| Date | May 2012 | Marks available | 2 | Reference code | 12M.1.sl.TZ1.3 |
| Level | SL only | Paper | 1 | Time zone | TZ1 |
| Command term | Express | Question number | 3 | Adapted from | N/A |
Question
Ross is a star that is 82 414 080 000 000 km away from Earth. A spacecraft, launched from Earth, travels at 48 000 kmh–1 towards Ross.
Calculate the exact time, in hours, for the spacecraft to reach the star Ross.
Give your answer to part (a) in years. (Assume 1 year = 365 days)
Give your answer to part (b) in the form a×10k, where 1 ≤ a < 10 and \(k \in \mathbb{Z}\).
Markscheme
\(\frac{{{\text{82 414 080 000 000}}}}{{48\;000}}\) (M1)
Note: Award (M1) for correct substitution in correct formula.
1 716 960 000 (hours) (A1) (C2)
[2 marks]
\(\frac{{{\text{their (a)}}}}{{24 \times 365}}\) (M1)
196 000 (years) (A1)(ft) (C2)
Note: Award (A1)(ft) from their part (a).
[2 marks]
1.96×105 (A1)(ft)(A1)(ft) (C2)
Note: Award (A1)(ft) for 1.96 (accept 1.96000), (A1)(ft) for 105 . Follow through from their answer to part (b).
[2 marks]
Examiners report
(a) The large numbers given in the stem of this question led to some candidates being a factor of 10 out in their answer to part (a) and therefore losing at least the A mark. Errors were compounded in this first part of the question with some candidates dividing by 48000–1 which effectively meant multiplying by 48000. Much good work, however, was seen in the remaining two parts of the question with candidates well able to show a correct standard form from their figures.
(a) The large numbers given in the stem of this question led to some candidates being a factor of 10 out in their answer to part (a) and therefore losing at least the A mark. Errors were compounded in this first part of the question with some candidates dividing by 48000–1 which effectively meant multiplying by 48000. Much good work, however, was seen in the remaining two parts of the question with candidates well able to show a correct standard form from their figures.
(a) The large numbers given in the stem of this question led to some candidates being a factor of 10 out in their answer to part (a) and therefore losing at least the A mark. Errors were compounded in this first part of the question with some candidates dividing by 48000–1 which effectively meant multiplying by 48000. Much good work, however, was seen in the remaining two parts of the question with candidates well able to show a correct standard form from their figures.
