8. Exercises

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</div>{{#NAVCONTENT:Answer|Answer 8.2|Solution a|Solution 8.2a|Solution b|Solution 8.2b}}
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===Exercise 8.3===
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The acceleration of a body is (<math>2\mathbf{i}+3\mathbf{j}</math>) <math>\text{m}{{\text{s}}^{-2}}</math>. If the body starts at rest at the origin and accelerates for 4 seconds find the velocity and position of the body at the end of the 4 seconds. The unit vectors <math>\mathbf{i}</math> and <math>\mathbf{j}</math> are perpendicular.
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[[Image:E6.1.GIF]]
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</div>{{#NAVCONTENT:Answer|Answer 8.3|Solution|Solution 8.3}}

Revision as of 16:01, 12 September 2009

       Theory          Exercises      


Exercise 8.1


The acceleration of a jet-ski is (\displaystyle 0.9\mathbf{i}+0.7\mathbf{j}) \displaystyle \text{m}{{\text{s}}^{-2}}. Its initial velocity is 4\displaystyle \mathbf{i} \displaystyle \text{m}{{\text{s}}^{-1}} and its initial position is (\displaystyle 400\mathbf{i}+350\mathbf{j}) m. The unit vectors are directed east and north respectively.

a) Find the velocity of the jet-ski when t = 10 seconds.

b) Find the position of the jet-ski when t = 10 seconds.



Exercise 8.2


A particle is set into motion on a smooth inclined plane. The initial velocity of the particle is 5\displaystyle \mathbf{i} \displaystyle \text{m}{{\text{s}}^{-1}}, its acceleration is -4\displaystyle \mathbf{j} \displaystyle \text{m}{{\text{s}}^{-2}} and its initial position is (\displaystyle 18\mathbf{i}+14\mathbf{j}) m, where \displaystyle \mathbf{i} and \displaystyle \mathbf{j} are perpendicular unit vectors that lie in the plane in which the particle is moving.

a) Find the velocity of the particle after it has been moving for 4 seconds.

b) Find the position of the particle after it has been moving for 8 seconds.


Exercise 8.3

The acceleration of a body is (\displaystyle 2\mathbf{i}+3\mathbf{j}) \displaystyle \text{m}{{\text{s}}^{-2}}. If the body starts at rest at the origin and accelerates for 4 seconds find the velocity and position of the body at the end of the 4 seconds. The unit vectors \displaystyle \mathbf{i} and \displaystyle \mathbf{j} are perpendicular.

Image:E6.1.GIF