Date | November 2010 | Marks available | 1 | Reference code | 10N.2.SL.TZ0.A2 |
Level | Standard level | Paper | Paper 2 | Time zone | Time zone 0 |
Command term | Calculate | Question number | A2 | Adapted from | N/A |
Question
In 1997 a high-speed car of mass \(1.1 \times {10^4}{\text{ kg}}\) achieved the world land speed record. The car accelerated uniformly in two stages as shown in the table. The car started from rest.
Use the data to calculate the
average acceleration of the car in stage 1.
average net force required to accelerate the car in stage 2.
total distance travelled by the car in 12 s.
Markscheme
\(11{\text{ m}}{{\text{s}}^{ - 2}}\);
\(\Delta v = 236\);
\(a = \left( {\frac{{236}}{8} = } \right){\text{ }}29.5{\text{ }}\left( {{\text{m}}\,{{\text{s}}^{ - 2}}} \right)\);
\((F = 1.1 \times {10^4} \times 29.5) = 3.2 \times {10^5}{\text{ N}}\);
Award [2 max] for omission of initial speed (answer is 390 kN).
Award [3] for correct bald answer.
phase 1 distance 88 m / phase 2 distance 1296 m;
total 1400 m;
Award [2] for correct bald answer.
Watch for significant figure penalty in this question (1384 m).
Award [1 max] for \(\frac{1}{2}\)at2 substituted correctly for first phase, if no distances
evaluated and answer incorrect.
Award [1 max] for correct addition of incorrect phase 1 and/or 2 distance(s).
Examiners report
Most candidates were able to score well on this part.
There were widespread failures to achieve the correct intermediate step of evaluating the acceleration in stage 2. The initial speed was often taken to be zero.
This very simple part caused problems for many who were unable to calculate the distances travelled in each stage, or add these together correctly.