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Date November 2015 Marks available 4 Reference code 15N.2.hl.TZ0.9
Level HL only Paper 2 Time zone TZ0
Command term Find Question number 9 Adapted from N/A

Question

A particle can move along a straight line from a point O. The velocity v, in ms1, is given by the function v(t)=1esint2 where time t0 is measured in seconds.

Write down the first two times t1, t2>0, when the particle changes direction.

[2]
a.

(i)     Find the time t<t2 when the particle has a maximum velocity.

(ii)     Find the time t<t2 when the particle has a minimum velocity.

[4]
b.

Find the distance travelled by the particle between times t=t1 and t=t2.

[2]
c.

Markscheme

t1=1.77 (s)(=π (s))andt2=2.51 (s)(=2π (s))     A1A1

[2 marks]

a.

(i)     attempting to find (graphically or analytically) the first tmax     (M1)

t = 1.25{\text{ (s)}}\;\;\;\left( { = \sqrt {\frac{\pi }{2}} {\text{ (s)}}} \right)     A1

(ii)     attempting to find (graphically or analytically) the first {t_{\min }}     (M1)

t = 2.17{\text{ (s)}}\;\;\;\left( { = \sqrt {\frac{{3\pi }}{2}} {\text{ (s)}}} \right)     A1

[4 marks]

b.

distance travelled = \left| {\int_{1.772 \ldots }^{2.506 \ldots } {1 - {{\text{e}}^{ - \sin {t^2}}}{\text{d}}t} } \right|\;\;\;(or equivalent)     (M1)

= 0.711{\text{ (m)}}     A1

 

Note:     Award M1 for attempting to form a definite integral involving 1 - {{\text{e}}^{ - \sin {t^2}}}. To award the A1, correct limits leading to 0.711 must include the use of absolute value or a statement such as “distance must be positive”.

In part (c), award A1FT for a candidate working in degree mode \left( {5.39{\text{ (m)}}} \right).

[2 marks]

Total [8 marks]

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Topic 6 - Core: Calculus » 6.6 » Kinematic problems involving displacement s, velocity v and acceleration a.
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