Standard +0.3 This is a straightforward projectiles question requiring resolution of velocity components and application of standard kinematic equations. Students must find when the velocity angle equals -40°, which involves setting up tan(40°) = |v_y|/v_x and solving for t. While it requires careful angle work and sign conventions, it's a standard M2 exercise with no novel insight needed—slightly easier than average due to being a single-part calculation.
A particle is projected with speed \(20 \text{ ms}^{-1}\) at an angle of \(60°\) above the horizontal. Calculate the time after projection when the particle is descending at an angle of \(40°\) below the horizontal. [4]
A particle is projected with speed $20 \text{ ms}^{-1}$ at an angle of $60°$ above the horizontal. Calculate the time after projection when the particle is descending at an angle of $40°$ below the horizontal. [4]
\hfill \mbox{\textit{CAIE M2 2017 Q1 [4]}}