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Date May 2021 Marks available 4 Reference code 21M.2.AHL.TZ2.6
Level Additional Higher Level Paper Paper 2 Time zone Time zone 2
Command term Find Question number 6 Adapted from N/A

Question

A particle P moves along the x-axis. The velocity of P is v m s1 at time t seconds, where v=2t2+16t24 for t0.

Find the times when P is at instantaneous rest.

[2]
a.

Find the magnitude of the particle’s acceleration at 6 seconds.

[4]
b.

Find the greatest speed of P in the interval 0t6.

[2]
c.

The particle starts from the origin O. Find an expression for the displacement of P from O at time t seconds.

[4]
d.

Find the total distance travelled by P in the interval 0t4.

[3]
e.

Markscheme

solving v=0           M1

t=2, t=6               A1

 

[2 marks]

a.

use of power rule             (M1)

dvdt=-4t+16             (A1)

t=6

a=-8             (A1)

magnitude =8m s-2             A1

 

[4 marks]

b.

using a sketch graph of v            (M1)

24m s-1             A1

 

[2 marks]

c.

METHOD ONE

x=v dt

attempt at integration of v            (M1)

-2t33+8t2-24t +c             A1

attempt to find c (use of t=0, x=0)            (M1)

c=0                    A1

x=-2t33+8t2-24t

 

METHOD TWO

x=0tv dt

attempt at integration of v            (M1)

-2t33+8t2-24t0t             A1

attempt to substituted limits into their integral           (M1)

x=-2t33+8t2-24t             A1

 

[4 marks]

d.

04v dt            (M1)(A1)


Note: Award M1 for using the absolute value of v, or separating into two integrals, A1 for the correct expression.


=32m            A1

 

[3 marks]

e.

Examiners report

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

Syllabus sections

Topic 5—Calculus » AHL 5.13—Kinematic problems
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Topic 5—Calculus

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