9. A body is dropped from a balloon which ismoving upward with a speed

1.	9. A body is dropped from a balloon which ismoving upward with a speed of10 m/s. The body is dropped when the balloonis at a height of 390 m from thesurface of the earth. Find the approximatetime taken by the body to reach thesurface of the earth. Take g = 10 m/s2.LA10
Answer» First, we write all the known quantitiesa= -10m's^2s= 390 mu= +10m/ss=ut + 1/2at^2s=10t + 5t^2-390=10t + 5t^2-78= 2t - t^2t^2 - 2t - 78 = 0d= b^2 - 4acd= 4 + 312d= 316-b±√d/2a2±2√79/2=1±79. therefore time taken to hit the ground will be 1+√79(In the answer 1 is being added, because it is the time taken to reverse the direction of velocity from upwards to downwards. Aa initially the object is moving upwards and then it starts to fall downwards.

9. A body is dropped from a balloon which ismoving upward with a speed of10 m/s. The body is dropped when the balloonis at a height of 390 m from thesurface of the earth. Find the approximatetime taken by the body to reach thesurface of the earth. Take g = 10 m/s2.LA10

Answer»

First, we write all the known quantitiesa= -10m's^2s= 390 mu= +10m/ss=ut + 1/2at^2s=10t + 5t^2-390=10t + 5t^2-78= 2t - t^2t^2 - 2t - 78 = 0d= b^2 - 4acd= 4 + 312d= 316-b±√d/2a2±2√79/2=1±79.

therefore time taken to hit the ground will be 1+√79(In the answer 1 is being added, because it is the time taken to reverse the direction of velocity from upwards to downwards. Aa initially the object is moving upwards and then it starts to fall downwards.

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9. A body is dropped from a balloon which ismoving upward with a speed of10 m/s. The body is dropped when the balloonis at a height of 390 m from thesurface of the earth. Find the approximatetime taken by the body to reach thesurface of the earth. Take g = 10 m/s2.LA10

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