A-LevelMathematicsMechanics9709/42 · Oct/Nov 2021 · Q35 Marks
The diagram shows a semi-circular track ABC of radius 1.8 m which is fixed in a vertical plane. The points A and C are at the same horizontal level and the point B is at the bottom of the track. The section AB is smooth and the section BC is rough. A small block is released from rest at A. [Diagram]
- (a)Show that the speed of the block at B is 6 ms⁻¹.[2]
- (b)The block comes to instantaneous rest for the first time at a height of 1.2 m above the level of B. The work done against the resistance force during the motion of the block from B to this point is 4.5 J. Find the mass of the block.[3]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.
- M1 Use of conservation of energy, 2 terms. Must NOT use constant acceleration equations. Use of equations such as v² = u² + 2as scores M0 A0.
- A1 AG Speed of block at B = v = 6 ms⁻¹
- M1 Attempt the work-energy equation. In the form: ± KE lost = ± PE gain ± WD against Resistance. If using motion from A to final point, mg × 1.8 = mg × 1.2 + 4.5
- A1 Mass of the block = m = 0.75 kg
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →