Gravity and motion — Question 246

ANSWER

(a) Velocity points up-right at A, right at B and down-right at C. Acceleration is vertically downward at all three. (b) $8.00\,\mathrm{m\,s^{-1}}$.

Worked solution

(a) Horizontal velocity is always $8.00\,\mathrm{m\,s^{-1}}$. The vertical velocity is positive at A, zero at B and negative at C. Gravity acts downward throughout, including at the apex.

(b) At the apex $v_y=0$, so $v=|v_x|=8.00\,\mathrm{m\,s^{-1}}$.

Equivalent physically justified methods, alternative valid sketches and consistent units accepted.

Accept sensible significant figures and consistent rounding from stated constants.

Part a: Draw the up-right and down-right tangent velocity arrows at A and C.

[1 mark]

Part a: Draw a nonzero horizontal velocity at B.

[1 mark]

Part a: Draw downward acceleration arrows at all three points.

[1 mark]

Part b: Give the nonzero apex speed.

[1 mark]

Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.