate it to work done. While it requires careful unit conversion and multi-step calculation, it's a standard M2 question with no conceptual difficulty—just direct application of W = ΔKE with given values.
2. A bullet of mass 6 grams passes horizontally through a fixed, vertical board. After the bullet has travelled 2 cm through the board its speed is reduced from \(400 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) to \(250 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). The board exerts a constant resistive force on the bullet.
Find, to 3 significant figures, the magnitude of this resistive force.
(5)
2. A bullet of mass 6 grams passes horizontally through a fixed, vertical board. After the bullet has travelled 2 cm through the board its speed is reduced from $400 \mathrm {~m} \mathrm {~s} ^ { - 1 }$ to $250 \mathrm {~m} \mathrm {~s} ^ { - 1 }$. The board exerts a constant resistive force on the bullet.
Find, to 3 significant figures, the magnitude of this resistive force.\\
(5)\\
\hfill \mbox{\textit{Edexcel M2 Q2 [5]}}