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Dynamics Question #4

  • Thread starter looi76
  • Start date
  • #1
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Homework Statement


An aeroplane of mass 20 tonne lands on an aircraft carrier with a horizontal velocity of [tex]80ms^{-1}[/tex]. A [tex]100m[/tex] runway is available.
(a) What must be the acceleration to bring the aeroplane to rest safely?
(b) What retarding force is requires?

Homework Equations


[tex]v^2 = u^2 + 2as[/tex]
[tex]F = m.a[/tex]

The Attempt at a Solution


[tex]m = 90 \times 10^3kg \ , \ v = 80ms^{-1} \ , \s = 100m[/tex]

(a) [tex]v^2 = u^2 + 2as[/tex]
[tex]0^2 = 80^2 + 2 \times a \times 100[/tex]
[tex]-80^2 = 200a[/tex]
[tex]a = \frac{-80^2}{200}[/tex]
[tex]a = -32ms^{-2}[/tex]

(b) [tex]F = m.a[/tex]
[tex]F = 90 \times 10^3 \times -32[/tex]
[tex]F = -2.9 \times 10^6 N[/tex]

Are my answers correct?
 
Last edited:

Answers and Replies

  • #2
alphysicist
Homework Helper
2,238
1
Hi looi76,

I think your mass for the airplane is incorrect. Am I misunderstanding your numbers? How did you get 90000 kg?
 
  • #3
783
9
Check your conversion factors for tonne to kilograms.
 

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