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A cyclist is travelling at 15 ms-1, she applies brakes so that she doesn't collide with the wall in front of her at a distance of 18 m. Calculate the magnitude of deceleration.

Correct answer: A. 6.3 ms-2

  • A. 6.3 ms-2
  • B. 5.3 ms-1
  • C. 13 ms-1
  • D. 12.5 ms-1

Explanation

Initial velocity, u=15m/sFinal velocity, v=0m/sDistance, s=18mAcceleration, a=?Using relation, v2 −u2 =2as02 −(15)2 =2a×18−225=36aa= 36 −225 =−6.25m/s2So, deceleration is 6.25m/s2 which is equal 6.3m/s2

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Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.

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