Moderate -0.3 This is a straightforward application of the impulse-momentum theorem using vector triangles. Students need to recognize that momentum before, impulse, and momentum after form a triangle, then apply the cosine rule - a standard M3 technique with clear setup and routine calculation. The 6 marks reflect multiple steps rather than conceptual difficulty.
A small ball of mass \(0.8\) kg is moving with speed \(10.5\) m s\(^{-1}\) when it receives an impulse of magnitude \(4\) N s. The speed of the ball immediately afterwards is \(8.5\) m s\(^{-1}\). The angle between the directions of motion before and after the impulse acts is \(\alpha\). Using an impulse-momentum triangle, or otherwise, find \(\alpha\). [6]
A small ball of mass $0.8$ kg is moving with speed $10.5$ m s$^{-1}$ when it receives an impulse of magnitude $4$ N s. The speed of the ball immediately afterwards is $8.5$ m s$^{-1}$. The angle between the directions of motion before and after the impulse acts is $\alpha$. Using an impulse-momentum triangle, or otherwise, find $\alpha$. [6]
\hfill \mbox{\textit{OCR M3 2010 Q1 [6]}}