Date | May 2019 | Marks available | 6 | Reference code | 19M.1.AHL.TZ1.H_5 |
Level | Additional Higher Level | Paper | Paper 1 (without calculator) | Time zone | Time zone 1 |
Command term | Find | Question number | H_5 | Adapted from | N/A |
Question
A camera at point C is 3 m from the edge of a straight section of road as shown in the following diagram. The camera detects a car travelling along the road at = 0. It then rotates, always pointing at the car, until the car passes O, the point on the edge of the road closest to the camera.
A car travels along the road at a speed of 24 ms−1. Let the position of the car be X and let OĈX = θ.
Find , the rate of rotation of the camera, in radians per second, at the instant the car passes the point O .
Markscheme
* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.
let OX =
METHOD 1
(or −24) (A1)
(M1)
A1
EITHER
A1
attempt to substitute for into their differential equation M1
OR
A1
attempt to substitute for into their differential equation M1
THEN
(rad s−1) A1
Note: Accept −8 rad s−1.
METHOD 2
(or −24) (A1)
A1
attempt to differentiate implicitly with respect to M1
A1
attempt to substitute for into their differential equation M1
(rad s−1) A1
Note: Accept −8 rad s−1.
Note: Can be done by consideration of CX, use of Pythagoras.
METHOD 3
let the position of the car be at time be from O (A1)
M1
Note: For award A0M1 and follow through.
EITHER
attempt to differentiate implicitly with respect to M1
A1
attempt to substitute for into their differential equation M1
OR
M1
A1
at O, A1
THEN
A1
[6 marks]