Agray kangaroo can bound across a flat stretch of ground with each jump carrying it 10 m from the takeoff point. you may want to review ( pages 83 - 85) . part a if the kangaroo leaves the ground at a 18 â angle, what is its takeoff speed ?

Takeoff speed of Kangaroo = 12.91 m/s

Explanation:

  The distance reached by Kangaroo =  10 meter

  Angle at which it jumps = 18°

  The motion of Kangaroo is like a projectile, the distance traveled is the range of projectile.

   Range of projectile = Time taken for the projectile to reach ground* Horizontal velocity

   Time taken for the projectile to reach ground:

       Time taken = Two times of the time taken for the projectile to reach maximum height

       Time taken for the projectile to reach maximum height = Vertical speed / Acceleration = u sin θ/g

      Time taken for the projectile to reach ground = 2 u sin θ/g

  So Range of projectile =

 We have Range = 10 meter, θ = 18⁰

    Substituting

 Takeoff speed of Kangaroo = 12.91 m/s

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