O-LevelPhysicsKinematics5054/21 · Oct/Nov 2014 · Q18 Marks

Fig. 1.1 shows a motorcycle during a race. [Figure 1.1] The motorcycle accelerates along a straight section of the track from a speed of 40m/s to maximum speed. Fig. 1.2 is the speed-time graph for the motorcycle along the straight section of the track. [Figure 1.2] The mass of the motorcycle is 180 kg.

(a)(i)For the time 0 to 2.0s, determine the acceleration of the motorcycle,[2]
(a)(ii)the resultant force acting on the motorcycle.[2]
(b)(i)The driving force acting on the motorcycle remains constant throughout the 12s spent on the straight section of track. Using Fig. 1.2, describe how the acceleration of the motorcycle changes during this time.[1]
(b)(ii)Explain, in terms of the forces acting, why the acceleration changes in this way.[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 2014). The mark or mark type is shown in brackets.

[2] (a) (i) (a =) (v−u)/t or ∆v/t or (55–40)/2 or equivalent values from graph
7.5m/s²
[2] (a) (ii) (F = ) ma or 180 × 7.5
1300/1350/1400 N
[1] (b) (i) (acceleration) decreases (to zero)
[3] (b) (ii) air resistance/friction/drag mentioned
air resistance/friction/drag increases (with speed) or resultant force decreases (with speed)
(finally) (air) resistance = driving force or resultant is zero

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.